Treatments effects from randomized trials and propensity score analyses were similar in similar populations in an example from cardiac surgery

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.

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.

Spousal bereavement and its effects on later life physical and cognitive capability: the Tromsø study

Spousal bereavement is associated with health declines and increased mortality risk, but its specific impact on physical and cognitive capabilities is less studied. A historical cohort study design was applied including married Tromsø study participants (N=5739) aged 50-70 years with baseline self-reported overall health and health-related factors and measured capability (grip strength, finger tapping, digit symbol coding, and short-term recall) at follow-up. Participants had data from Tromsø4 (1994-1995) and Tromsø5 (2001), or Tromsø6 (2007-2008) and Tromsø7 (2015-2016). Propensity score matching, adjusted for baseline confounders (and baseline capability in a subset), was used to investigate whether spousal bereavement was associated with poorer subsequent capability. Spousal bereavement occurred for 6.2% on average 3.7 years (SD 2.0) before the capability assessment. There were no significant bereavement effects on subsequent grip strength, immediate recall, or finger-tapping speed. Without adjustment for baseline digit symbol coding test performance, there was a negative significant effect on the digit symbol coding test (ATT -1.33; 95% confidence interval -2.57, -0.10), but when baseline digit symbol coding test performance was taken into account in a smaller subsample, using the same set of matching confounders, there was no longer any association (in the subsample ATT changed from -1.29 (95% CI -3.38, 0.80) to -0.04 (95% CI -1.83, 1.75). The results in our study suggest that spousal bereavement does not have long-term effects on the intrinsic capacity components physical or cognition capability to a notable degree.

Can propensity score matching replace randomized controlled trials?

Randomized controlled trials (RCTs) have long been recognized as the gold standard for establishing causal relationships in clinical research. Despite that, various limitations of RCTs prevent its widespread implementation, ranging from the ethicality of withholding potentially-lifesaving treatment from a group to relatively poor external validity due to stringent inclusion criteria, amongst others. However, with the introduction of propensity score matching (PSM) as a retrospective statistical tool, new frontiers in establishing causation in clinical research were opened up. PSM predicts treatment effects using observational data from existing sources such as registries or electronic health records, to create a matched sample of participants who received or did not receive the intervention based on their propensity scores, which takes into account characteristics such as age, gender and comorbidities. Given its retrospective nature and its use of observational data from existing sources, PSM circumvents the aforementioned ethical issues faced by RCTs. Majority of RCTs exclude elderly, pregnant women and young children; thus, evidence of therapy efficacy is rarely proven by robust clinical research for this population. On the other hand, by matching study patient characteristics to that of the population of interest, including the elderly, pregnant women and young children, PSM allows for generalization of results to the wider population and hence greatly increases the external validity. Instead of replacing RCTs with PSM, the synergistic integration of PSM into RCTs stands to provide better research outcomes with both methods complementing each other. For example, in an RCT investigating the impact of mannitol on outcomes among participants of the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial, the baseline characteristics of comorbidities and current medications between treatment and control arms were significantly different despite the randomization protocol. Therefore, PSM was incorporated in its analysis to create samples from the treatment and control arms that were matched in terms of these baseline characteristics, thus providing a fairer comparison for the impact of mannitol. This literature review reports the applications, advantages, and considerations of using PSM with RCTs, illustrating its utility in refining randomization, improving external validity, and accounting for non-compliance to protocol. Future research should consider integrating the use of PSM in RCTs to better generalize outcomes to target populations for clinical practice and thereby benefit a wider range of patients, while maintaining the robustness of randomization offered by RCTs.

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.

Impact of neoadjuvant chemotherapy on the difficulty and outcomes of laparoscopic and robotic major liver resections for colorectal liver metastases: A propensity-score and coarsened exact-matched controlled study

BACKGROUND

Minimal invasive liver resections are a safe alternative to open surgery. Different scoring systems considering different risks factors have been developed to predict the risks associated with these procedures, especially challenging major liver resections (MLR). However, the impact of neoadjuvant chemotherapy (NAT) on the difficulty of minimally invasive MLRs remains poorly investigated.

METHODS

Patients who underwent laparoscopic and robotic MLRs for colorectal liver metastases (CRLM) performed across 57 centers between January 2005 to December 2021 were included in this analysis. Patients who did or did not receive NAT were matched based on 1:1 coarsened exact and 1:2 propensity-score matching. Pre- and post-matching comparisons were performed.

RESULTS

In total, the data of 5189 patients were reviewed. Of these, 1411 procedures were performed for CRLM, and 1061 cases met the inclusion criteria. After excluding 27 cases with missing data on NAT, 1034 patients (NAT: n = 641; non-NAT: n = 393) were included. Before matching, baseline characteristics were vastly different. Before matching, the morbidity rate was significantly higher in the NAT-group (33.2% vs. 27.2%, p-value = 0.043). No significant differences were seen in perioperative outcomes after the coarsened exact matching. After the propensity-score matching, statistically significant higher blood loss (mean, 300 (SD 128-596) vs. 250 (SD 100-400) ml, p-value = 0.047) but shorter hospital stay (mean, 6 [4-8] vs. 6 [5-9] days, p-value = 0.043) were found in the NAT-group.

CONCLUSION

The current study demonstrated that NAT had minimal impact on the difficulty and outcomes of minimally-invasive MLR for CRLM.

Radical cystectomy versus trimodality therapy for muscle-invasive bladder cancer: a multi-institutional propensity score matched and weighted analysis

BACKGROUND

Previous randomised controlled trials comparing bladder preservation with radical cystectomy for muscle-invasive bladder cancer closed due to insufficient accrual. Given that no further trials are foreseen, we aimed to use propensity scores to compare trimodality therapy (maximal transurethral resection of bladder tumour followed by concurrent chemoradiation) with radical cystectomy.

METHODS

This retrospective analysis included 722 patients with clinical stage T2-T4N0M0 muscle-invasive urothelial carcinoma of the bladder (440 underwent radical cystectomy, 282 received trimodality therapy) who would have been eligible for both approaches, treated at three university centres in the USA and Canada between Jan 1, 2005, and Dec 31, 2017. All patients had solitary tumours less than 7 cm, no or unilateral hydronephrosis, and no extensive or multifocal carcinoma in situ. The 440 cases of radical cystectomy represent 29% of all radical cystectomies performed during the study period at the contributing institutions. The primary endpoint was metastasis-free survival. Secondary endpoints included overall survival, cancer-specific survival, and disease-free survival. Differences in survival outcomes by treatment were analysed using propensity scores incorporated in propensity score matching (PSM) using logistic regression and 3:1 matching with replacement and inverse probability treatment weighting (IPTW).

