Comparison of treatment effect estimates from prospective nonrandomized studies with propensity score analysis and randomized controlled trials of surgical procedures. Ann Surg. 2014;259:18-25. [PMID: 24096758 DOI: 10.1097/sla.0000000000000256]

Treatment Effects in Randomized and Nonrandomized Studies of Pharmacological Interventions: A Meta-Analysis

Importance

Randomized clinical trials (RCTs) are widely regarded as the methodological benchmark for assessing clinical efficacy and safety of health interventions. There is growing interest in using nonrandomized studies to assess efficacy and safety of new drugs.

Objective

To determine how treatment effects for the same drug compare when evaluated in nonrandomized vs randomized studies.

Data Sources

Meta-analyses published between 2009 and 2018 were identified in MEDLINE via PubMed and the Cochrane Database of Systematic Reviews. Data analysis was conducted from October 2019 to July 2024.

Study Selection

Meta-analyses of pharmacological interventions were eligible for inclusion if both randomized and nonrandomized studies contributed to a single meta-analytic estimate.

Data Extraction and Synthesis

For this meta-analysis using a meta-epidemiological framework, separate summary effect size estimates were calculated for nonrandomized and randomized studies within each meta-analysis using a random-effects model and then these estimates were compared. The reporting of this study followed the Guidelines for Reporting Meta-Epidemiological Methodology Research and relevant portions of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guideline.

Main Outcome and Measures

The primary outcome was discrepancies in treatment effects obtained from nonrandomized and randomized studies, as measured by the proportion of meta-analyses where the 2 study types disagreed about the direction or magnitude of effect, disagreed beyond chance about the effect size estimate, and the summary ratio of odds ratios (ROR) obtained from nonrandomized vs randomized studies combined across all meta-analyses.

Results

A total of 346 meta-analyses with 2746 studies were included. Statistical conclusions about drug benefits and harms were different for 130 of 346 meta-analyses (37.6%) when focusing solely on either nonrandomized or randomized studies. Disagreements were beyond chance for 54 meta-analyses (15.6%). Across all meta-analyses, there was no strong evidence of consistent differences in treatment effects obtained from nonrandomized vs randomized studies (summary ROR, 0.95; 95% credible interval [CrI], 0.89-1.02). Compared with experimental nonrandomized studies, randomized studies produced on average a 19% smaller treatment effect (ROR, 0.81; 95% CrI, 0.68-0.97). There was increased heterogeneity in effect size estimates obtained from nonrandomized compared with randomized studies.

Conclusions and Relevance

In this meta-analysis of treatment effects of pharmacological interventions obtained from randomized and nonrandomized studies, there was no overall difference in effect size estimates between study types on average, but nonrandomized studies both overestimated and underestimated treatment effects observed in randomized studies and introduced additional uncertainty. These findings suggest that relying on nonrandomized studies as substitutes for RCTs may introduce additional uncertainty about the therapeutic effects of new drugs.

Long term outcomes after lobar versus sublobar resection for patients with Non-Small cell lung Cancer: Systematic review and individual patient data Meta-Analysis

OBJECTIVES

Surgical resection remains the primary treatment for early-stage non-small cell lung cancer (NSCLC), with lobectomy considered the standard approach. However, recent evidence suggests that sublobar resection may be an alternative option for select patients.

MATERIALS AND METHODS

A systematic review and meta-analysis were conducted following PRISMA guidelines. Randomized controlled trials (RCTs) and propensity-score matched (PSM) cohort studies comparing lobectomy and sublobar resection in NSCLC patients were included. The primary outcome was overall survival (OS), and secondary outcomes included disease-free survival (DFS), 30-day mortality, and cancer recurrence rates. Individual patient data (IPD) were reconstructed from Kaplan-Meier curves, and one-stage and two-stage meta-analyses were performed.

RESULTS

A total of 18 studies involving 6,075 NSCLC patients (3,119 undergoing lobectomy, 2,956 undergoing sublobar resection) were included. Lobectomy was associated with significantly better OS compared to sublobar resection (hazard ratio [HR]: 0.78, 95 % confidence interval [CI]: 0.68-0.89, p < 0.001). However, when sublobar resection was further divided into segmentectomy and wedge resection, no significant difference in OS was observed between lobectomy and segmentectomy (HR:0.92, 95 %CI: 0.75-1.14, p = 0.464) whereas lobar resection was associated with better OS compared to wedge resection (HR:0.52, 95 %CI: 0.41-0.67, p < 0.001). DFS outcomes were similar between lobectomy and sublobar resection (HR:0.98, 95 %CI: 0.84-1.14, p = 0.778).

CONCLUSION

Lobectomy is associated with better overall survival compared to sublobar resection in NSCLC patients. However, when sublobar resection is subdivided, segmentectomy shows comparable outcomes to lobectomy, while wedge resection is inferior. These findings support the consideration of segmentectomy as the surgical option of choice for Stage IA NSCLC patients.

Robotic versus laparoscopic right colectomy for nonmetastatic pT4 colon cancer: A European multicentre propensity score-matched analysis

AIM

Minimally invasive surgery has been increasingly adopted for locally advanced colon cancer. However, evidence comparing robotic (RRC) versus laparoscopic right colectomy (LRC) for nonmetastatic pT4 cancers is lacking.

METHODS

This was a multicentre propensity score-matched (PSM) study of a cohort of consecutive patients with pT4 right colon cancer treated with RRC or LRC. The two surgical approaches were compared in terms of R0, number of lymph nodes harvested, intra- and postoperative complication rates, overall (OS), and disease-free survival (DFS).

RESULTS

Among a total of 200 patients, 39 RRC were compared with 78 PS-matched LRC patients. The R0 rate was similar between RRC and LRC (92.3% vs. 96.2%, respectively; p = 0.399), as was the odds of retrieving 12 or more lymph nodes (97.4% vs. 96.2%; p = 1). No significant difference was noted for the mean operating time (192.9 min vs. 198.3 min; p = 0.750). However, RRC was associated with fewer conversions to laparotomy (5.1% vs. 20.5%; p = 0.032), less blood loss (36.9 vs. 95.2 mL; p < 0.0001), fewer postoperative complications (17.9% vs. 41%; p = 0.013), a shorter time to flatus (2 vs. 2.8 days; p = 0.009), and a shorter hospital stay (6.4 vs. 9.5 days; p < 0.0001) compared with LRC. These results were confirmed even when converted procedures were excluded from the analysis. The 1-, 3- and 5-year OS (p = 0.757) and DFS (p = 0.321) did not significantly differ between RRC and LRC.

CONCLUSION

Adequate oncological outcomes are observed for RRC and LRC performed for pT4 right colon cancer. However, RRC is associated with lower conversion rates and improved short-term postoperative outcomes.

Systematic reviews and meta-analyses in neurosurgery Part II: a guide to designing the protocol

Despite clearly established guidelines, recent audits have found the conduct and reporting of systematic reviews and meta-analyses (SRMAs) within neurosurgery to be relatively lackluster in methodological rigor and compliance. Protocols of SRMAs allow for planning and documentation of review methods, guard against arbitrary decision-making during the review process, and enable readers to assess for the presence of selective reporting. To aid transparency, authors should provide sufficient detail in their protocol so that the readers could reproduce the study themselves. Development of our guideline drew heavily from the Preferred Reporting Items for Systematic Reviews and Meta-analyses Protocols (PRISMA-P) initiative. The objective of this article is not to enumerate every detail of this checklist, but to provide guidance to authors preparing their protocol, with examples, for a systematic review in neurosurgery. Particularly, we emphasize on the PICO framework - population (P), interventions (I), comparators (C), outcomes (O) - which is central to constructing a clinical question, defining the scope of the systematic review, defining and prioritizing the primary outcome, to specifying the eligibility criteria, designing the search strategy, and identifying potential sources of heterogeneity. We encourage our readers to make use of this guideline alongside the PRISMA-P 2015 statement, when drafting and appraising systematic review protocols.

Systematic reviews and meta-analyses in neurosurgery part I: interpreting and critically appraising as a guide for clinical practice

Neurosurgeons are inundated with the Herculean task to keep abreast with the rapid pace at which clinical research is proliferating. Systematic reviews and meta-analyses (SRMAs) have consequently surged in popularity because when executed properly, they constitute the highest level of evidence, and may save busy neurosurgeons many hours of combing the literature. Well-executed SRMAs may prove instructive for clinical practice, but poorly conducted reviews sow confusion and may potentially cause harm. Unfortunately, many SRMAs within neurosurgery are relatively lackluster in methodological rigor. When neurosurgeons apply the results of an SRMA to patient care, they should start by evaluating the extent to which the employed methods have likely protected against misleading results. The present article aims to educate the reader about how to interpret an SRMA, to assess the potential relevance of its results in the special context of the neurosurgical patient population.

Robotic Versus Laparoscopic Liver Resection in Various Settings: An International Multicenter Propensity Score Matched Study of 10.075 Patients

OBJECTIVE

To compare the perioperative outcomes of robotic liver surgery (RLS) and laparoscopic liver surgery (LLS) in various settings.

BACKGROUND

Clear advantages of RLS over LLS have rarely been demonstrated, and the associated costs of robotic surgery are generally higher than those of laparoscopic surgery. Therefore, the exact role of the robotic approach in minimally invasive liver surgery remains to be defined.

METHODS

In this international retrospective cohort study, the outcomes of patients who underwent RLS and LLS for all indications between 2009 and 2021 in 34 hepatobiliary referral centers were compared. Subgroup analyses were performed to compare both approaches across several types of procedures: (1) minor resections in the anterolateral (2, 3, 4b, 5, and 6) or (2) posterosuperior segments (1, 4a, 7, 8), and (3) major resections (≥3 contiguous segments). Propensity score matching was used to mitigate the influence of selection bias. The primary outcome was textbook outcome in liver surgery (TOLS), previously defined as the absence of intraoperative incidents ≥grade 2, postoperative bile leak ≥grade B, severe morbidity, readmission, and 90-day or in-hospital mortality with the presence of an R0 resection margin in case of malignancy. The absence of a prolonged length of stay was added to define TOLS+.

RESULTS

Among the 10.075 included patients, 1.507 underwent RLS and 8.568 LLS. After propensity score matching, both groups constituted 1.505 patients. RLS was associated with higher rates of TOLS (78.3% vs 71.8%, P < 0.001) and TOLS+ (55% vs 50.4%, P = 0.026), less Pringle usage (39.1% vs 47.1%, P < 0.001), blood loss (100 vs 200 milliliters, P < 0.001), transfusions (4.9% vs 7.9%, P = 0.003), conversions (2.7% vs 8.8%, P < 0.001), overall morbidity (19.3% vs 25.7%, P < 0.001), and microscopically irradical resection margins (10.1% vs. 13.8%, P = 0.015), and shorter operative times (190 vs 210 minutes, P = 0.015). In the subgroups, RLS tended to have higher TOLS rates, compared with LLS, for minor resections in the posterosuperior segments (n = 431 per group, 75.9% vs 71.2%, P = 0.184) and major resections (n = 321 per group, 72.9% vs 67.5%, P = 0.086), although these differences did not reach statistical significance.

CONCLUSIONS

While both produce excellent outcomes, RLS might facilitate slightly higher TOLS rates than LLS.