FINDINGS

In the PSM analysis, the 3:1 matched cohort comprised 1119 patients (837 radical cystectomy, 282 trimodality therapy). After matching, age (71·4 years [IQR 66·0-77·1] for radical cystectomy vs 71·6 years [64·0-78·9] for trimodality therapy), sex (213 [25%] vs 68 [24%] female; 624 [75%] vs 214 [76%] male), cT2 stage (755 [90%] vs 255 [90%]), presence of hydronephrosis (97 [12%] vs 27 [10%]), and receipt of neoadjuvant or adjuvant chemotherapy (492 [59%] vs 159 [56%]) were similar between groups. Median follow-up was 4·38 years (IQR 1·6-6·7) versus 4·88 years (2·8-7·7), respectively. 5-year metastasis-free survival was 74% (95% CI 70-78) for radical cystectomy and 75% (70-80) for trimodality therapy with IPTW and 74% (70-77) and 74% (68-79) with PSM. There was no difference in metastasis-free survival either with IPTW (subdistribution hazard ratio [SHR] 0·89 [95% CI 0·67-1·20]; p=0·40) or PSM (SHR 0·93 [0·71-1·24]; p=0·64). 5-year cancer-specific survival for radical cystectomy versus trimodality therapy was 81% (95% CI 77-85) versus 84% (79-89) with IPTW and 83% (80-86) versus 85% (80-89) with PSM. 5-year disease-free survival was 73% (95% CI 69-77) versus 74% (69-79) with IPTW and 76% (72-80) versus 76% (71-81) with PSM. There were no differences in cancer-specific survival (IPTW: SHR 0·72 [95% CI 0·50-1·04]; p=0·071; PSM: SHR 0·73 [0·52-1·02]; p=0·057) and disease-free survival (IPTW: SHR 0·87 [0·65-1·16]; p=0·35; PSM: SHR 0·88 [0·67-1·16]; p=0·37) between radical cystectomy and trimodality therapy. Overall survival favoured trimodality therapy (IPTW: 66% [95% CI 61-71] vs 73% [68-78]; hazard ratio [HR] 0·70 [95% CI 0·53-0·92]; p=0·010; PSM: 72% [69-75] vs 77% [72-81]; HR 0·75 [0·58-0·97]; p=0·0078). Outcomes for radical cystectomy and trimodality therapy were not statistically different among centres for cancer-specific survival and metastasis-free survival (p=0·22-0·90). Salvage cystectomy was done in 38 (13%) trimodality therapy patients. Pathological stage in the 440 radical cystectomy patients was pT2 in 124 (28%), pT3-4 in 194 (44%), and 114 (26%) node positive. The median number of nodes removed was 39, the soft tissue positive margin rate was 1% (n=5), and the perioperative mortality rate was 2·5% (n=11).

INTERPRETATION

This multi-institutional study provides the best evidence to date showing similar oncological outcomes between radical cystectomy and trimodality therapy for select patients with muscle-invasive bladder cancer. These results support that trimodality therapy, in the setting of multidisciplinary shared decision making, should be offered to all suitable candidates with muscle-invasive bladder cancer and not only to patients with significant comorbidities for whom surgery is not an option.

FUNDING

Sinai Health Foundation, Princess Margaret Cancer Foundation, Massachusetts General Hospital.

Serum Ferritin Has Limited Prognostic Value on Mortality Risk in Patients with Decompensated Cirrhosis: A Propensity Score Matching Analysis

OBJECTIVE

The prognostic value of serum ferritin remains elusive in the literature. We aimed to examine the association between serum ferritin and mortality risk in cirrhosis.

METHODS

A total of 257 cirrhotic patients were recruited. The cut-off of serum ferritin was determined by X-tile. The Cox regression and Kaplan-Meier method were used. A 1:1 propensity score matching (PSM) was performed to diminish the impacts of selection bias and possible confounders.

RESULTS

The difference regarding mortality was mostly significant for serum ferritin >158 ng/mL. Before PSM, serum ferritin >158 ng/mL was an independent predictor of mortality. However, the clinical relevance of high ferritin level for prognostication was blunted after PSM (survival rate: 86.8% vs 96.3%, P = .078). Cox regression indicated that model for end-stage liver disease remains only independent risk factor of 180-day mortality after PSM.

CONCLUSION

Serum ferritin may not serve as an independent prognostic indicator of mortality risk in decompensated cirrhotic patients.

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.

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.

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.

Hospitalisation following therapeutic community drug and alcohol treatment for young people with and without a history of criminal conviction

INTRODUCTION

This study examines the association between treatment in a therapeutic community for adolescents with drug and alcohol problems on hospitalisation outcomes up to 15 years later for all clients, and separately for those with and without a history of criminal conviction.

METHOD

A quasi-experimental design was used to examine the linked administrative health and criminal justice records for all adolescents admitted to the Program for Adolescent Life Management (PALM) from January 2001 to December 2016 (n = 3059) in Sydney, Australia. ICD-10AM codes were used to designate hospitalisation outcomes as either physical injury, mental health problems, substance use disorders, or organic illness. The treatment and comparison groups were matched on factors associated with program retention, resulting in a final sample of 1266 clients. We examined the rate of hospitalisation up to 15 years posttreatment for all clients and stratified by prior conviction status using Cox regression analyses.

RESULTS

The treatment group had significantly lower rates of hospitalisation for a physical injury (HR = 0.77 [95% CI = 0.61-0.98]), mental health problem (HR = 0.62 [95% CI = 0.47-0.81]), substance use disorder (HR = 0.59 [95% CI = 0.47-0.75]), and organic illness (HR = 0.71 [95% CI = 0.55-0.92]). There was a significant interaction between treatment and prior criminal conviction status on rate of hospitalisation for physical injury, suggesting that the effect of treatment on physical injury was significantly greater for clients with a prior criminal conviction.

CONCLUSIONS

Adolescents who engage in a therapeutic community treatment program may have a long-lasting reduction in the risk of subsequent hospitalisation. This also appears to apply to those with a history of criminal conviction.

Corticosteroids and Other Treatments Administered to Children Tested for SARS-CoV-2 Infection in Emergency Departments

OBJECTIVE

We sought to determine if corticosteroid administration is associated with a SARS-CoV-2 nucleic acid test-positive result and to describe therapies administered to SARS-CoV-2 infected children.

METHODS

We collected cross-sectional data from participants recruited in 41 pediatric emergency departments (ED) in 10 countries between March 2020 and June 2021. Participants were <18 years old, had signs or symptoms of, or risk factors for acute SARS-CoV-2 infection, and had nucleic acid testing performed. To determine if SARS-CoV-2 test status was independently associated with corticosteroid administration, we used a multivariable conditional logistic regression model matched by study site to compare treatments administered based on SARS-CoV-2 test and disposition status. This analysis was repeated for the subgroup of study participants who were hospitalized.

RESULTS

30.3% (3,121/10,315) of participants were SARS-CoV-2-positive. Although remdesivir was more commonly administered to SARS-CoV-2-positive children, use was infrequent (25/3120 [0.8%] vs 1/7188 [0.01%]; P = .001). Corticosteroid use was less common among SARS-CoV-2-positive children (219/3120 [7.0%] vs 759/7190 [10.6%]; P < .001). Among hospitalized children, there were no differences in provision of inotropes, respiratory support, chest drainage or extracorporeal membrane oxygenation between groups. Corticosteroid administration was associated with age, history of asthma, wheezing, study month, hospitalization and intensive care unit admission; it was not associated with a positive SARS-CoV-2 test result overall (aOR: 0.91; 95%CI: 0.74, 1.12) or among the subgroup of those hospitalized (aOR: 1.04; 95%CI: 0.75, 1.44).

CONCLUSIONS

Few disease-specific treatments are provided to SARS-CoV-2-positive children; clinical trials evaluating therapies in children are urgently needed.

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.

Injury Characteristics and Predisposing Effects of Various Outdoor Traumatic Situations in Children and Adolescents

Backgroud

Many studies have reported injury characteristics of individual traumatic situations. However, a comparative analysis of specific risks is meaningful to better understand injury characteristics and help establish injury-prevention measures. This study was conducted to investigate and compare injury characteristics in children and adolescents by various outdoor traumatic situations.

Methods

Outdoor traumatic situations were determined and classified into physical activity-related injury (n = 3,983) and pedestrian (n = 784) and passenger (n = 1,757) injuries in traffic accidents. Home injury (n = 16,121) was used as the control group. Then, the characteristics of each outdoor trauma were compared with 1:1 matched indoor trauma (among home injuries); each outdoor traumatic situation's predisposing risk for the injured body part, injury type, and injury severity were analyzed; and changes by age of frequency ranking among physical activity-related injuries were investigated.

Results

Outdoor trauma showed higher risks for limb injuries (injured body part), fracture and muscle/tendon injuries (injury type), and severe injuries (severity) than indoor trauma. Various outdoor traumatic situations presented different predisposing effects on injury characteristics. Among physical activity-related injuries, bicycle injury was commonest across all ages, and playing activities were common causes for injury for individuals of age < 9 years, whereas sports activities overwhelmed the common causes thereafter.

Conclusions

The findings would help to better understand the specific injury risk of various outdoor traumatic situations and may potentially facilitate the establishment of more effective injury-prevention measures.

Rectally Administered Low-Dose Diclofenac Has No Effect on Preventing Post-Endoscopic Retrograde Cholangiopancreatography Pancreatitis: A Propensity Score Analysis

OBJECTIVES

We evaluated the preventive effect of low-dose diclofenac (25-50 mg) on post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) by propensity score matching analysis.

METHODS

We retrospectively analyzed the data of 515 patients who underwent ERCP for the first time with or without the rectal administration of low-dose diclofenac before the procedure. For the purpose of minimization of the intrinsic selection bias, we compared the incidence rate of PEP between the diclofenac and control group after propensity score matching.

RESULTS

Post-ERCP pancreatitis developed in 15 patients (2.9%). There was no significant difference in the incidence of PEP between the diclofenac (2.4%) and control group (3.3%) (P = 0.608). One hundred ninety matched pairs were generated by propensity score matching and analyzed; however, the incidence rate of PEP was the same in both groups (2.1%, P = 1.000). In the subgroup analysis using data of patients with high-risk factors for developing PEP, the incidence rate of PEP was comparable between the diclofenac (3.8%) and control groups (4.0%) (P = 0.917).

CONCLUSIONS

In our propensity score analysis, rectal administration of low-dose diclofenac was not shown to be useful in preventing PEP.

A comprehensive multidisciplinary care pathway for hip fractures better outcome than usual care?

INTRODUCTION

Hip fracture surgery is among the most performed surgical procedures in elderly patients. Mortality rates are high, however, and patients often fail to live independently following a hip fracture. To improve outcome, multidisciplinary care pathways have been initiated, but longer-term results are lacking. Aim of this study was to compare functional outcome and living situation six months after hip fracture treatment with and without a care pathway.

PATIENTS AND METHODS

A multicentre prospective controlled trial was conducted with three hospitals: in one hospital patients were treated with a care pathway, in the other hospitals patients received usual care. All patients aged ≥ 60 years with a hip fracture were asked to participate. Besides basic characteristics, health-related quality of life (EQ-5D) and performance scores of activities of daily living (Katz Index and Lawton IADL) were assessed. Differences in scores were analysed using linear regression. Propensity score adjustment was used to correct for differences between the care pathway and the usual care group. Missing data were imputed.

RESULTS

No differences in rate of return to prefracture ADL level were found between patients in the care pathway group and the usual care group. The percentage of participants in the same situation as before the fracture was the same in both treatment groups (81%). There were no significant differences in quality of life, activities of daily living or mortality (15% vs 10%, p = 0.17), but hospital stay in the care pathway group was significantly shorter (median 7 vs 10 days).

DISCUSSION

Treatment of elderly patients with a hip fracture is commonly organised in care pathways. Although short-term advantages are reported, positive effects on longer-term functional results could not be proven in our study. This study confirmed a shorter hospital stay in the care pathway group, which potentially may lead to a reduction in costs.

CONCLUSIONS

Functional outcome and living situation six months after a hip fracture is the same for patients treated with or without a care pathway.

Comparison between short and long-term outcomes after minimally invasive versus open primary liver resections for hepatocellular carcinoma: A 1:1 matched analysis

BACKGROUND

This study aims to compare the short- and long-term outcomes of patients undergoing minimally invasive liver resection (MILR) versus open liver resection (OLR) for nonrecurrent hepatocellular carcinoma (HCC).

METHODS

Review of 204 MILR and 755 OLR without previous LR performed between 2005 and 2018. 1:1 coarsened exact matching (CEM) and 1:1 propensity-score matching (PSM) were performed.

RESULTS

Overall, 190 MILR were well-matched with 190 OLR by PSM and 86 MILR with 86 OLR by CEM according to patient baseline characteristics. After PSM and CEM, MILR was associated with a significantly longer operation time [230 min (interquartile range [IQR], 145-330) vs. 160 min (IQR, 125-210), p < .001] [215 min (IQR, 135-295) vs. 153.5 min (120-180), p < .001], shorter postoperative stay [4 days (IQR, 3-6) vs. 6 days (IQR, 5-8), p = .001)] [4 days (IQR, 3-5) vs. 6 days (IQR, 5-7), p = .004] and lower postoperative morbidity [40 (21%) vs. 67 (35.5%), p = .003] [16 (18.6%) vs. 27 (31.4%), p = .036] compared to OLR. MILR was also associated with a significantly longer median time to recurrence (70 vs. 40.3 months, p = .014) compared to OLR after PSM but not CEM. There was no significant difference in terms of overall survival and recurrence-free survival.

CONCLUSION

MILR is associated with superior short-term postoperative outcomes and with at least equivalent long-term oncological outcomes compared to OLR for HCC.

Comparing Propensity Score Methods Versus Traditional Regression Analysis for the Evaluation of Observational Data: A Case Study Evaluating the Treatment of Gram-Negative Bloodstream Infections

BACKGROUND

Propensity score methods are increasingly being used in the infectious diseases literature to estimate causal effects from observational data. However, there remains a general gap in understanding among clinicians on how to critically review observational studies that have incorporated these analytic techniques.

METHODS

Using a cohort of 4967 unique patients with Enterobacterales bloodstream infections, we sought to answer the question "Does transitioning patients with gram-negative bloodstream infections from intravenous to oral therapy impact 30-day mortality?" We conducted separate analyses using traditional multivariable logistic regression, propensity score matching, propensity score inverse probability of treatment weighting, and propensity score stratification using this clinical question as a case study to guide the reader through (1) the pros and cons of each approach, (2) the general steps of each approach, and (3) the interpretation of the results of each approach.

RESULTS

2161 patients met eligibility criteria with 876 (41%) transitioned to oral therapy while 1285 (59%) remained on intravenous therapy. After repeating the analysis using the 4 aforementioned methods, we found that the odds ratios were broadly similar, ranging from 0.84-0.95. However, there were some relevant differences between the interpretations of the findings of each approach.

CONCLUSIONS

Propensity score analysis is overall a more favorable approach than traditional regression analysis when estimating causal effects using observational data. However, as with all analytic methods using observational data, residual confounding will remain; only variables that are measured can be accounted for. Moreover, propensity score analysis does not compensate for poor study design or questionable data accuracy.