Impact of neoadjuvant chemotherapy on short-term outcomes after simple and complex minimally invasive minor hepatectomy for colorectal liver metastases: A propensity-score matched and coarsened exact matched study

BACKGROUND

In the last three decades, minimally invasive liver resection has been replacing conventional open approach in liver surgery. More recently, developments in neoadjuvant chemotherapy have led to increased multidisciplinary management of colorectal liver metastases with both medical and surgical treatment modalities. However, the impact of neoadjuvant chemotherapy on the surgical outcomes of minimally invasive liver resections remains poorly understood.

METHODS

A multicenter, international, database of 4998 minimally invasive minor hepatectomy for colorectal liver metastases was used to compare surgical outcomes in patients who received neoadjuvant chemotherapy with surgery alone. To correct for baseline imbalance, propensity score matching, coarsened exact matching and inverse probability treatment weighting were performed.

RESULTS

2546 patients met the inclusion criteria. After propensity score matching there were 759 patients in both groups and 383 patients in both groups after coarsened exact matching. Baseline characteristics were equal after both matching strategies. Neoadjuvant chemotherapy was not associated with statistically significant worse surgical outcomes of minimally invasive minor hepatectomy.

CONCLUSION

Neoadjuvant chemotherapy had no statistically significant impact on short-term surgical outcomes after simple and complex minimally invasive minor hepatectomy for colorectal liver metastases.

Laparoscopic liver resection is superior to radiofrequency ablation for small hepatocellular carcinoma: a systematic review and meta-analysis of propensity score-matched studies

BACKGROUND

The approach in small hepatocellular carcinoma (HCC) is controversial, no prospective randomized trials to compare ablative or surgical approaches. We compared the surgical and oncological outcomes after laparoscopic hepatectomy (LH) and radiofrequency ablation (RFA) in small HCC patients based on matched cohort studies that performed propensity score matching (PSM).

METHODS

We systemically searched the PubMed, Cochrane Library, Embase, Web of Science, and the Chinese BioMedical Literature (CBM) databases. All published propensity score-matched studies that compared LH and RFA for small HCC were included in this study.

RESULTS

Eight studies with a total of 1273 small HCC cases were included. The results of the meta-analysis revealed that there was no significant difference in the 1- year overall survival (OS) rate between the two groups, whereas the LH group had significantly higher 3- year overall survival rate (RR = 1.14, 95% CI 1.08-1.20, p < 0.00001) as well as 1- and 3-year disease-free survival (DFS) rates (RR = 1.31, 95% CI 1.22-1.42, p < 0.00001; RR = 1.66, 95% CI 1.46-1.90, p < 0.00001) than the RFA group. Meanwhile, the local recurrence rate and intrahepatic distant recurrence rate were significantly lower in the LH group than in the RFA group (RR = 0.29, 95% CI 0.20-0.42, p < 0.00001; RR = 0.67, 95% CI 0.49-0.92, p = 0.01). In comparison with the LH group, the RFA group had a lower incidence of overall and major postoperative complications (RR = 1.81, 95% CI 1.47-2.24, p < 0.00001; RR = 2.76, 95% CI 1.48-5.12, p = 0.001), but there was no significant difference in postoperative mortality between the two groups. In addition, further comparison of single postoperative complications showed that the incidence of ascites was lower in the RFA group than in the LH group (RR = 3.62, 95% CI 1.64-7.96, p = 0.001), whereas there was no significant difference in the incidence of postoperative bleeding, abdominal infection and bile leakage between the two groups (RR = 3.50, 95% CI 0.74-16.61, p = 0.11; RR = 5.00, 95% CI 0.59-42.23, p = 0.14; RR = 4.00, 95% CI 0.45-35.23, p = 0.21). Besides, the hospital stay was shorter in the RFA group than in the LH group (MD = 4.29, 95% CI 2.06-6.53, p = 0.0002).

CONCLUSIONS

Our meta-analysis demonstrated that in comparison with RFA in the treatment of small HCC, LH provided superior long-term OS and DFS together with lower rates of local and intrahepatic distant recurrence after surgery. However, RFA was associated with better short-term outcomes.

Laparoscopic versus open gastrectomy for nonmetastatic T4a gastric cancer: a meta-analysis of reconstructed individual participant data from propensity score-matched studies

BACKGROUND

​The applicability of laparoscopy to nonmetastatic T4a patients with gastric cancer remains unclear due to the lack of high-quality evidence. The purpose of this study was to compare the survival rates of laparoscopic gastrectomy (LG) versus open gastrectomy (OG) for these patients through a meta-analysis of reconstructed individual participant data from propensity score-matched studies.

METHODS

PubMed, Embase, Web of Science, Cochrane library and CNKI were examined for relevant studies without language restrictions through July 25, 2023. Individual participant data on overall survival (OS) and disease-free survival (DFS) were extracted from the published Kaplan-Meier survival curves. One-stage and two-stage meta-analyses were performed. In addition, data regarding surgical outcomes and recurrence patterns were also collected, which were meta-analyzed using traditional aggregated data.

RESULTS

Six studies comprising 1860 patients were included for analysis. In the one-stage meta-analyses, the results demonstrated that LG was associated with a significantly better DFS (Random-effects model: P = 0.027; Restricted mean survival time [RMST] up to 5 years: P = 0.033) and a comparable OS (Random-effects model: P = 0.135; RMST up to 5 years: P = 0.053) than OG for T4a gastric cancer patients. Two-stage meta-analyses resulted in similar results, with a 13% reduced hazard of cancer-related death (P = 0.04) and 10% reduced hazard of overall mortality (P = 0.11) in the LG group. For secondary outcomes, the pooled results showed an association of LG with less estimated blood loss, faster postoperative recovery and more retrieved lymph nodes.

CONCLUSION

Laparoscopic surgery for patients with nonmetastatic T4a disease is associated with a potential survival benefit and improved surgical outcomes.

Evaluating agreement between evidence from randomised controlled trials and cohort studies in nutrition: a meta-research replication study

This meta-research study aims to evaluate the agreement of effect estimates between bodies of evidence (BoE) from RCTs and cohort studies included in the same nutrition evidence synthesis, to identify factors associated with disagreement, and to replicate the findings of a previous study. We searched Medline, Epistemonikos and the Cochrane Database of Systematic Reviews for nutrition systematic reviews that included both RCTs and cohort studies for the same patient-relevant outcome or intermediate-disease marker. We rated similarity of PI/ECO (population, intervention/exposure, comparison, outcome) between BoE from RCTs and cohort studies. Agreement of effect estimates across BoE was analysed by pooling ratio of risk ratios (RRR) for binary outcomes and difference of standardised mean differences (DSMD) for continuous outcomes. We performed subgroup and sensitivity analyses to explore determinants associated with disagreements. We included 82 BoE-pairs from 51 systematic reviews. For binary outcomes, the RRR was 1.04 (95% confidence interval (CI) 0.99 to 1.10, I2 = 59%, τ2 = 0.02, prediction interval (PI) 0.77 to 1.41). For continuous outcomes, the pooled DSMD was  - 0.09 (95% CI  - 0.26 to 0.09, PI  - 0.55 to 0.38). Subgroup analyses yielded that differences in type of intake/exposure were drivers towards disagreement. We replicated the findings of a previous study, where on average RCTs and cohort studies had similar effect estimates. Disagreement and wide prediction intervals were mainly driven by PI/ECO-dissimilarities. More research is needed to explore other potentially influencing factors (e.g. risk of bias) on the disagreement between effect estimates of both BoE.Trial registration: CRD42021278908.

Off-clamp vs on-clamp robot-assisted partial nephrectomy: a systematic review and meta-analysis

OBJECTIVE

To compare intra- and postoperative outcomes between off-clamp and on-clamp robot-assisted partial nephrectomy (RAPN), using data from randomised controlled trials (RCTs) or covariate-matched studies (propensity score-matched or matched-pair analysis).

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant literature review was conducted on PubMed, EMBASE, Scopus and CENTRAL for relevant studies comparing off-clamp to on-clamp RAPN. Primary outcomes were estimated blood loss, postoperative percentage decrease in estimated glomerular filtration rate (eGFR), and margin positive rate. Secondary outcomes were operative time, postoperative eGFR, length of stay, all postoperative complications, major complications, and need for transfusion. Random-effects meta-analyses were performed to generate mean differences (MDs) or odds ratios (ORs).

RESULTS

A total of 10 studies (2307 patients) were shortlisted for analysis. There was no significant difference in estimated operative blood loss between off-clamp and on-clamp RAPN (MD 21.9 mL, 95% confidence interval [CI] -0.9 to 44.7 mL; P = 0.06, I2  = 58%). Off-clamp RAPN yielded a smaller postoperative eGFR deterioration (MD 3.10%, 95% CI 1.05-5.16%; P = 0.008, I2  = 13%) and lower odds of margin positivity (OR 0.62, 95% CI 0.40-0.94; P = 0.03, I2  = 0%). No significant differences were found for all secondary outcomes.

CONCLUSIONS

Off-clamp and on-clamp RAPN are similarly effective approaches for selected renal masses. Within the classic trifecta of PN outcomes, off-clamp RAPN yields similar rates of perioperative complications and may possibly offer better preservation of renal function and reduced margin-positive rates.

Laparoscopic Treatment of Perforated Peptic Ulcer: A Propensity Score-Matched Comparison of Interrupted Stitches Repair versus Knotless Barbed Suture

Background: Peptic ulcers result from imbalanced acid production, and in recent decades, proton pump inhibitors have proven effective in treating them. However, perforated peptic ulcers (PPU) continue to occur with a persistent high mortality rate when not managed properly. The advantages of the laparoscopic approach have been widely acknowledged. Nevertheless, concerning certain technical aspects of this method, such as the best gastrorrhaphy technique, the consensus remains elusive. Consequently, the choice tends to rely on individual surgical experiences. Our study aimed to compare interrupted stitches versus running barbed suture for laparoscopic PPU repair. Methods: We conducted a retrospective study utilizing propensity score matching analysis on patients who underwent laparoscopic PPU repair. Patients were categorised into two groups: Interrupted Stitches Suture (IStiS) and Knotless Suture (KnotS). We then compared the clinical and pathological characteristics of patients in both groups. Results: A total of 265 patients underwent laparoscopic PPU repair: 198 patients with interrupted stitches technique and 67 with barbed knotless suture. Following propensity score matching, each group (IStiS and KnotS) comprised 56 patients. The analysis revealed that operative time did not differ between groups: 87.9 ± 39.7 vs. 92.8 ± 42.6 min (p = 0.537). Postoperative morbidity (24.0% vs. 32.7%, p = 0.331) and Clavien-Dindo III (10.7% vs. 5.4%, p = 0.489) were more frequently observed in the KnotS group, without any significant difference. In contrast, we found a slightly higher mortality rate in the IStiS group (10.7% vs. 7.1%, p = 0.742). Concerning leaks, no differences emerged between groups (3.6% vs. 5.4%, p = 1.000). Conclusions: Laparoscopic PPU repair with knotless barbed sutures is a non-inferior alternative to interrupted stitches repair. Nevertheless, further research such as randomised trials, with a standardised treatment protocol according to ulcer size, are required to identify the best gastrorraphy technique.

Prognostic value of baseline neutrophil/lymphocyte ratio in HER2-positive metastatic breast cancer: exploratory analysis of data from the CLEOPATRA trial

PURPOSE

This study aimed to evaluate the prognostic role of the baseline neutrophil/lymphocyte ratio (NLR) in HER2-positive metastatic breast cancer (MBC) patients treated with trastuzumab/pertuzumab.