Risk of preterm birth and neonatal outcomes after cerclage placement in triplet pregnancies

BACKGROUND

The number of triplet pregnancies in the United States has increased significantly. Perinatal morbidity and mortality are higher in these pregnancies mainly due to higher preterm birth rates. Interventions to decrease the risk of preterm delivery in this population are needed. Evidence regarding cerclage placement in triplets is limited. We performed a population-based, retrospective cohort study to study the risk of preterm birth and neonatal outcomes after cerclage placement in triplet pregnancies.

METHODS

All U.S. triplet deliveries from 2006 to 2013 with risk factors for cervical insufficiency were selected, excluding cases with indicated preterm delivery. Cases were categorized according to cerclage placement status. The risk of preterm birth and adverse neonatal outcomes were calculated using propensity score analysis, generalized linear, and logistic regression models.

RESULTS

From ∼33 million deliveries, 43,000 were triplets, and 7308 fulfilled eligibility criteria. There was no difference in the gestational age at delivery between the cerclage and noncerclage groups, aOR (95% CI) = 1.0(0.9-1.0). The difference between the risk of preterm delivery at <34 weeks and <32 weeks was not statistically significant. The risk of the composite outcome of neonatal complications was higher in the cerclage compared to the noncerclage group, aOR (95% CI) = 1.5 (1.1-2.2).

CONCLUSIONS

Cerclage placement in triplet pregnancies does not appear to decrease preterm birth rates and seems to increase the risk of neonatal complications.

Systematic differences in effect estimates between observational studies and randomized control trials in meta-analyses in nephrology

The limited availability of randomized controlled trials (RCTs) in nephrology undermines causal inferences in meta-analyses. Systematic reviews of observational studies have grown more common under such circumstances. We conducted systematic reviews of all comparative observational studies in nephrology from 2006 to 2016 to assess the trends in the past decade. We then focused on the meta-analyses combining observational studies and RCTs to evaluate the systematic differences in effect estimates between study designs using two statistical methods: by estimating the ratio of odds ratios (ROR) of the pooled OR obtained from observational studies versus those from RCTs and by examining the discrepancies in their statistical significance. The number of systematic reviews of observational studies in nephrology had grown by 11.7-fold in the past decade. Among 56 records combining observational studies and RCTs, ROR suggested that the estimates between study designs agreed well (ROR 1.05, 95% confidence interval 0.90-1.23). However, almost half of the reviews led to discrepant interpretations in terms of statistical significance. In conclusion, the findings based on ROR might encourage researchers to justify the inclusion of observational studies in meta-analyses. However, caution is needed, as the interpretations based on statistical significance were less concordant than those based on ROR.

Difference in surgical outcomes of rectal cancer by study design: meta-analyses of randomized clinical trials, case-matched studies, and cohort studies

Background

RCTs are considered the standard in surgical research, whereas case-matched studies and propensity score matching studies are conducted as an alternative option. Both study designs have been used to investigate the potential superiority of robotic surgery over laparoscopic surgery for rectal cancer. However, no conclusion has been reached regarding whether there are differences in findings according to study design. This study aimed to examine similarities and differences in findings relating to robotic surgery for rectal cancer by study design.

Methods

A comprehensive literature search was conducted using PubMed, Scopus, and Cochrane CENTRAL to identify RCTs, case-matched studies, and cohort studies that compared robotic versus laparoscopic surgery for rectal cancer. Primary outcomes were incidence of postoperative overall complications, incidence of anastomotic leakage, and postoperative mortality. Meta-analyses were performed for each study design using a random-effects model.

Results

Fifty-nine articles were identified and reviewed. No differences were observed in incidence of anastomotic leakage, mortality, rate of positive circumferential resection margins, conversion rate, and duration of operation by study design. With respect to the incidence of postoperative overall complications and duration of hospital stay, the superiority of robotic surgery was most evident in cohort studies (risk ratio (RR) 0.83, 95 per cent c.i. 0.74 to 0.92, P < 0.001; mean difference (MD) –1.11 (95 per cent c.i. –1.86 to –0.36) days, P = 0.004; respectively), and least evident in RCTs (RR 1.12, 0.91 to 1.38, P = 0.27; MD –0.28 (–1.44 to 0.88) days, P = 0.64; respectively).

Conclusion

Results of case-matched studies were often similar to those of RCTs in terms of outcomes of robotic surgery for rectal cancer. However, case-matched studies occasionally overestimated the effects of interventions compared with RCTs.

Similarities and differences between study designs in short- and long-term outcomes of laparoscopic versus open low anterior resection for rectal cancer: A systematic review and meta-analysis of randomized, case-matched, and cohort studies

AIM

Randomized controlled trials (RCT) are the gold standard in surgical research, and case-matched studies, such as studies with propensity score matching, are expected to serve as an alternative to RCT. Both study designs have been used to investigate the potential superiority of laparoscopic surgery to open surgery for rectal cancer, but it remains unclear whether there are any differences in the findings obtained using these study designs. We aimed to examine similarities and differences between findings from different study designs regarding laparoscopic surgery for rectal cancer.

METHODS

Systematic review and meta-analyses. A comprehensive literature search was conducted using PubMed, Scopus, and Cochrane. RCT, case-matched studies, and cohort studies comparing laparoscopic low anterior resection and open low anterior resection for rectal cancer were included. In total, 8 short-term outcomes and 3 long-term outcomes were assessed. Meta-analysis was conducted stratified by study design using a random-effects model.

RESULTS

Thirty-five studies were included in this review. Findings did not differ between RCT and case-matched studies for most outcomes. However, the estimated treatment effect was largest in cohort studies, intermediate in case-matched studies, and smallest in RCT for overall postoperative complications and 3-year local recurrence.

CONCLUSION

Findings from case-matched studies were similar to those from RCT in laparoscopic low anterior resection for rectal cancer. However, findings from case-matched studies were sometimes intermediate between those of RCT and unadjusted cohort studies, and case-matched studies and cohort studies have a potential to overestimate the treatment effect compared with RCT.

Is There an Age Cutoff for Intracranial Pressure Monitoring?: A Propensity Score Matched Analysis of the National Trauma Data Bank

BACKGROUND

Despite mostly favorable past evidence for use of intracranial pressure monitoring (ICPM), more recent data question not only the indications but also the utility of ICPM. The Fourth Edition Brain Trauma Foundation guidelines offer limited indications for ICPM. Evidence supports ICPM for reducing mortality in patients with severe traumatic brain injury (TBI) and cites decreased survival in elderly patients.

METHODS

All patients ≥ 18 years of age with isolated TBI, head Abbreviated Injury Scale (AIS) ≥ 3, and a Glasgow Coma Scale (GCS) ≤ 8 between 2008 and 2014 were included from the National Trauma Data Bank. Exclusion criteria were head AIS = 6 and death within 24 hours. Patients with and without ICPM were compared using TBI-specific variables. Patients were then matched via propensity-score matching (PSM), and the odds ratio (OR) of death with ICPM was determined using logistic regression modeling for 8 different age strata.

RESULTS

A total of 23,652 patients with a mean age of 56 years, median head AIS of 4, median GCS of 3, and overall mortality of 29.2% were analyzed. After PSM, ICPM was associated with death beginning at the age stratum of 56-65 years. Intracranial pressure monitoring was associated with survival beginning at the age-group 36-45 years.

DISCUSSION

Based on a large propensity-matched sample of TBI patients, ICPM was not associated with improved survival for TBI patients above 55 years of age. Until level 1 evidence is available, this age threshold should be considered for further prospective study in determining indications for ICPM.

Compared to randomized studies, observational studies may overestimate the effectiveness of DOACs: a metaepidemiological approach

BACKGROUND AND OBJECTIVES

Randomized controlled trials (RCTs) are criticized for including patients who are overselected. Health authorities consequently encourage "real-world" postmarketing cohort studies. Our objective was to determine the differences between RCTs and observational studies as regards their populations and efficacy/safety results.

METHODS

A systematic review was conducted to identify RCTs and observational studies including patients with venous thromboembolism receiving direct oral anticoagulants or conventional treatment. Ratios of hazard ratio (RHR) comparing epidemiological studies (prospective and retrospective cohort studies and studies using living databases) with RCTs were computed.

RESULTS

Six RCTs (27,121 patients) and twenty observational studies (248,971 patients) were identified and analyzed. Prospective cohort studies seemed to recruit patients who were no less selected than those of RCTs whereas other types of observational studies may reflect the population treated in real life. Among observational studies, prospective cohort studies yielded the most favorable estimates of treatment effect compared with RCTs. These studies were associated with a nonsignificant 33% increase in efficacy estimate (RHR 0.67, [95% CI, 0.39-1.18]) but no effect on safety estimate. Studies using living databases were associated with nonsignificant trends toward a greater effect on efficacy (RHR 0.82, [0.66-1.01]) and a smaller effect on safety (RHR 1.33, [0.96-1.84]).

DISCUSSION

Overall, in this clinical setting, an exaggeration of the treatment efficacy estimate was seen with observational studies compared with RCTs.

CONCLUSIONS

As the presence of residual confounding cannot be excluded, these results should be interpreted cautiously.

Survival Advantage of Laparoscopic Versus Open Resection For Colorectal Liver Metastases: A Meta-analysis of Individual Patient Data From Randomized Trials and Propensity-score Matched Studies

OBJECTIVE

To perform an individual participant data meta-analysis using randomized trials and propensity-score matched (PSM) studies which compared laparoscopic versus open hepatectomy for patients with colorectal liver metastases (CLM).

BACKGROUND

Randomized trials and PSM studies constitute the highest level of evidence in addressing the long-term oncologic efficacy of laparoscopic versus open resection for CLM. However, individual studies are limited by the reporting of overall survival in ways not amenable to traditional methods of meta-analysis, and violation of the proportional hazards assumption.

METHODS

Survival information of individual patients was reconstructed from the published Kaplan-Meier curves with the aid of a computer vision program. Frequentist and Bayesian survival models (taking into account random-effects and nonproportional hazards) were fitted to compare overall survival of patients who underwent laparoscopic versus open surgery. To handle long plateaus in the tails of survival curves, we also exploited "cure models" to estimate the fraction of patients effectively "cured" of disease.

RESULTS

Individual patient data from 2 randomized trials and 13 PSM studies involving 3148 participants were reconstructed. Laparoscopic resection was associated with a lower hazard rate of death (stratified hazard ratio = 0.853, 95% confidence interval: 0.754-0.965, P = 0.0114), and there was evidence of time-varying effects (P = 0.0324) in which the magnitude of hazard ratios increased over time. The fractions of long-term cancer survivors were estimated to be 47.4% and 18.0% in the laparoscopy and open surgery groups, respectively. At 10-year follow-up, the restricted mean survival time was 8.6 months (or 12.1%) longer in the laparoscopy arm (P < 0.0001). In a subgroup analysis, elderly patients (≥65 years old) treated with laparoscopy experienced longer 3-year average life expectancy (+6.2%, P = 0.018), and those who live past the 5-year milestone (46.1%) seem to be cured of disease.

CONCLUSIONS

This patient-level meta-analysis of high-quality studies demonstrated an unexpected survival benefit in favor of laparoscopic over open resection for CLM in the long-term. From a conservative viewpoint, these results can be interpreted to indicate that laparoscopy is at least not inferior to the standard open approach.

Associations of Bariatric Interventions With Micronutrient and Endocrine Disturbances

IMPORTANCE

Few studies have described the longitudinal trajectories of serum levels of micronutrients whose deficiencies are associated with serious sequelae following bariatric procedures, such as anemia, osteoporotic fractures, and neuropathies. Furthermore, previous studies comparing laparoscopic sleeve gastrectomy (LSG) vs Roux-en-Y gastric bypass (LRYGB) or one-anastomosis gastric bypass (OAGB) procedures may have been limited by selection and confounding biases.

OBJECTIVE

To appraise the spectrum and temporal course of micronutrient deficiencies associated with bone metabolism and erythropoiesis after LSG vs OAGB or LRYGB procedures, using the propensity score as a balancing score.

DESIGN, SETTING, AND PARTICIPANTS

This prospective, longitudinal comparative effectiveness study was conducted at a high-volume bariatric unit in Singapore from September 1, 2008, to November 30, 2017, with a cutoff date for analysis of September 2018. Patients who underwent adjustable gastric banding, biliopancreatic diversion procedures, and intragastric balloon procedures were excluded. All other patients who underwent bariatric procedures were included. Data were analyzed from September 23 to 30, 2018.

MAIN OUTCOMES AND MEASURES

Serial assessment of 13 biochemical parameters at 12 time points for up to 5 years after bariatric procedure. Inverse probability-of-treatment weights were used to obtain estimates of the mean associations of variables assessed with the bariatric surgical interventions. Longitudinal trajectories were analyzed using mixed-effects generalized linear models to apportion the temporal variation of serum micronutrients into fixed-effects and random-effects components.

RESULTS

A total of 688 patients were included in this study, of whom 499 underwent LSG (mean [SD] age, 41.5 [11.3] years; 318 [63.7%] women) and 189 underwent OAGB or LRYGB (mean [SD] age, 48.6 [9.4] years; 112 [59.3%] women). There were no differences during follow-up among patients who underwent LSG vs those who underwent OAGB or LRYGB in intact parathyroid hormone levels (mean difference, 7.05 [95% CI, -28.67 to 42.77] pg/mL; P = .70), serum 25-hydroxyvitamin D levels (mean difference, -0.72 [95% CI, -1.56 to 0.12] ng/mL; P = .09), or phosphate levels (mean difference, 0.006 [95% CI, -0.052 to 0.064] mg/dL; P = .83). Hemoglobin levels were a mean 0.63 (95% CI, 0.41 to 0.85) g/dL higher among patients who underwent LSG compared with those who underwent OAGB or LRYGB (P < .001), despite no differences in iron concentration levels (mean difference, 1.50 [95% CI, -1.39 to 4.39] µg/dL; P = .31), total iron-binding capacity (mean difference, 4.36 [95% CI, -5.25 to 13.98] µg/dL; P = .37), or ferritin levels (mean difference, 3.0 [95% CI, -13.0 to 18.9] ng/mL; P = .71). Compared with patients who underwent LSG procedures, patients who underwent OAGB or LRYGB had higher folate levels (mean difference, 2.376 [95% CI, 1.716 to 3.036] ng/mL; P < .001) but lower serum magnesium levels (mean difference, -0.25 [95% CI, -0.35 to -0.16] mg/dL; P < .001) and zinc levels (mean difference, -7.58 [95% CI, -9.92 to -5.24] µg/dL; P < .001).