EXPERIMENTAL DESIGN

Data from 780 patients from the CLEOPATRA trial and 248 local patients were collected. Patients were divided into the low and high NLR subgroups by the NLR cutoff value. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) methods were used to control bias. Associations between the NLR and progression-free survival (PFS) and overall survival (OS) were analyzed.

RESULTS

The baseline characteristics of the subgroups were well balanced after PSM and IPTW. A low baseline NLR was associated with better PFS and OS in the trastuzumab and docetaxel (TH) group in the unadjusted, PSM and IPTW models. After IPTW, a low NLR, versus a high NLR, was associated with improved PFS (HR 1.35, 95% CI 1.07-1.70, P = 0.012) and OS (HR 1.47, 95% CI 1.12-1.94, P = 0.006) in the TH group. In patients undergoing treatment with trastuzumab and pertuzumab and docetaxel (THP), a low baseline NLR was also correlated with better PFS but not OS across the three models. After IPTW, a low NLR was associated with better PFS (HR 1.52, 95% CI 1.20-1.93, P = 0.001) than a high NLR in the THP group. Multivariate analyses showed that a low baseline NLR was a predictor for PFS and OS in the TH group and for PFS in the THP group in all three models. In the real-world setting, a low baseline NLR was a predictor of better PFS among patients treated with docetaxel plus trastuzumab without or with pertuzumab in the multivariate model (P = 0.015 and 0.008, respectively).

CONCLUSIONS

A low baseline NLR is associated with better survival outcomes among HER2-positive MBC patients receiving docetaxel plus trastuzumab/pertuzumab as first-line therapy.

Healthcare outcomes assessed with observational study designs compared with those assessed in randomized trials: a meta-epidemiological study

BACKGROUND

Researchers and decision-makers often use evidence from randomised controlled trials (RCTs) to determine the efficacy or effectiveness of a treatment or intervention. Studies with observational designs are often used to measure the effectiveness of an intervention in 'real world' scenarios. Numerous study designs and their modifications (including both randomised and observational designs) are used for comparative effectiveness research in an attempt to give an unbiased estimate of whether one treatment is more effective or safer than another for a particular population. An up-to-date systematic analysis is needed to identify differences in effect estimates from RCTs and observational studies. This updated review summarises the results of methodological reviews that compared the effect estimates of observational studies with RCTs from evidence syntheses that addressed the same health research question.

OBJECTIVES

To assess and compare synthesised effect estimates by study type, contrasting RCTs with observational studies. To explore factors that might explain differences in synthesised effect estimates from RCTs versus observational studies (e.g. heterogeneity, type of observational study design, type of intervention, and use of propensity score adjustment). To identify gaps in the existing research comparing effect estimates across different study types.

SEARCH METHODS

We searched MEDLINE, the Cochrane Database of Systematic Reviews, Web of Science databases, and Epistemonikos to May 2022. We checked references, conducted citation searches, and contacted review authors to identify additional reviews.

SELECTION CRITERIA

We included systematic methodological reviews that compared quantitative effect estimates measuring the efficacy or effectiveness of interventions tested in RCTs versus in observational studies. The included reviews compared RCTs to observational studies (including retrospective and prospective cohort, case-control and cross-sectional designs). Reviews were not eligible if they compared RCTs with studies that had used some form of concurrent allocation.

DATA COLLECTION AND ANALYSIS

Using results from observational studies as the reference group, we examined the relative summary effect estimates (risk ratios (RRs), odds ratios (ORs), hazard ratios (HRs), mean differences (MDs), and standardised mean differences (SMDs)) to evaluate whether there was a relatively larger or smaller effect in the ratio of odds ratios (ROR) or ratio of risk ratios (RRR), ratio of hazard ratios (RHR), and difference in (standardised) mean differences (D(S)MD). If an included review did not provide an estimate comparing results from RCTs with observational studies, we generated one by pooling the estimates for observational studies and RCTs, respectively. Across all reviews, we synthesised these ratios to produce a pooled ratio of ratios comparing effect estimates from RCTs with those from observational studies. In overviews of reviews, we estimated the ROR or RRR for each overview using observational studies as the reference category. We appraised the risk of bias in the included reviews (using nine criteria in total). To receive an overall low risk of bias rating, an included review needed: explicit criteria for study selection, a complete sample of studies, and to have controlled for study methodological differences and study heterogeneity. We assessed reviews/overviews not meeting these four criteria as having an overall high risk of bias. We assessed the certainty of the evidence, consisting of multiple evidence syntheses, with the GRADE approach.

MAIN RESULTS

We included 39 systematic reviews and eight overviews of reviews, for a total of 47. Thirty-four of these contributed data to our primary analysis. Based on the available data, we found that the reviews/overviews included 2869 RCTs involving 3,882,115 participants, and 3924 observational studies with 19,499,970 participants. We rated 11 reviews/overviews as having an overall low risk of bias, and 36 as having an unclear or high risk of bias. Our main concerns with the included reviews/overviews were that some did not assess the quality of their included studies, and some failed to account appropriately for differences between study designs - for example, they conducted aggregate analyses of all observational studies rather than separate analyses of cohort and case-control studies. When pooling RORs and RRRs, the ratio of ratios indicated no difference or a very small difference between the effect estimates from RCTs versus from observational studies (ratio of ratios 1.08, 95% confidence interval (CI) 1.01 to 1.15). We rated the certainty of the evidence as low. Twenty-three of 34 reviews reported effect estimates of RCTs and observational studies that were on average in agreement. In a number of subgroup analyses, small differences in the effect estimates were detected: - pharmaceutical interventions only (ratio of ratios 1.12, 95% CI 1.04 to 1.21); - RCTs and observational studies with substantial or high heterogeneity; that is, I2 ≥ 50% (ratio of ratios 1.11, 95% CI 1.04 to 1.18); - no use (ratio of ratios 1.07, 95% CI 1.03 to 1.11) or unclear use (ratio of ratios 1.13, 95% CI 1.03 to 1.25) of propensity score adjustment in observational studies; and - observational studies without further specification of the study design (ratio of ratios 1.06, 95% CI 0.96 to 1.18). We detected no clear difference in other subgroup analyses.

AUTHORS' CONCLUSIONS

We found no difference or a very small difference between effect estimates from RCTs and observational studies. These findings are largely consistent with findings from recently published research. Factors other than study design need to be considered when exploring reasons for a lack of agreement between results of RCTs and observational studies, such as differences in the population, intervention, comparator, and outcomes investigated in the respective studies. Our results underscore that it is important for review authors to consider not only study design, but the level of heterogeneity in meta-analyses of RCTs or observational studies. A better understanding is needed of how these factors might yield estimates reflective of true effectiveness.

Assessment of the DNA Mismatch Repair System Is Crucial in Colorectal Cancers Necessitating Adjuvant Treatment: A Propensity Score-Matched and Win Ratio Analysis

A deficient DNA mismatch repair (MMR) system is identified in a non-negligible part of sporadic colorectal cancers (CRCs), and its prognostic value remains controversial. High tumor mutational burden, along with a poor response to conventional chemotherapy and excellent results from immunotherapy, are the main features of this subset. The aim of this study was to evaluate the predictive value of DNA MMR system status for its best treatment. Four hundred and three CRC patients, operated on from 2014 to 2021 and not treated with immunotherapy, entered this study. Immunohistochemistry and polymerase chain reaction, as appropriate, were used to unequivocally group specimens into microsatellite stable (MSS) and instable (MSI) tumors. The win-ratio approach was utilized to compare composite outcomes. MSI tumors accounted for 12.9% of all series. The right tumor location represented the most important factor related to MSI. The status of the DNA MMR system did not appear to correlate with outcome in early-stage CRCs not requiring adjuvant treatment; in advanced stages undergoing conventional chemotherapy, MSI tumors showed significantly poorer overall and disease-free survival rates and the highest win ratio instead. The determination of DNA MMR status is crucial to recommending correct management. There is clear evidence that instable CRCs needing adjuvant therapy should undergo appropriate treatments.

Association between adjuvant chemotherapy and survival in stage I gastric cancer patients after curative resection

Background

The efficacy of adjuvant chemotherapy (AC) on survival outcomes of patients with stage I gastric cancer (GC) after curative resection remains controversial. We aimed to determine whether these patients would benefit from AC.

Methods

This retrospective study included patients with pathologically confirmed stage I GC who underwent curative resection between November 2010 and December 2020. Patients were divided into AC and non-AC groups, then a 1:1 propensity score matching (PSM) analysis was performed to minimize the selection bias. Potential risk factors including age, pN stage, pT stage, lymphovascular invasion, perineural invasion, tumor size, histological type, and carcinoembryonic antigen level were used as matching covariates. The recurrence-free survival (RFS) and disease-specific survival (DSS) were compared between groups using the Kaplan-Meier method.

Results

A total of 902 consecutive patients were enrolled and 174 (19.3%) patients were treated with AC. PSM created 123 pairs of patients. Before PSM, patients receiving AC had lower 10-year RFS rates (90% vs 94.6%, P = 0.035) than those who did not receive AC; the two groups had similar 10-year DSS rates (93.8% vs 95.0%, P = 0.240). After PSM, there were no statistical differences in the 10-year RFS (90.9% vs 93.0%, P = 0.507) or DSS rates (93.5% vs 93.6%, P = 0.811) between the two groups. Similar results were found in the stage IA and IB subgroups. Moreover, these findings were not affected by AC cycles.

Conclusions

The addition of AC could not provide survival benefits for patients with stage I GC after surgery and follow-up is thus recommended. However, large-scale randomized clinical trials are required.

Does changes in unicompartmental knee arthroplasty practice pattern influence reasons for revision?

Aims

The aim of this study was to describe the pattern of revision indications for unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) and any change to this pattern for UKA patients over the last 20 years, and to investigate potential associations to changes in surgical practice over time.

Methods

All primary knee arthroplasty surgeries performed due to primary osteoarthritis and their revisions reported to the Danish Knee Arthroplasty Register from 1997 to 2017 were included. Complex surgeries were excluded. The data was linked to the National Patient Register and the Civil Registration System for comorbidity, mortality, and emigration status. TKAs were propensity score matched 4:1 to UKAs. Revision risks were compared using competing risk Cox proportional hazard regression with a shared γ frailty component.

Results

Aseptic loosening (loosening) was the most common revision indication for both UKA (26.7%) and TKA (29.5%). Pain and disease progression accounted for 54.6% of the remaining UKA revisions. Infections and instability accounted for 56.1% of the remaining TKA revision. The incidence of revision due to loosening or pain decreased over the last decade, being the second and third least common indications in 2017. There was a decrease associated with fixation method for pain (hazard ratio (HR) 0.40; 95% confidence interval (CI) 0.17 to 0.94) and loosening (HR 0.29; 95% CI 0.10 to 0.81) for cementless compared to cemented, and units UKA usage for pain (HR 0.67, 95% CI 0.50 to 0.91), and loosening (HR 0.51; 95% CI 0.37 to 0.70) for high usage.

Conclusion

The overall revision patterns for UKA and TKA for the last 20 years are comparable to previous published patterns. We found large changes to UKA revision patterns in the last decade, and with the current surgical practice, revision due to pain or loosening are significantly less likely.

Assessing the use of observational methods and real-world data to emulate ongoing randomized controlled trials

BACKGROUND/AIMS

There has been growing interest in better understanding the potential of observational research methods in medical product evaluation and regulatory decision-making. Previously, we used linked claims and electronic health record data to emulate two ongoing randomized controlled trials, characterizing the populations and results of each randomized controlled trial prior to publication of its results. Here, our objective was to compare the populations and results from the emulated trials with those of the now-published randomized controlled trials.

METHODS

This study compared participants' demographic and clinical characteristics and study results between the emulated trials, which used structured data from OptumLabs Data Warehouse, and the published PRONOUNCE and GRADE trials. First, we examined the feasibility of implementing the baseline participant characteristics included in the published PRONOUNCE and GRADE trials' using real-world data and classified each variable as ascertainable, partially ascertainable, or not ascertainable. Second, we compared the emulated trials and published randomized controlled trials for baseline patient characteristics (concordance determined using standardized mean differences <0.20) and results of the primary and secondary endpoints (concordance determined by direction of effect estimates and statistical significance).

RESULTS

The PRONOUNCE trial enrolled 544 participants, and the emulated trial included 2226 propensity score-matched participants. In the PRONOUNCE trial publication, one of the 32 baseline participant characteristics was listed as an exclusion criterion on ClinicalTrials.gov but was ultimately not used. Among the remaining 31 characteristics, 9 (29.0%) were ascertainable, 11 (35.5%) were partially ascertainable, and 10 (32.2%) were not ascertainable using structured data from OptumLabs. For one additional variable, the PRONOUNCE trial did not provide sufficient detail to allow its ascertainment. Of the nine variables that were ascertainable, values in the emulated trial and published randomized controlled trial were discordant for 6 (66.7%). The primary endpoint of time from randomization to the first major adverse cardiovascular event and secondary endpoints of nonfatal myocardial infarction and stroke were concordant between the emulated trial and published randomized controlled trial. The GRADE trial enrolled 5047 participants, and the emulated trial included 7540 participants. In the GRADE trial publication, 8 of 34 (23.5%) baseline participant characteristics were ascertainable, 14 (41.2%) were partially ascertainable, and 11 (32.4%) were not ascertainable using structured data from OptumLabs. For one variable, the GRADE trial did not provide sufficient detail to allow for ascertainment. Of the eight variables that were ascertainable, values in the emulated trial and published randomized controlled trial were discordant for 4 (50.0%). The primary endpoint of time to hemoglobin A1c ≥7.0% was mostly concordant between the emulated trial and the published randomized controlled trial.

CONCLUSION

Despite challenges, observational methods and real-world data can be leveraged in certain important situations for a more timely evaluation of drug effectiveness and safety in more diverse and representative patient populations.

Propensity score-matched analysis of enhanced recovery after surgery in total hip arthroplasty for displaced femoral neck fractures

OBJECTIVE

The concept of enhanced recovery after surgery (ERAS) has been proposed in recent years, which indeed bring about evident convenience for the patients. This prospective cohort study was aimed to investigate the impact of ERAS on the clinical outcome of patients who undergoing total hip arthroplasty due to displaced femoral neck fractures.

METHODS

Patients in two periods were included in our research, before ERAS (n = 194) and after ERAS (n = 65). The clinical outcome, such as patient statistics, details of perioperative management, length of stay (LOS), pain, Harris hip score, in-hospital complications, and interim postoperative survival were collected. This retrospective observational study addressed confounding bias using propensity score matching (PSM) analysis.

RESULTS

With PSM, 55 pairs of well-matched patients were generated for comparison (conventional vs. ERAS). LOS decreased to 13.0 ± 3.2 days for the ERAS group, compared to 15.7 ± 3.5 days in the conventional group. VAS pain scores decreased significantly in both groups, and the decrease in the ERAS group was more significant than that in the conventional group at 3, 7, and 14 days postoperatively. The Harris scores of both groups significantly improved, but were better for the ERAS group than the conventional group at 7 and 14 days and 1 month postoperatively. However, no significant difference was observed at 6 months postoperatively. Additionally, the incidence of complications during hospitalization was lower in the ERAS group than that in the conventional group. No significant difference was observed in the medium-term survival between the two groups.

CONCLUSIONS

ERAS apparently benefit patients in early rehabilitation by reducing complications and shortening hospital stays but not for the long-term hip function or survival.

Sublobar resection versus lobectomy for stage IA non-small-cell lung cancer ≤ 2 cm: a systematic review and patient-level meta-analysis

Despite lobectomy being the standard of care for early-stage non-small-cell lung cancer (NSCLC), sublobar resection (segmentectomy or wedge resection) has recently been suggested to achieve similar outcomes. An electronic literature search was conducted to retrieve randomized controlled trials (RCTs) or propensity score-matched studies (PSMs) comparing lobectomy to sublobar resection in stage IA NSCLC ≤ 2 cm in size, with provision of Kaplan-Meier curves for overall survival (OS) and disease-free survival (DFS). A graphical reconstructive algorithm was used to obtain OS and DFS of individual patients, which was then pooled under random-effects individual patient data meta-analysis using Cox models to determine hazard ratios (HRs). Sensitivity analyses for OS and DFS were also performed, restricting to results from RCTs only. Seven studies (2528 patients) were retrieved. There were no significant differences in OS (shared-frailty HR = 0.92, 95% CI = 0.77-1.11, p = 0.378) or DFS (shared-frailty HR = 1.06, 95% CI = 0.90-1.24, p = 0.476) between lobectomy and sublobar resection. This comparison remained non-significant even when restricted to RCTs only. Pooled Kaplan-Meier curves of OS appeared to diverge over time, in favor of sublobar resection. This was confirmed on analysis of restricted mean survival time curves. This patient-level meta-analysis of high-quality studies demonstrates that sublobar resection is equivalent to lobectomy in patients with small stage IA NSCLC. Sublobar resection offers greater down-the-road benefits in patients who experience recurrence or a second primary tumor since the lung-sparing index surgery allows patients to receive further treatment safely. This heralds sublobar resection as the new standard of care in carefully selected early-stage patients.Trial registration: PROSPERO CRD42023385358.

Long-Term Outcomes of Open Versus Endovascular Treatment for Abdominal Aortic Aneurysm: Systematic Review and Meta-Analysis With Reconstructed Time-to-Event Data

BACKGROUND

The advent of endovascular techniques has revolutionized the care of patients with uncomplicated abdominal aortic aneurysms. This analysis compares the overall survival and the freedom from reintervention rate between open surgical repair (OSR) and endovascular repair (EVAR) in patients undergoing elective abdominal aortic aneurysm (AAA) repair.

METHODS

PubMed, Scopus, and Cochrane databases were searched for studies including patients who underwent either OSR or EVAR for uncomplicated AAA. All randomized controlled trials and propensity-score-matched cohort studies reporting on the outcomes of interest were considered eligible for inclusion. The systematic search of the literature was performed by 2 independent investigators in accordance with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. We conducted 1-stage and 2-stage meta-analyses with Kaplan-Meier-derived time-to-event data and meta-analysis with a random-effects model.

RESULTS

Thirteen studies met our eligibility criteria, incorporating 13 409 and 13 450 patients in the OSR and EVAR arms, respectively. Patients who underwent open repair had improved overall survival rates compared with those who underwent EVAR (hazard ratio [HR]=0.93, 95% confidence interval [CI]=0.88-0.98, p=0.004) during a mean follow-up of 53.8 (SD=29.8) months and this was validated by the 2-stage meta-analysis (HR=0.89, 95% CI=0.8-0.99, p=0.03, I2=62.25%). Splitting timepoint analysis suggested that EVAR offers better survival outcome compared with OSR in the first 11 months following elective intervention (HR=1.37, 95% CI=1.22-1.54, p<0.0001), while OSR offers a significant survival advantage after the 11-month timepoint and up to 180 months (HR=0.84, 95% CI=0.8-0.89, p<0.0001). Similarly, freedom from reintervention was found to be significantly better in EVAR patients (HR=1.28, 95% CI=1.14-1.44, p<0.0001) within the first 30 days. After the first month postrepair, however, OSR demonstrated higher freedom-from-reintervention rates compared with EVAR that remained significant for up to 168 months during follow-up (HR=0.73, 95% CI=0.66-0.79, p<0.0001).

CONCLUSIONS

Despite the first-year survival advantage of EVAR in patients undergoing elective AAA repair, OSR was associated with a late survival benefit and decreased risk for reintervention in long-term follow-up.

CLINICAL IMPACT

Open surgical repair for uncomplicated abdominal aortic aneurysm offers better long-term outcomes in terms of survival and freedom from reintervention rate compared to the endovascular approach but in the first year it carries a higher risk of mortality. The novelty of our study lies that instead of comparing study-level effect estimates, we analyzed reconstructed individual patient-level data. This offered us the opportunity to perform our analyses with mathematically robust and flexible survival models, which was proved to be crucial since there was evidence of different hazard over time. Our findings underline the need for additional investigation to clarify the significance of open surgical repair when compared to the latest endovascular devices and techniques within the evolving era of minimally invasive procedures.

Mapping research trends of transarterial chemoembolization for hepatocellular carcinoma from 2012 to 2021: A bibliometric analysis

BACKGROUND

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the second leading cause of cancer-related deaths. Transcatheter arterial chemoembolization (TACE) is a therapy where drugs aimed to slow or halt tumor development are injected into the artery supplying for HCC tissues. A comprehensive analysis of all the articles on TACE for HCC can give us a general understanding of the progress in this field and provide guidance for future research.

AIM

To analyze and visualize scientific results and research trends in TACE treatment for HCC.

METHODS

The "Web of Science" database was used to identify articles regarding TACE for the treatment of HCC from 2012 to 2021. VOSviewer and CiteSpace were used to analyze the publications trends, collaboration between countries/insti-tutions/authors, and the co-occurrence of keywords, keyword bursts, and references.

RESULTS

A total of 5728 original articles on TACE for HCC were retrieved. Regarding the volume of publications, the total number of yearly publications showed a generally increasing trend. China had the highest number of articles, while the United States achieved the highest Hirsch index and highest number of citations. The Sun Yat-sen University in China was most prolific institution. The most active author was Park, J.W from South Korea. The Journal of Vascular and Interventional Radiology (234 articles) was the most productive journal. There is a growing trend toward international collaboration in TACE for HCC. Cluster networks of co-cited references suggested that practice guidelines and targeted therapies are an essential theme in this field. In addition, cluster analysis based on keyword co-occurrence identified the research topic "prediction of TACE treatment" as a hotspot, and propensity score matching can be used to help investigators conduct innovative studies in the future.

CONCLUSION

The results of our bibliometric analysis provide the latest trends and hot topics in TACE therapy for HCC.

Network Meta-Analysis Comparing Transcatheter, Minimally Invasive, and Conventional Surgical Aortic Valve Replacement

The landscape of aortic valve replacement (AVR) has evolved dramatically over the years, but time-varying outcomes have yet to be comprehensively explored. This study aimed to compare the all-cause mortality among 3 AVR techniques: transcatheter (TAVI), minimally invasive (MIAVR), and conventional AVR (CAVR). An electronic literature search was performed for randomized controlled trials (RCTs) comparing TAVI with CAVR and RCTs or propensity score-matched (PSM) studies comparing MIAVR with CAVR or MIAVR to TAVI. Individual patient data for all-cause mortality were derived from graphical reconstruction of Kaplan-Meier curves. Pairwise comparisons and network meta-analysis were conducted. Sensitivity analyses were performed in the TAVI arm for high risk and low/intermediate risk, as well as patients who underwent transfemoral (TF) TAVI. A total of 27 studies with 16,554 patients were included. In the pairwise comparisons, TAVI showed superior mortality to CAVR until 37.5 months, beyond which there was no significant difference. When restricted to TF TAVI versus CAVR, a consistent mortality benefit favoring TF TAVI was seen (shared frailty hazard ratio [HR] = 0.86, 95% confidence interval [CI] = 0.76 to 0.98, p = 0.024). In the network meta-analysis involving majority PSM data, MIAVR demonstrated significantly lower mortality than TAVI (HR = 0.70, 95% CI = 0.59 to 0.82) and CAVR (HR = 0.69, 95% CI = 0.59 to 0.80); this association remained compared with TF TAVI but with a lower extent of benefit (HR = 0.80, 95% CI = 0.65 to 0.99). In conclusion, the initial short- to medium-term mortality benefit for TAVI over CAVR was attenuated over the longer term. In the subset of patients who underwent TF TAVI, a consistent benefit was found. Among majority PSM data, MIAVR showed improved mortality compared with TAVI and CAVR but less than the TF TAVI subset, which requires validation by robust RCTs.