CONCLUSIONS AND RELEVANCE

These findings suggest that LSG vs OAGB or LRYGB procedures have differential associations with various micronutrient and metabolic parameters. These differences should be recognized in guidelines for postbariatric nutritional surveillance and prevention.

Survival Benefit of and Indications for Adjuvant Chemotherapy for Resected Colorectal Liver Metastases-a Japanese Nationwide Survey

BACKGROUND

The survival benefit of and indications for adjuvant chemotherapy (AC) for colorectal liver metastases (CRLM) remain unclear.

METHODS

Patients who were diagnosed with liver-limited CRLM between 2005 and 2007 and subsequently underwent R0 resection without preoperative chemotherapy were identified in a Japanese nationwide survey. This overall cohort was divided into synchronous and metachronous CRLM cohorts. In each of the three cohorts, the patients that were given AC were matched with those treated with surgery alone via 1:1 propensity score (PS) matching. Recurrence-free survival (RFS) and overall survival (OS) after the initial hepatectomy were compared.

RESULTS

The median follow-up period was 79.4 months and the overall, synchronous, and metachronous cohorts included 1145, 498, and 647 patients, respectively. After the PS matching, the patients' demographics were well balanced. AC was effective in terms of both RFS and OS in the overall cohort (RFS hazard ratio [HR] 0.784, p = 0.045; OS HR 0.716, p = 0.028) and synchronous cohort (RFS HR 0.677, p = 0.027; OS HR 0.642, p = 0.036), whereas AC was not effective in the metachronous cohort (RFS HR 0.875, p = 0.378; OS HR 0.881, p = 0.496). However, in the metachronous cohort, AC was effective in terms of OS in the subgroup that exhibited disease-free intervals of ≤ 1 year after primary tumor resection (RFS HR 0.667, p = 0.068; OS HR 0.572, p = 0.042).

CONCLUSION

Adjuvant chemotherapy has a survival benefit for patients with resected CRLM. Synchronous CRLM is a favorable indication for AC, whereas in metachronous CRLM, the use of AC should be individualized according to each patient's risk factors.

Endoscopic sphincterotomy to prevent post-ERCP pancreatitis in patients with biliary neoplasms: a multicenter retrospective cohort study

Background and aims  Treatment of biliary neoplasms often involves multiple endoscopic retrograde cholangiopancreatography (ERCP)-related procedures. Endoscopic sphincterotomy (ES) may prevent post-ERCP pancreatitis (PEP). This retrospective, multicenter cohort study aimed to investigate the effectiveness of ES for prevention of PEP in patients with biliary neoplasm. Methods  Patients with biliary duct neoplasm who underwent ERCP between January 2006 and December 2016 were enrolled. The frequency of PEP was compared between the ES and non-ES groups using propensity score analysis. The effectiveness of ES in subgroups of patients who underwent biliary duct stent placement, intraductal ultrasound (IDUS), and transpapillary biliary duct biopsy was analyzed by logistic regression. Results  Of the 362 patients enrolled, 84 (23.2 %) developed PEP. Propensity score matching for PEP risk factors in 172 ERCP procedures showed that the frequency of PEP in the ES group was lower than that in the non-ES group (19.7 % vs. 33.7 %). Non-ES was also an independent risk factor for PEP in patients who underwent intraductal ultrasound and transpapillary biliary duct biopsy (RR = 4.54 and 5.26), but was not an independent risk factor for PEP in patients with biliary duct stents. In addition, there was no evidence that the frequency of PEP was statistically different between patients with plastic stents and metal stents in the ES and non-ES groups ( P  = 0.14 and 0.10). Conclusions  ES is an effective technique to prevent PEP in patients with biliary neoplasms. In particular, ES is a safe technique to prevent PEP when performing IDUS and transpapillary biliary duct biopsy.

Database of adverse events associated with drugs and drug combinations

Due to the aging world population and increasing trend in clinical practice to treat patients with multiple drugs, adverse events (AEs) are becoming a major challenge in drug discovery and public health. In particular, identifying AEs caused by drug combinations remains a challenging task. Clinical trials typically focus on individual drugs rather than drug combinations and animal models are unreliable. An added difficulty is the combinatorial explosion in the number of possible combinations that can be made using the increasingly large set of FDA approved chemicals. We present a statistical and computational technique for identifying AEs caused by two-drug combinations. Taking advantage of the large and increasing data deposited in FDA’s postmarketing reports, we demonstrate that the task of predicting AEs for 2-drug combinations is amenable to the Likelihood Ratio Test (LRT). Our pAERS database constructed with LRT contains almost 77 thousand associations between pairs of drugs and corresponding AEs caused solely by drug-drug interactions (DDIs). The DDIs stored in pAERS complement the existing data sets. Due to our stringent statistical test, we expect many of the associations in pAERS to be unrecorded or poorly documented in the literature.

Nonrandomized studies using causal-modeling may give different answers than RCTs: a meta-epidemiological study

OBJECTIVES

To evaluate how estimated treatment effects agree between nonrandomized studies using causal modeling with marginal structural models (MSM-studies) and randomized trials (RCTs).

STUDY DESIGN

Meta-epidemiological study.

SETTING

MSM-studies providing effect estimates on any healthcare outcome of any treatment were eligible. We systematically sought RCTs on the same clinical question and compared the direction of treatment effects, effect sizes, and confidence intervals.

RESULTS

The main analysis included 19 MSM-studies (1,039,570 patients) and 141 RCTs (120,669 patients). MSM-studies indicated effect estimates in the opposite direction from RCTs for eight clinical questions (42%), and their 95% CI (confidence interval) did not include the RCT estimate in nine clinical questions (47%). The effect estimates deviated 1.58-fold between the study designs (median absolute deviation OR [odds ratio] 1.58; IQR [interquartile range] 1.37 to 2.16). Overall, we found no systematic disagreement regarding benefit or harm but confidence intervals were wide (summary ratio of odds ratios [sROR] 1.04; 95% CI 0.88 to 1.23). The subset of MSM-studies focusing on healthcare decision-making tended to overestimate experimental treatment benefits (sROR 1.44; 95% CI 0.99 to 2.09).

CONCLUSION

Nonrandomized studies using causal modeling with MSM may give different answers than RCTs. Caution is still required when nonrandomized "real world" evidence is used for healthcare decisions.

Effectiveness of endoscopic ultrasound-guided drainage for noncapsulated postoperative pancreatic collection

BACKGROUND

Postoperative pancreatic collection (POPC) is a frequent complication after pancreatectomy. Although percutaneous drainage (PD) has been the treatment of choice for POPC with encapsulation, endoscopic ultrasound-guided transmural drainage (EUS-TD) was recently reported effective for this condition. The main aim of this retrospective study was to compare EUS-TD and PD in terms of effectiveness and safety as the first procedure in patients with noncapsulated POPC.

METHODS

Consecutive patients who underwent pancreatectomy and developed noncapsulated POPC requiring EUS-TD or PD between April 2003 and May 2018 were enrolled. Noncapsulated POPC was defined as pancreatic collection appearing within 28 days postoperatively and lacking a thick encapsulating inflammatory wall on contrast-enhanced computed tomography. The effectiveness of drainage was compared between the two groups before and after propensity-score matching of patient characteristics. Outcomes of interest included re-intervention rate, number of re-interventions, immediate complication, remote complication, and time to clinical resolution after the procedure.