Perforated peptic ulcer (PPU) treatment: an Italian nationwide propensity score-matched cohort study investigating laparoscopic vs open approach

BACKGROUND

Perforated peptic ulcer (PPU) remain a surgical emergency accounting for 37% of all peptic ulcer-related deaths. Surgery remains the standard of care. The benefits of laparoscopic approach have been well-established even in the elderly. However, because of inconsistent results with specific regard to some technical aspects of such technique surgeons questioned the adoption of laparoscopic approach. This leads to choose the type of approach based on personal experience. The aim of our study was to critically appraise the use of the laparoscopic approach in PPU treatment comparing it with open procedure.

METHODS

A retrospective study with propensity score matching analysis of patients underwent surgical procedure for PPU was performed. Patients undergoing PPU repair were divided into: Laparoscopic approach (LapA) and Open approach (OpenA) groups and clinical-pathological features of patients in the both groups were compared.

RESULTS

A total of 453 patients underwent PPU simple repair. Among these, a LapA was adopted in 49% (222/453 patients). After propensity score matching, 172 patients were included in each group (the LapA and the OpenA). Analysis demonstrated increased operative times in the OpenA [OpenA: 96.4 ± 37.2 vs LapA 88.47 ± 33 min, p = 0.035], with shorter overall length of stay in the LapA group [OpenA 13 ± 12 vs LapA 10.3 ± 11.4 days p = 0.038]. There was no statistically significant difference in mortality [OpenA 26 (15.1%) vs LapA 18 (10.5%), p = 0.258]. Focusing on morbidity, the overall rate of 30-day postoperative morbidity was significantly lower in the LapA group [OpenA 67 patients (39.0%) vs LapA 37 patients (21.5%) p = 0.002]. When stratified using the Clavien-Dindo classification, the severity of postoperative complications was statistically different only for C-D 1-2.

CONCLUSIONS

Based on the present study, we can support that laparoscopic suturing of perforated peptic ulcers, apart from being a safe technique, could provide significant advantages in terms of postoperative complications and hospital stay.

Effect of 2D vs. 3D laparoscopy on postoperative complications and operation time in a propensity-score-matched real-world data analysis

BACKGROUND

Postoperative complication rates using 3D visualization are rarely reported. The primary aim of our study is to detect a possible advantage of using 3D on postoperative complication rates in a real-world setting.

METHOD

With a sample size calculation for a medium effect size difference that 3D reduces significantly postoperative complications, data of 287 patients with 3D visualization and 832 with 2D procedure were screened. The groups underwent an exact propensity score-matching to be comparable. Comprehensive complication index (CCI) for every procedure was calculated and Operation Time was determined.

RESULTS

Including 1078 patients in the study, 213 exact propensity score-matched pairs could finally be established. Concerning overall CCI (3D: 5.70 ± 13.63 vs. 2D: 3.37 ± 9.89; p = 0.076) and operation time (3D: 103.98 ± 93.26 min vs. 2D: 88.60 ±6 9.32 min; p = 0.2569) there was no significant difference between the groups.

CONCLUSION

Our study shows no advantage of 3D over 2D laparoscopy regarding postoperative complications in a real-world setting, the second endpoint operation time, too, was not influenced by 3D overall.

Comparison of Postoperative Outcome and Prognosis Among Laparoscopic Left Colectomy and Laparoscopic Sigmoidectomy in Sigmoid Colon Cancer Patients: A Propensity Score Matching Study

PURPOSE

The purpose of this study was to investigate the effect of laparoscopic left colectomy (LLC) and laparoscopic sigmoidectomy (LSD) on short-term outcomes and prognosis of sigmoid colon cancer (SCC) patients using propensity score matching (PSM).

METHODS

In this retrospective study, the SCC patients who underwent LLC or LSD surgery were collected from a single clinical center from Jan 2011 to Dec 2019. Short-term outcomes and prognosis were compared between patients who received LSD surgery and LLC surgery.

RESULTS

A total of 356 patients were included in this study. After 1:1 PSM analysis, there were 50 patients who underwent LLC surgery and 50 patients who underwent LSD surgery left in this study. No significant difference was found in baseline characteristics after PSM (P > .05). In comparison with the LLC surgery group, the LSD surgery group had shorter operation time (P = .003) after PSM. Moreover, the surgical procedure was not an independent predictor for overall survival (OS) (P = .918, 95% CI = .333-2.688) and disease-free survival DFS (P = .730, 95% CI = .335-2.150), but age (OS: P = .009, 95% CI = 1.010-1.075; DFS: P = .014, 95% CI = 1.007-1.061) and tumor stage (OS: P = .004, 95% CI = 1.302-3.844; DFS: P < .01, 95% CI = 1.572-4.171) were the independent risk factors for OS and DFS in SCC patients.

CONCLUSION

There was no significant difference between the two surgical procedures for prognosis of SCC patients. However, the possible reasons for changing the surgical procedures should be cautious by surgeons.

External control arm analysis: an evaluation of propensity score approaches, G-computation, and doubly debiased machine learning

BACKGROUND

An external control arm is a cohort of control patients that are collected from data external to a single-arm trial. To provide an unbiased estimation of efficacy, the clinical profiles of patients from single and external arms should be aligned, typically using propensity score approaches. There are alternative approaches to infer efficacy based on comparisons between outcomes of single-arm patients and machine-learning predictions of control patient outcomes. These methods include G-computation and Doubly Debiased Machine Learning (DDML) and their evaluation for External Control Arms (ECA) analysis is insufficient.

METHODS

We consider both numerical simulations and a trial replication procedure to evaluate the different statistical approaches: propensity score matching, Inverse Probability of Treatment Weighting (IPTW), G-computation, and DDML. The replication study relies on five type 2 diabetes randomized clinical trials granted by the Yale University Open Data Access (YODA) project. From the pool of five trials, observational experiments are artificially built by replacing a control arm from one trial by an arm originating from another trial and containing similarly-treated patients.

RESULTS

Among the different statistical approaches, numerical simulations show that DDML has the smallest bias followed by G-computation. In terms of mean squared error, G-computation usually minimizes mean squared error. Compared to other methods, DDML has varying Mean Squared Error performances that improves with increasing sample sizes. For hypothesis testing, all methods control type I error and DDML is the most conservative. G-computation is the best method in terms of statistical power, and DDML has comparable power at [Formula: see text] but inferior ones for smaller sample sizes. The replication procedure also indicates that G-computation minimizes mean squared error whereas DDML has intermediate performances in between G-computation and propensity score approaches. The confidence intervals of G-computation are the narrowest whereas confidence intervals obtained with DDML are the widest for small sample sizes, which confirms its conservative nature.

CONCLUSIONS

For external control arm analyses, methods based on outcome prediction models can reduce estimation error and increase statistical power compared to propensity score approaches.

Propensity score-matched analysis comparing retrograde intrarenal surgery with percutaneous nephrolithotomy in anomalous kidneys

BACKGROUND

Endourologic interventions for urolithiasis in patients with anomalous kidneys can be challenging, and comparisons between these interventions are not well studied. We aim to compare the safety, outcomes and complications of retrograde intrarenal surgery (RIRS) versus percutaneous nephrolithotomy (PCNL) in patients with urolithiasis in anomalous kidneys.

METHODS

A propensity score-matched pair analysis (PSM) was performed on pooled patient data from 20 centers. 569 patients with anomalous kidneys (horseshoe kidney [HSK], ectopic kidney, malrotated kidney) and urolithiasis who received either PCNL or RIRS as the primary modality of intervention from 2010 to 2020 were analyzed. Patients were matched based on calculated propensity scores by a regression model using age, sex, comorbidities, stone size, and renal anomaly type as co-variates. Multivariate logistic regression of factors (mode of treatment [PCNL or RIRS], comorbidities, stone size) and their effects on outcomes of stone-free rate (SFR), need to abandon surgery due to intraoperative difficulty, postoperative hematuria and sepsis and were analyzed when applicable.

RESULTS

After PSM, there were a total of 127 pairs in each group. Overall, PCNL conferred a higher SFR compared to RIRS (OR=3.69, 95% CI 1.91-7.46, P<0.001), particularly in HSK (OR=3.33, 95% CI 1.22-9.99, P=0.023), and ectopic kidneys (OR=18.10, 95% CI 3.62-147.63, P=0.002), with no significant difference in malrotated kidneys. There was no significant difference in postoperative sepsis observed. Surgery was abandoned more often in RIRS than PCNL (6.3% vs. 0%, P=0.014). Although PSM provides a robust analysis due to baseline differences in the unmatched cohorts, this study was limited by an inevitable degree of selection bias.

CONCLUSIONS

While both modalities are safe and efficacious, PCNL yields better SFR than RIRS in patients with anomalous kidneys, with no difference in postoperative sepsis rates. Patients may benefit from personalized management best carried out in high volume endourology centers.

Comparison Between Minimally Invasive Right Anterior and Right Posterior Sectionectomy vs Right Hepatectomy: An International Multicenter Propensity Score-Matched and Coarsened-Exact-Matched Analysis of 1,100 Patients

BACKGROUND

The role of minimally invasive right anterior and right posterior sectionectomy (MI-RAS/MI-RPS) for right-sided liver lesions remains debatable. Although technically more demanding, these procedures might result in faster recovery and lower postoperative morbidity compared with minimally invasive right hemihepatectomy.

STUDY DESIGN

This is an international multicenter retrospective analysis of 1,114 patients undergoing minimally invasive right hemihepatectomy, MI-RAS, and MI-RPS at 21 centers between 2006 and 2019. Minimally invasive surgery included pure laparoscopic, robotic, hand-assisted, or a hybrid approach. A propensity-matched and coarsened-exact-matched analysis was performed.

RESULTS

A total of 1,100 cases met study criteria, of whom 759 underwent laparoscopic, 283 robotic, 11 hand-assisted, and 47 laparoscopic-assisted (hybrid) surgery. There were 632 right hemihepatectomies, 373 right posterior sectionectomies, and 95 right anterior sectionectomies. There were no differences in baseline characteristics after matching. In the MI-RAS/MI-RPS group, median blood loss was higher (400 vs 300 mL, p = 0.001) as well as intraoperative blood transfusion rate (19.6% vs 10.7%, p = 0.004). However, the overall morbidity rate was lower including major morbidity (7.1% vs 14.3%, p = 0.007) and reoperation rate (1.4% vs 4.6%, p = 0.029). The rate of close/involved margins was higher in the MI-RAS/MI-RPS group (23.4% vs 8.9%, p < 0.001). These findings were consistent after both propensity and coarsened-exact matching.

CONCLUSIONS

Although technically more demanding, MI-RAS/MI-RPS is a valuable alternative for minimally invasive right hemihepatectomy in right-sided liver lesions with lower postoperative morbidity, possibly due to the preservation of parenchyma. However, the rate of close/involved margins is higher in these procedures. These findings might guide surgeons in preoperative counselling and in selecting the appropriate procedure for their patients.

Laparoscopic versus open liver resection for hepatocellular carcinoma in elderly patients: A systematic review and meta-analysis of propensity score-matched studies

Purpose

Laparoscopic liver resection (LLR) is a widely practiced therapeutic method and holds several advantages over open liver resection (OLR) including less postoperative pain, lower morbidity, and faster recovery. However, the effect of LLR for the treatment of hepatocellular carcinoma (HCC) in elderly patients remains controversial. Therefore, we aimed to perform the first meta-analysis of propensity score-matched (PSM) studies to compare the short- and long-term outcomes of LLR versus OLR for elderly patients with HCC.

Methods

Databases including PubMed, Embase, Scopus, and Cochrane Library were systematically searched until April 2022 for eligible studies that compared LLR and OLR for the treatment of HCC in elderly patients. Short-term outcomes include postoperative complications, blood loss, surgical time, and length of hospital stay. Long-term outcomes include overall survival (OS) rate and disease-free survival (DFS) rate at 1, 3, and 5 years.

Results

A total of 12 trials involving 1,861 patients (907 in the LLR group, 954 in the OLR group) were included. Compared with OLR, LLR was associated with lower postoperative complications (OR 0.49, 95% CI 0.39 to 0.62, P &lt; 0.00001, I2 = 0%), less blood loss (MD −285.69, 95% CI −481.72 to −89.65, P = 0.004, I2 = 96%), and shorter hospital stay (MD −7.88, 95% CI −11.38 to −4.37, P &lt; 0.0001, I2 = 96%), whereas operation time (MD 17.33, 95% CI −6.17 to 40.83, P = 0.15, I2 = 92%) was insignificantly different. Furthermore, there were no significant differences for the OS and DFS rates at 1, 3, and 5 years.

Conclusions

For elderly patients with HCC, LLR offers better short-term outcomes including a lower incidence of postoperative complications and shorter hospital stays, with comparable long-term outcomes when compared with the open approach. Our results support the implementation of LLR for the treatment of HCC in elderly patients.

Systematic review registration

https://inplasy.com/inplasy-2022-4-0156/, identifier INPLASY202240156.

A Systematic Review of Propensity Score Matching in the Orthopedic Literature

Background

Propensity score matching (PSM) is a statistical technique used to reduce bias in observational studies by controlling for measured confounders. Given its complexity and popularity, it is imperative that researchers comprehensively report their methodologies to ensure accurate interpretation and reproducibility.

Purpose

This systematic review sought to define how often PSM has been used in recent orthopedic research and to describe how such studies reported their methods. Secondary aims included analyzing study reproducibility, bibliometric factors associated with reproducibility, and associations between methodology and the reporting of statistically significant results.

Methods

PubMed and Embase databases were queried for studies containing "propensity score" and "match*" published in 20 orthopedic journals prior to 2020. All studies meeting inclusion criteria were used for trend analysis. Articles published between 2017 and 2019 were used for analysis of reporting quality and reproducibility.

Results

In all, 261 studies were included for trend analysis, and 162 studies underwent full-text review. The proportion of orthopedic studies using PSM significantly increased over time. Seventy-one (41%) articles did not provide justification for covariate selection. The majority of studies illustrated covariate balance through P values. We found that 19% of the studies were fully reproducible. Most studies failed to report the use of replacement (67.3%) or independent or paired statistical methods (34.0%). Studies reporting standardized mean differences to illustrate covariate balance were less likely to report statistically significant results.

Conclusion

Despite the increased use of PSM in orthopedic research, observational studies employing PSM have largely failed to adequately report their methodology.

Limited liver resections in the posterosuperior segments: international multicentre propensity score-matched and coarsened exact-matched analysis comparing the laparoscopic and robotic approaches

Background

Limited liver resections (LLRs) for tumours located in the posterosuperior segments of the liver are technically demanding procedures. This study compared outcomes of robotic (R) and laparoscopic (L) LLR for tumours located in the posterosuperior liver segments (IV, VII, and VIII).

Methods

This was an international multicentre retrospective analysis of patients who underwent R-LLR or L-LLR at 24 centres between 2010 and 2019. Patient demographics, perioperative parameters, and postoperative outcomes were analysed; 1 : 3 propensity score matching (PSM) and 1 : 1 coarsened exact matching (CEM) were performed.

Results

Of 1566 patients undergoing R-LLR and L-LLR, 983 met the study inclusion criteria. Before matching, 159 R-LLRs and 824 L-LLRs were included. After 1 : 3 PSM of 127 R-LLRs and 381 L-LLRs, comparison of perioperative outcomes showed that median blood loss (100 (i.q.r. 40–200) versus 200 (100–500) ml; P = 0.003), blood loss of at least 500 ml (9 (7.4 per cent) versus 94 (27.6 per cent); P &lt; 0.001), intraoperative blood transfusion rate (4 (3.1 per cent) versus 38 (10.0 per cent); P = 0.025), rate of conversion to open surgery (1 (0.8 per cent) versus 30 (7.9 per cent); P = 0.022), median duration of Pringle manoeuvre when applied (30 (20–46) versus 40 (25–58) min; P = 0.012), and median duration of operation (175 (130–255) versus 224 (155–300); P &lt; 0.001) were lower in the R-LLR group compared with the L-LLR group. After 1 : 1 CEM of 104 R-LLRs with 104 L-LLRs, R-LLR was similarly associated with significantly reduced blood loss and a lower rate of conversion to open surgery.

Conclusion

Based on a matched analysis of well selected patients, both robotic and laparoscopic access could be undertaken safely with good outcomes for tumours in the posterosuperior liver segments.

Comparison of Efficacy and Safety Between Laparoscopic and Open Radical Resection for Hilar Cholangiocarcinoma—A Propensity Score-Matching Analysis

Background

Radical resection remains the most effective treatment for hilar cholangiocarcinoma (HCCA). However, due to the complex anatomy of the hilar region, the tumor is prone to invade portal vein and hepatic arteries, making the surgical treatment of HCCA particularly difficult. Successful laparoscopic radical resection of HCCA(IIIA, IIIB) requires excellent surgical skills and rich experience. Furthermore, the safety and effectiveness of this operation are still controversial.

Aim

To retrospectively analyze and compare the efficacy and safety of laparoscopic and open surgery for patients with HCCA.

Methods

Clinical imaging and postoperative pathological data of 89 patients diagnosed with HCCA (IIIA, IIIB) and undergoing radical resection in our center from January 2018 to March 2022 were retrospectively analyzed. Among them, 6 patients (4 were lost to follow-up and 2 were pathologically confirmed to have other diseases after surgery) were ruled out, and clinical data was collected from the remaining 83 patients for statistical analysis. These patients were divided into an open surgery group (n=62) and a laparoscopic surgery group (n=21) according to the surgical methods used, and after 1:2 propensity score matching (PSM), 32 and 16 patients respectively in the open surgery group and laparoscopic surgery group were remained. The demographic data, Bismuth type, perioperative data, intraoperative data, postoperative complications, pathological findings, and long-term survivals were compared between these two groups.

Results

After 1:2 PSM, 32 patients in the open surgery group and 16 patients in the laparoscopic surgery group were included for further analysis. Baseline characteristics and pathological outcomes were comparable between the two groups. Statistically significant differences between the two groups were observed in intraoperative blood loss and operative time, as it were 400-800 mL vs 200-400 mL (P=0.012) and (407.97 ± 76.06) min vs (489.69 ± 79.17) min (P=0.001) in the open surgery group and laparoscopic surgery group, respectively. The R0 resection rate of the open group was 28 cases (87.5%), and the R0 resection rate of the laparoscopic group was 15 cases (93.75%). The two groups showed no significant difference in terms of surgical approach, intraoperative blood transfusion, incidence of postoperative complications, and short- and long-term efficacy (P&gt;0.05).

Conclusions

Laparoscopic radical resection of HCCA has comparable perioperative safety compared to open surgery group, as it has less bleeding and shorter operation time. Although it is a promising procedure with the improvement of surgical skills and further accumulation of experience, further investigations are warranted before its wider application.

Propensity-score matched analysis to evaluate efficacy of endoscopic submucosal dissection for superficial esophageal cancer in gastrectomized patients

Endoscopic submucosal dissection (ESD) is a minimally invasive treatment option for superficial esophageal cancer (SEC) with high rates of complete resection. However, limited research exists on the efficacy of ESD for SEC in gastrectomized patients. This study aimed to evaluate the efficacy of ESD for SEC in gastrectomized patients. We included 318 patients of SEC treated at our institution between April 2005 and October 2021. To minimize bias between the gastrectomized and non-gastrectomized groups, we conducted a propensity-score matched analysis and compared the ESD outcomes for SEC of the two groups. Of the 318 patients included in the study, 48 and 270 patients were in the gastrectomized and non-gastrectomized groups, respectively. After 1:2 propensity-score matching, we matched 44 patients in the gastrectomized group to 88 patients in the non-gastrectomized group, and found no significant differences in the baseline clinicopathological characteristics. Regarding the ESD outcomes, there were no significant differences in the complete resection rate, procedure time, hospitalized period, and recurrence rates between the two groups. Multivariate analysis also cofirmed that the history of gastrectomy was not a risk factor of the difficult case of esophageal ESD. In conclusion, history of gastrectomy might not negatively affect the ESD outcomes of SECs.

Subcutaneous Versus Transvenous Implantable Defibrillator Therapy: A Systematic Review and Meta-Analysis of Randomized Trials and Propensity Score-Matched Studies

Background

Subcutaneous implantable cardioverter‐defibrillators (S‐ICDs) have been of great interest as an alternative to transvenous implantable cardioverter‐defibrillators (TV‐ICDs). No meta‐analyses synthesizing data from high‐quality studies have yet been published.

Methods and Results

An electronic literature search was conducted to retrieve randomized controlled trials or propensity score–matched studies comparing S‐ICD against TV‐ICD in patients with an implantable cardioverter‐defibrillator indication. The primary outcomes were device‐related complications and lead‐related complications. Secondary outcomes were inappropriate shocks, appropriate shock, all‐cause mortality, and infection. All outcomes were pooled under random‐effects meta‐analyses and reported as risk ratios (RRs) and 95% CIs. Kaplan–Meier curves of device‐related complications were digitized to retrieve individual patient data and pooled under a 1‐stage meta‐analysis using Cox models to determine hazard ratios (HRs) of patients undergoing S‐ICD versus TV‐ICD. A total of 5 studies (2387 patients) were retrieved. S‐ICD had a similar rate of device‐related complications compared with TV‐ICD (RR, 0.59 [95% CI, 0.33–1.04]; P=0.070), but a significantly lower lead‐related complication rate (RR, 0.14 [95% CI, 0.07–0.29]; P<0.0001). The individual patient data–based 1‐stage stratified Cox model for device‐related complications across 4 studies yielded no significant difference (shared‐frailty HR, 0.82 [95% CI, 0.61–1.09]; P=0.167), but visual inspection of pooled Kaplan–Meier curves suggested a divergence favoring S‐ICD. Secondary outcomes did not differ significantly between both modalities.