RESULTS

A sum of 81 patients were included: 14 underwent EUS-TD, and 67 underwent PD. There were significant differences between groups in POPC size and type of surgery. Propensity-score matching selected 13 patients who underwent EUS-TD and 28 who underwent PD. Re-intervention rate (p = 0.045), and number of re-interventions (p = 0.026) were significantly lower in the matched EUS-TD group than in the matched PD group. There were no significant between-group differences in immediate complication and remote complication. The time to clinical resolution after the procedure was significantly shorter in the matched EUS-TD than in the matched PD group (14 versus 26 days; p < 0.0001).

CONCLUSION

EUS-TD is more effective than PD for drainage of noncapsulated POPC. EUS-TD should be considered as the first treatment of choice for noncapsulated POPC visible on EUS.

What is the Best Option Between Primary Diverting Stoma or Endoscopic Stent as a Bridge to Surgery with a Curative Intent for Obstructed Left Colon Cancer? Results from a Propensity Score Analysis of the French Surgical Association Multicenter Cohort of 518 Patients

BACKGROUND

Endoscopic stent (ES) as a bridge to surgery in obstructed left colon cancer (OLCC) is controversial. Our goal was to compare the operative and oncological results of primary diverting colostomy (PDC) and ES for the curative treatment of OLCC.

METHODS

Between 2000 and 2015, patients who underwent PDC or ES in a curative intent for OLCC at member centers of the French Surgical Association were included. Patients with unresectable tumors and/or synchronous metastases were excluded. Comparisons between the two groups were performed after ponderation with propensity score for: demographic and tumor characteristics, operative, and oncological results.

RESULTS

A total of 518 patients were included: PDC (n = 327); ES (n = 191). The demographic characteristics were similar between the groups. ES failed in 23% of the patients (11% perforation). Cumulative tumor resection rates were 80% and 86% after PDC and ES, respectively (p = 0.049). The rates of primary anastomosis were 57% in the PDC group and 40% in the ES group (p < 0.0001). The permanent stoma rates were similar between the two groups (29% vs. 28%, p = 0.0586). Cumulative overall, surgical, and medical complications were significantly higher in PDC group. The resected tumors were significantly smaller and less frequently perforated and metastatic in the PDC group. The median overall survival was significantly higher after PDC (123.6 vs. 58.5 months, p = 0.046), whereas the median disease-free survival was similar between the two groups (54.1 vs. 53.6 months, p = 0.646).

CONCLUSIONS

Although endoscopic stenting is associated with better surgical outcomes than diverting stoma, it may negatively impact histological features and overall survival.

Comparative efficacy of first-line ceritinib and crizotinib in advanced or metastatic anaplastic lymphoma kinase-positive non-small cell lung cancer: an adjusted indirect comparison with external controls

Objective: In the absence of head-to-head trials, this study indirectly compared progression free survival (PFS) and overall survival (OS) between ceritinib and crizotinib among patients with previously untreated advanced anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC).Methods: A matching-adjusted indirect comparison method was implemented to adjust for cross-trial differences in patient characteristics between ASCEND-4 and PROFILE 1014 trials. Patient-level data from ASCEND-4 and published summary data from PROFILE 1014 were used. Patients in ASCEND-4 were reweighted to match average baseline characteristics (i.e. age, sex, race, tumor histology, ECOG score, smoking status, extent of disease, and presence of brain metastases) reported for PROFILE 1014 patients using propensity score weighting. PFS and OS were then compared between balanced populations.Results: ASCEND-4 included more current smokers (8.0% vs 4.4%) and fewer patients under the age of 65 years (78.5% vs 84.0%) compared to PROFILE 1014. After matching, these and all other patient characteristics were balanced between the two trial populations. Compared to crizotinib, ceritinib was associated with a significantly longer PFS (hazard ratio [95% confidence interval] (HR [CI]) = 0.64 [0.47-0.87]; median PFS: 25.2 vs 10.8 months, log-rank p-value = 0.003). OS did not differ significantly, with a HR of 0.82 [0.54-1.27] for ceritinib compared to crizotinib.Conclusions: In the adjusted indirect comparison with external controls, the second generation ALK inhibitor, ceritinib, was associated with a significantly prolonged PFS compared to crizotinib as first-line treatment for ALK-positive NSCLC.

Economic value of orthotic and prosthetic services among medicare beneficiaries: a claims-based retrospective cohort study, 2011-2014

Background

There are few studies of the economic value of orthotic and prosthetic services. A prior cohort study of orthotic and prosthetic Medicare beneficiaries based on Medicare Parts A and B claims from 2007 to 2010 concluded that patients who received timely orthotic or prosthetic care had comparable or lower total health care costs than a comparison group of untreated patients. This follow-up study reports on a parallel analysis based on Medicare claims from 2011 to 2014 and includes Part D in addition to Parts A and B services and expenditures. Its purpose is to validate earlier findings on the extent to which Medicare patients who received select orthotic and prosthetic services had less health care utilization, lower Medicare payments, and potentially fewer negative outcomes compared to matched patients not receiving these services.

Methods

This is a retrospective cohort analysis of 78,707 matched pairs of Medicare beneficiaries with clinical need for orthotic and prosthetic services (N = 157,414) using 2011–2014 Medicare claims data. It uses propensity score matching techniques to control for observable selection bias. Economically, a cost-consequence evaluation over a four-year time horizon was performed.

Results

Patients who received lower extremity orthotics had 18-month episode costs that were $1939 lower than comparable patients who did not receive orthotic treatment ($22,734 vs $24,673). Patients who received spinal orthotic treatment had 18-month episode costs that were $2094 lower than comparable non-treated patients ($23,560 vs $25,655). Study group beneficiaries receiving both types of orthotics had significantly lower Part D spending than those not receiving treatment (p < 0.05). Patients who received lower extremity prostheses had comparable 15-month episode payments to matched beneficiaries not receiving prostheses ($68,877 vs $68,893) despite the relatively high cost of the prosthesis.

Conclusions

These results were consistent with those found in the prior study and suggest that orthotic and prosthetic services provide value to the Medicare program and to the patient.

Association of Whole-Body Computed Tomography With Mortality Risk in Children With Blunt Trauma

IMPORTANCE

Although several studies have demonstrated an improvement in mortality for injured adults who receive whole-body computed tomography (WBCT), it is unclear whether children experience the same benefit.

OBJECTIVE

To determine whether emergent WBCT is associated with lower mortality among children with blunt trauma compared with a selective CT approach.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective, multicenter cohort study was conducted from January 1, 2010, to December 31, 2014, using data from the National Trauma Data Bank on children aged 6 months to 14 years with blunt trauma who received an emergent CT scan in the first 2 hours after emergency department arrival. Data analysis was conducted from February 2 to December 29, 2017.

EXPOSURES

Patients were classified as having WBCT if they received CT head, CT chest, and CT abdomen/pelvis scans in the first 2 hours and as having a selective CT if they did not receive all 3 scans.

MAIN OUTCOMES AND MEASURES

The primary outcome was in-hospital mortality in the 7 days after ED arrival. To adjust for potential confounding, propensity score weighting was used. Subgroup analyses were performed for those with the highest mortality risk (ie, occupants and pedestrians involved in motor vehicle crashes, children with a Glasgow Coma Scale score lower than 9, children with hypotension, and those admitted to the intensive care unit).