Conclusions

S‐ICD is clinically superior to TV‐ICD in terms of lead‐related complications while demonstrating comparable efficacy and safety. For device‐related complications, S‐ICD may be beneficial over TV‐ICD in the long term. These indicate that S‐ICD is likely a suitable substitute for TV‐ICD in patients requiring implantable cardioverter‐defibrillator implantation without a pacing indication.

Translating cell therapies for neurodegenerative diseases: Huntington's disease as a model disorder

There has been substantial progress in the development of regenerative medicine strategies for CNS disorders over the last decade, with progression to early clinical studies for some conditions. However, there are multiple challenges along the translational pipeline, many of which are common across diseases and pertinent to multiple donor cell types. These include defining the point at which the preclinical data are sufficiently compelling to permit progression to the first clinical studies; scaling-up, characterization, quality control and validation of the cell product; design, validation and approval of the surgical device; and operative procedures for safe and effective delivery of cell product to the brain. Furthermore, clinical trials that incorporate principles of efficient design and disease-specific outcomes are urgently needed (particularly for those undertaken in rare diseases, where relatively small cohorts are an additional limiting factor), and all processes must be adaptable in a dynamic regulatory environment. Here we set out the challenges associated with the clinical translation of cell therapy, using Huntington's disease as a specific example, and suggest potential strategies to address these challenges. Huntington's disease presents a clear unmet need, but, importantly, it is an autosomal dominant condition with a readily available gene test, full genetic penetrance and a wide range of associated animal models, which together mean that it is a powerful condition in which to develop principles and test experimental therapeutics. We propose that solving these challenges in Huntington's disease would provide a road map for many other neurological conditions. This white paper represents a consensus opinion emerging from a series of meetings of the international translational platforms Stem Cells for Huntington's Disease and the European Huntington's Disease Network Advanced Therapies Working Group, established to identify the challenges of cell therapy, share experience, develop guidance and highlight future directions, with the aim to expedite progress towards therapies for clinical benefit in Huntington's disease.

Evaluating agreement between bodies of evidence from randomized controlled trials and cohort studies in medical research: a meta-epidemiological study

BACKGROUND

Randomized controlled trials (RCTs) and cohort studies are the most common study design types used to assess the treatment effects of medical interventions. To evaluate the agreement of effect estimates between bodies of evidence (BoE) from randomized controlled trials (RCTs) and cohort studies and to identify factors associated with disagreement.

METHODS

Systematic reviews were published in the 13 medical journals with the highest impact factor identified through a MEDLINE search. BoE-pairs from RCTs and cohort studies with the same medical research question were included. We rated the similarity of PI/ECO (Population, Intervention/Exposure, Comparison, Outcome) between BoE from RCTs and cohort studies. The agreement of effect estimates across BoE was analyzed by pooling ratio of ratios (RoR) for binary outcomes and difference of mean differences for continuous outcomes. We performed subgroup analyses to explore factors associated with disagreements.

RESULTS

One hundred twenty-nine BoE pairs from 64 systematic reviews were included. PI/ECO-similarity degree was moderate: two BoE pairs were rated as "more or less identical"; 90 were rated as "similar but not identical" and 37 as only "broadly similar". For binary outcomes, the pooled RoR was 1.04 (95% CI 0.97-1.11) with considerable statistical heterogeneity. For continuous outcomes, differences were small. In subgroup analyses, degree of PI/ECO-similarity, type of intervention, and type of outcome, the pooled RoR indicated that on average, differences between both BoE were small. Subgroup analysis by degree of PI/ECO-similarity revealed high statistical heterogeneity and wide prediction intervals across PI/ECO-dissimilar BoE pairs.

CONCLUSIONS

On average, the pooled effect estimates between RCTs and cohort studies did not differ. Statistical heterogeneity and wide prediction intervals were mainly driven by PI/ECO-dissimilarities (i.e., clinical heterogeneity) and cohort studies. The potential influence of risk of bias and certainty of the evidence on differences of effect estimates between RCTs and cohort studies needs to be explored in upcoming meta-epidemiological studies.

Tenets for the Proper Conduct and Use of Meta-Analyses: A Practical Guide for Neurosurgeons

Neurosurgeons today are inundated with rapidly amassing neurosurgical research publications. Systematic reviews and meta-analyses have consequently surged in popularity because, when executed properly, they constitute a high level of evidence and may save busy neurosurgeons many hours of combing and reviewing the literature for relevant articles. Meta-analysis refers to the quantitative (and discretionary) component of systematic reviews. It involves applying statistical techniques to combine effect sizes from multiple studies, which might offer more actionable insights than a systematic review without meta-analysis. Well-executed meta-analyses may prove instructive for clinical practice, but poorly conducted ones sow confusion and have the potential to cause harm. Unfortunately, recent audits have found the conduct and reporting of meta-analyses in neurosurgery (but also other surgical disciplines) to be relatively lackluster in methodologic rigor and compliance to established guidelines. Some of these deficiencies can be easily remedied through better awareness and adherence to prescribed standards-which will be reviewed in this article-but others stem from inherent problems with the source data (e.g., poor reporting of original research) as well as unique constraints faced by surgery as a field (e.g., lack of equipoise for randomized trials, or existence of learning curves for novel surgical procedures, which can lead to temporal heterogeneity), which may require unconventional tools (e.g., cumulative meta-analysis) to address. Therefore, it is also our goal to take stock of the unique issues encountered by surgeons who do meta-analysis and to highlight various techniques-some of which less well-known-to address such challenges.

Mechanical versus Bioprosthetic Valve for Aortic Valve Replacement: Systematic Review and Meta-Analysis of Reconstructed Individual Participant Data

OBJECTIVES

To compare biological versus mechanical aortic valve replacement.

METHODS

We searched MEDLINE, Scopus, and Cochrane Library databases for randomized clinical trials and propensity-score matched studies published by October 14th, 2021 according to PRISMA statement. Individual patient data on overall survival were extracted. One- and two-stage survival analyses, and random-effects meta-analyses were conducted.

RESULTS

25 studies were identified, incorporating 8,721 bioprosthetic and 8,962 mechanical valves:. In the one-stage meta-analysis, mechanical valves cumulatively demonstrated decreased hazard for mortality (Hazard Ratio [HR] : 0.79, 95% Confidence interval [CI] : 0.74-0.84, p < 0.0001). Overall survival was similar between the compared arms for patients <50 years old (HR: 0.88, 95% CI : 0.71-1.1, p = 0.216), increased in the mechanical valve arm for patients 50-70 years old (HR : 0.76, 95% CI : 0.70-0.83, p < 0.0001), and increased in the bioprosthetic arm for patients >70 years old (HR : 1.35, 95% CI : 1.17-1.57, p < 0.0001). Meta-regression analysis revealed that the survival in the 50-70 years old group was not influenced by the publication year of the individual studies. No statistically significant difference was observed regarding in-hospital mortality, post-operative strokes and post-operative reoperation. All-cause mortality was found decreased in the mechanical group, cardiac mortality was comparable between the two groups, major bleeding rates were increased in the mechanical valve group, and reoperation rates were increased in the bioprosthetic valve group.

CONCLUSIONS

Survival rates seem to not be influenced by the type of prosthesis in patients <50 years old. A survival advantage in favour of mechanical valves is observed in patients 50-70 years old, while in patients >70 years old bioprosthetic valves offer better survival outcomes.

The Effect of the Intraoperative Blood Loss and Intraoperative Blood Transfusion on the Short-Term Outcomes and Prognosis of Colorectal Cancer: A Propensity Score Matching Analysis

Purpose

The purpose of the current study was to analyze the effect of intraoperative blood loss (IBL) and intraoperative blood transfusion (IBT) on the short-term outcomes and prognosis for patients who underwent primary colorectal cancer (CRC) surgery.

Methods

We retrospectively collected the patients' information from the database of a teaching hospital from January 2011 to January 2020. IBL and IBT were collected and analyzed, and the propensity score matching (PSM) analysis was performed.

Results

A total of 4,250 patients with CRC were included in this study. There were 1,911 patients in the larger IBL group and 2,339 patients in the smaller IBL group. As for IBT, there were 82 patients in the IBT group and 4,168 patients in the non-IBT group. After 1:1 ratio PSM, there were 82 patients in the IBT group and 82 patients in the non-IBT group. The larger IBL group had longer operation time (p = 0.000 &lt; 0.01), longer post-operative hospital stay (p = 0.000 &lt; 0.01), smaller retrieved lymph nodes (p = 0.000 &lt; 0.01), and higher overall complication (p = 0.000 &lt; 0.01) than the smaller IBL group. The IBT group had longer operation time (p = 0.000 &lt; 0.01), longer hospital stay (p = 0.016 &lt; 0.05), and higher overall complications (p = 0.013 &lt; 0.05) compared with the non-IBT group in terms of short-term outcomes. Larger IBL (p = 0.000, HR = 1.352, 95% CI = 1.142–1.601) and IBT (p = 0.044, HR = 1.487, 95% CI = 1.011–2.188) were independent predictive factors of overall survival (OS). Larger IBL (p = 0.000, HR = 1.338, 95% CI = 1.150–1.558) was an independent predictor of disease-free survival (DFS); however, IBT (p = 0.179, HR = 1.300, 95% CI = 0.886–1.908) was not an independent predictor of DFS.

Conclusion

Based on the short-term outcomes and prognosis of IBL and IBT, surgeons should be cautious during the operation and more careful and proficient surgical skills are required for surgeons.

Effect of surgeon-related factors on outcome of retinal detachment surgery: analyses of data in Japan-retinal detachment registry

The purpose of this study was to investigate the effects of surgeon-related factors on the surgical outcome of pars plana vitrectomy (PPV) and scleral buckling (SB) surgery on eyes with a rhegmatogenous retinal detachment (RRD). This was a nationwide, multicenter, observational study of the data in the Japan-RD Registry. Registered cases that had undergone surgery for a RRD by 128 accredited surgeons in 26 institutions were studied. The surgeon-related factors that significantly affected surgical success and visual outcomes of simple RRD treated by PPV or SB at 6 months postoperatively were analyzed and compared. Among 3446 registered cases, 2533 cases met the inclusion criteria with 1896 in the PPV group and 637 cases in the SB group. The median total number of lifetime cases was 150 and the rate of surgeries/year was 22. Multivariate regression analyses showed that the number and rate of surgeries/year were not significantly associated with the surgical outcome in the PPV group. However, surgeons with a higher average annual number of surgeries had significantly better surgical outcomes in the SB group (P = 0.038). Analyses of a nationwide registry showed that SB but not PPV surgeries require sufficient experience and case numbers to acquire and maintain skills to treat RRDs successfully.

The Effect of Type 2 Diabetes Mellitus on the Short-Term Outcomes and Prognosis of Stage I–III Colorectal Cancer: A Propensity Score Matching Analysis

Purpose

The purpose of the current study was to analyze the effect of type 2 diabetes mellitus (T2DM) on the short-term outcomes and prognosis of stage I–III colorectal cancer (CRC) undergoing primary surgery.

Methods

Patients who underwent primary CRC surgery were retrospectively collected from Jan 2011 to Jan 2020 in a single clinical center. The short-term outcomes and prognosis were compared between T2DM group and non-T2DM group using propensity score matching (PSM) analysis.

Results

A total of 4250 patients were included in this study. There were 521 patients with T2DM and 3729 patients without T2DM. After 1:1 ratio PSM, there were 519 T2DM patients and 519 non-T2DM patients left in this study. No significant difference was found in baseline information after PSM (p>0.05). T2DM had higher overall complications (p=0.033) after PSM in terms of short-term outcomes. As for prognosis, T2DM group had worse overall survival (OS) in all stages (p=0.044), stage I (p=0.009) and stage II (p=0.021) of CRC and T2DM group had worse disease-free survival (DFS) than non-T2DM group in stage I (p=0.008) of CRC before PSM. However, T2DM did not affect the overall survival (OS) or disease-free survival (DFS) on different stages of CRC after PSM (p>0.05). Moreover, T2DM was not an independent predictor of OS or DFS (p>0.05).

Conclusion

T2DM increased overall complications after primary CRC surgery. However, T2DM might not affect OS and DFS of stage I–III CRC patients.

Considerations for clinical trial design and conduct in the evaluation of novel advanced therapeutics in neurodegenerative disease

The recent advances in the development of potentially disease modifying cell and gene therapies for neurodegenerative disease has resulted in the production of a number of promising novel therapies which are now moving forward to clinical evaluation. The robust evaluation of these therapies pose a significant number of challenges when compared to more traditional evaluations of pharmacotherapy, which is the current mainstay of neurodegenerative disease symptom management. Indeed, there is an inherent complexity in the design and conduct of these trials at multiple levels. Here we discuss specific aspects requiring consideration in the context of investigating novel cell and gene therapies for neurodegenerative disease. This extends to overarching trial designs that could be employed and the factors that underpin design choices such outcome assessments, participant selection and methods for delivery of cell and gene therapies. We explore methods of data collection that may improve efficiency in trials of cell and gene therapy to maximize data sharing and collaboration. Lastly, we explore some of the additional context beyond efficacy evaluations that should be considered to ensure implementation across relevant healthcare settings.

Laparoscopic gastrectomy for gastric cancer: has the time come for considered it a standard procedure?

Radical gastrectomy with an adequate lymphadenectomy is the main procedure which makes it possible to cure patients with resectable gastric cancer. A number of randomized controlled trials and meta-analysis provide phase III evidence that laparoscopic gastrectomy is technically safe and that it yields better short-term outcomes than conventional open gastrectomy for early-stage gastric cancer. At present, laparoscopic gastrectomy is considered a standard procedure for early-stage gastric cancer, especially in Asian countries. On the other hand, the use of minimally invasive techniques is still controversial for the treatment of more advanced tumours, principally due to existing concerns about its oncological adequacy and capacity to carry out an adequately extended lymphadenectomy. Additional high-quality studies comparing laparoscopic gastrectomy versus open gastrectomy for gastric cancer have been recently published, in particular concerning the latest results obtained by laparoscopic approach to advanced gastric cancer. It seems very useful to update the review of literature in light of these new evidences for this subject and draw some considerations.

Perioperative chemotherapy versus surgery alone for resectable colorectal liver metastases: an international multicentre propensity score matched analysis on long-term outcomes according to established prognostic risk scores

BACKGROUND

There is still uncertainty regarding the role of perioperative chemotherapy (CTx) in patients with resectable colorectal liver metastases (CRLM), especially in those with a low-risk of recurrence.

METHODS

Multicentre retrospective analysis of patients with CRLM undergoing liver resection between 2010-2015. Patients were divided into two groups according to whether they received perioperative CTx or not and were compared using propensity score matching (PSM) analysis. Then, they were stratified according to prognostic risk scores, including: Clinical Risk Score (CRS), Tumour Burden Score (TBS) and Genetic And Morphological Evaluation (GAME) score.

RESULTS

The study included 967 patients with a median follow-up of 68 months. After PSM analysis, patients with perioperative CTx presented prolonged overall survival (OS) in comparison with the surgery alone group (82.8 vs 52.5 months, p = 0.017). On multivariable analysis perioperative CTx was an independent predictor of increased OS (HR 0.705, 95%CI 0.705-0.516, p = 0.029). The benefits of perioperative CTx on survival were confirmed in patients with CRS and TBS scores ≤2 (p = 0.022 and p = 0.020, respectively) and in patients with a GAME score ≤1 (p = 0.006).

CONCLUSION

Perioperative CTx demonstrated an increase in OS in patients with CRLM. Patients with a low-risk of recurrence seem to benefit from systemic treatment.

The outcome of young vs. old gastric cancer patients following gastrectomy: a propensity score matching analysis

Purpose

The purpose of the current study was to compare the postoperative complications, overall survival and disease-free survival in young and old gastric cancer patients after gastrectomy using propensity score matching (PSM).

Methods

Adult patients (aged ≥ 18 years) who underwent gastrectomy for gastric cancer in a single clinical center from January 2013 to December 2017 were enrolled continuously for retrospective analysis. To minimize the selection bias between the young and old groups, the PSM was conducted in this study.

Results

A total of 558 patients were included in this study, with 51 patients in the young group (aged ≤ 45 years) and 507 patients in the old group (aged > 45 years). After 1:1 matching according to PSM, 51 patients in the young group were matched to 51 patients in the old group. After PSM, there was no difference in the baseline information. In terms of short-term outcomes, no difference was found in operation time (P = 0.190), intraoperative blood loss (P = 0.336), retrieved lymph nodes (P = 0.948), blood transfusion (P = 0.339), postoperative hospital stay (P = 0.194), or postoperative complications (P = 0.477) between the two groups. For overall survival, no statistically significant difference was found in all stages (P = 0.383), stage I (P = 0.431), stage II (P = 0.875) or stage III (P = 0.446) gastric cancer. Furthermore, regarding disease-free survival, no differences were found between the two groups in all stages (P = 0.378), stage I (P = 0.431), stage II (P = 0.879) or stage III (P = 0.510) gastric cancer.

Conclusion

Age might not be an independent prognostic factor for short-term outcomes, OS, or DFS in gastric cancer patients who underwent gastrectomy. The pTNM stage of GC might be an independent prognostic factor for OS and DFS.

Real-world Cardiovascular Outcomes Associated With Degarelix vs Leuprolide for Prostate Cancer Treatment

IMPORTANCE

With a growing interest in the use of real-world evidence for regulatory decision-making, it is important to understand whether real-world data can be used to emulate the results of randomized clinical trials.

OBJECTIVE

To use electronic health record and administrative claims data to emulate the ongoing PRONOUNCE trial (A Trial Comparing Cardiovascular Safety of Degarelix Versus Leuprolide in Patients With Advanced Prostate Cancer and Cardiovascular Disease).

DESIGN, SETTING, AND PARTICIPANTS

This retrospective, propensity-matched cohort study included adult men with a diagnosis of prostate cancer and cardiovascular disease who initiated either degarelix or leuprolide between December 24, 2008, and June 30, 2019. Participants were commercially insured individuals and Medicare Advantage beneficiaries included in a large US administrative claims database.

EXPOSURES

Degarelix or leuprolide.

MAIN OUTCOMES AND MEASURES

The primary end point was time to first occurrence of a major adverse cardiovascular event (MACE), defined as death due to any cause, myocardial infarction, or stroke, analogous to the PRONOUNCE trial. Secondary end points were time to death due to any cause, myocardial infarction, stroke, and angina. Cox proportional hazards regression was used to evaluate primary and secondary end points.

RESULTS

A total of 32 172 men initiated degarelix or leuprolide for prostate cancer; of them, 9490 (29.5%) had cardiovascular disease, and 7800 (24.2%) met the PRONOUNCE trial eligibility criteria and were included in this study. Overall, 165 participants (2.1%) were Asian, 1390 (17.8%) were Black, 663 (8.5%) were Hispanic, and 5258 (67.4%) were White. The mean (SD) age was 74.4 (7.4) years. Among 2226 propensity score-matched patients, no significant difference was observed in the risk of MACE for patients taking degarelix vs those taking leuprolide (10.18 vs 8.60 events per 100 person-years; hazard ratio [HR], 1.18; 95% CI, 0.86-1.61). Degarelix was associated with a higher risk of death from any cause (HR, 1.48; 95% CI, 1.01-2.18) but not of myocardial infarction (HR, 1.16; 95% CI, 0.60-2.25), stroke (HR, 0.92; 95% CI, 0.45-1.85), or angina (HR, 1.36; 95% CI, 0.43-4.27).

CONCLUSIONS AND RELEVANCE

In this emulation of a clinical trial of men with cardiovascular disease undergoing treatment for prostate cancer, degarelix was not associated with a lower risk of cardiovascular events than leuprolide. Comparison of these data with PRONOUNCE trial results, when published, will help enhance our understanding of the appropriate role of using real-world data to emulate clinical trials.

Silicone oil versus gas tamponade for primary rhegmatogenous retinal detachment treated successfully with a propensity score analysis: Japan Retinal Detachment Registry

Background/aims

To compare the effects of silicone oil tamponade (SOT) to that of gas tamponade (GT) on the best-corrected visual acuity (BCVA) after successful vitrectomy for retinal detachment (RD).

Methods

A retrospective, multicentre, nationwide study with RD who were registered in the Japan-RD Registry. All cases with RD treated with successful vitrectomy between February 2016 and March 2017 were studied. A propensity score matching was performed using the preoperative findings as covariates to adjust the relevant confounders. The primary outcome was the estimated mean difference of the postoperative BCVA in 6 months between eyes treated with SOT to those treated with GT.

Results

Of the 3446 cases registered, 2097 cases met the entry criteria. There were 2042 eyes that had GT and 55 eyes that had SOT. Primary success was defined as a reattached retina with no tamponade at 6 months. After propensity score matching, each group contained 40 cases. The preoperative BCVA was 0.966±0.738 logMAR units in the GT group and 1.270±0.945 logMAR units in the SOT group (p=0.177). Six months postoperatively, the BCVA in the GT group was significantly better at 0.309 logMAR units in the GT group than the 0.671 logMAR units in the SOT group (p=0.002).

Conclusions

Even after successful surgery for RD, eyes that experienced SOT had poorer BCVA than eyes treated with GOT. SOT should be considered cautiously.

Precis

Propensity score analysis of eyes with rhegmatogenous RD showed that postoperative vision was worse in eyes treated once with silicone oil than with gas even after completely successful surgery.

Pure laparoscopic versus robotic liver resections: Multicentric propensity score-based analysis with stratification according to difficulty scores

BACKGROUND

The benefits of pure laparoscopic and robot-assisted liver resections (LLR and RALR) are known in comparison to open surgery. The aim of the present retrospective comparative study is to investigate the role of RALR and LLR according to different levels of difficulty.

METHODS

The institutional databases of six high-volume hepatobiliary centers were retrospectively reviewed. The study population was divided in two groups: LLR and RALR. The procedures were stratified for difficulty levels accordingly to three classifications. A propensity score matching was implemented to mitigate selection bias. Short-term outcomes were the object of comparison.

RESULTS

Nine hundred and thirty-six LLR and 403 RALR were collected. RALR exhibited fewer cases of intraoperative blood loss, lower transfusion and conversion rates (especially for oncological radicality) than LLR in the setting of highly difficult operations, whereas LLR had lower postoperative morbidity and fewer low-grade complications. For intermediate and low-difficulty resections, the intraoperative advantages of RALR gradually decreased to nonsignificant results and LLR remained associated with lower postoperative morbidity.

CONCLUSION

Robot-assisted liver resections do not show operative nor clinically significant benefits over LLR for low- and intermediate-difficulty resections. By reducing conversion rates, RALR can favour the operative feasibility of difficult resections possibly extending the indications of minimally invasive approaches for liver resection.