RESULTS

Of the 42 912 children included in the study (median age [interquartile range], 9 [5-12] years; 27 861 [64.9%] boys), 8757 (20.4%) received a WBCT. Overall, 405 (0.9%) children died within 7 days. After adjusting for the propensity score, children who received WBCT had no significant difference in mortality compared with those who received selective CT (absolute risk difference, -0.2%; 95% CI, -0.6% to 0.1%). All subgroup analyses similarly showed no significant association between WBCT and mortality.

CONCLUSIONS AND RELEVANCE

Among children with blunt trauma, WBCT, compared with a selective CT approach, was not associated with lower mortality. These findings do not support the routine use of WBCT for children with blunt trauma.

Choice of time period to identify confounders for propensity score matching, affected the estimate: a retrospective cohort study of drug effectiveness in asthmatic children

OBJECTIVES

To control for confounding by indication in comparative (drug) effectiveness studies, propensity score (PS) methods may be used. Since childhood diseases or outcomes often present as acute events, we compared the effect of using different look-back periods in electronic health-care data, to construct PSs. This was applied in our research on the effect of a combination of inhaled corticosteroids/long-acting beta-2 agonists (ICS + LABA), either as fixed combination or used as loose combination (2 separate inhaler devices) in the prevention of severe asthma exacerbations.

METHODS

We created a cohort of children (5-17 years) diagnosed with asthma from the Dutch Integrated Primary Care information database. Within this cohort, we identified new users of ICS + LABA, either as fixed combination or loose combination (2 separate inhaler devices). The outcome of interest was severe asthma exacerbations. PSs for type of treatment were created using comorbidity and drug use history in different time windows: 1 week, 1 month, 3 months, 1 year, and full history prior to the start of treatment. PSs were used for matching subjects in both exposure groups. Time to first asthma exacerbation was analyzed with Cox proportional hazard regression. The results were compared with published clinical trials.

RESULTS

Of 39,682 asthmatic children, 3,500 (8.8%) were new users of either ICS + LABA fixed (3,324 [95.0%]) or loose (176 [5.0%]). The crude hazard ratio (HR) for a severe asthma exacerbation, comparing ICS + LABA fixed to loose was 0.37 (95% confidence interval [CI]: 0.20-0.66). PS-matched HRs (1 week, 1 month, 3 month, 1 year, and full history) were 0.48 (95% CI: 0.22-1.04); 0.60 (95% CI: 0.26-1.38), 0.69 (95% CI: 0.31-1.57), 0.56 (CI: 0.25-1.24), and 0.58 (CI: 0.24-1.36), respectively.

CONCLUSIONS

PS matching can be used to control for confounding in pediatric comparative (drug) effectiveness studies, the impact of different look-back periods to implement the PS is important. Controlling for confounders occurring in the 3 months preceding drug exposure may yield results comparable to clinical trial results.

Meta-Analysis Comparing ≥10-Year Mortality of Off-Pump Versus On-Pump Coronary Artery Bypass Grafting

Off-pump coronary artery bypass grafting (CABG) is suggested to be associated with an increase in long-term (≥5-year) all-cause mortality. To determine whether off-pump CABG is associated with an increase in very long-term (≥10-year) all-cause mortality, we performed a meta-analysis of propensity-score matched observational comparative studies of off-pump versus on-pump CABG. MEDLINE and EMBASE were searched through May 2017. A hazard ratio of follow-up (including early) all-cause mortality for off-pump versus on-pump CABG was extracted from each individual study. Study-specific estimates were combined using inverse variance-weighted averages of logarithmic hazard ratios in the random-effects model. Of 164 potentially relevant studies, our search identified 16 propensity-score matched observational comparative studies of off-pump versus on-pump CABG with ≥10-year follow-up enrolling a total of 82,316 patients. A pooled analysis of all the 16 studies demonstrated that off-pump CABG was significantly associated with an increase in all-cause mortality (hazard ratio 1.07, 95% confidence interval 1.03 to 1.12, p for effect = 0.0008; p for heterogeneity = 0.30, I² = 12%). In a sensitivity analysis, exclusion of any single hazard ratio from the analysis (leave-one-out meta-analysis) did not substantively alter the overall result. There was no evidence of a significant publication bias. In conclusion, off-pump CABG is associated with an increase in very long-term (≥10 years) all-cause mortality compared with on-pump CABG.

What is the best setting for receiving dialysis vascular access repair and maintenance services?

INTRODUCTION

Advances in dialysis vascular access (DVA) management have changed where beneficiaries receive this care. The effectiveness, safety, quality, and economy of different care settings have been questioned. This study compares patient outcomes of receiving DVA services in the freestanding office-based center (FOC) to those of the hospital outpatient department (HOPD). It also examines whether outcomes differ for a centrally managed system of FOCs (CMFOC) compared to all other FOCs (AOFOC).

METHODS

Retrospective cohort study of clinically and demographically similar patients within Medicare claims available through United States Renal Data System (USRDS) (2010-2013) who received at least 80% of DVA services in an FOC (n = 80,831) or HOPD (n = 133,965). Separately, FOC population is divided into CMFOC (n = 20,802) and AOFOC (n = 80,267). Propensity matching was used to control for clinical, demographic, and functional characteristics across populations.

RESULTS

FOC patients experienced significantly better outcomes, including lower annual mortality (14.6% vs. 17.2%, p<0.001) and DVA-related infections (0.16 vs. 0.20, p<0.001), fewer hospitalizations (1.65 vs. 1.91, p<0.001), and lower total per-member-per-month (PMPM) payments ($5042 vs. $5361, p<0.001) than HOPD patients. CMFOC patients had lower annual mortality (12.5% vs. 13.8%, p<0.001), PMPM payments (DVA services) ($1486 vs. $1533, p<0.001) and hospitalizations ($1752 vs. $1816, p<0.001) than AOFOC patients.

CONCLUSIONS

Where nephrologists send patients for DVA services can impact patient clinical and economic outcomes. This research confirmed that patients who received DVA care in the FOC had better outcomes than those treated in the HOPD. The organizational culture and clinical oversight of the CMFOC may result in more favorable outcomes than receiving care in AOFOC.

Outcomes of Hemiepiphyseal Stapling for Genu Valgum Deformities in Patients With Multiple Hereditary Exostoses: A Comparative Study of Patients With Deformities of Idiopathic Cause

BACKGROUND

Patients with multiple hereditary exostoses (MHE) frequently present with a genu valgum deformity. Temporary hemiepiphysiodesis, such as hemiepiphyseal stapling, is a relatively safe surgical method to correct angular deformities in skeletally immature patients, but its outcomes for genu valgum deformity in MHE patients have not been extensively reported. We investigated the outcomes of hemiepiphyseal stapling in MHE patients (MHE group) and compared those with the outcomes in patients with idiopathic deformities (idiopathic group) after adjusting for potential bias.

METHODS

Data from 70 limbs with genu valgum deformity (15 MHE and 55 idiopathic), which had undergone hemiepiphyseal stapling, were retrospectively reviewed. The outcomes were focused on the achievement of satisfactory correction and the velocity of correction. The independent effects of each characteristic on each outcome were investigated using multivariate analyses. The outcomes between the groups were also compared after 1:2 matching using propensity score analysis.

RESULTS

The mean valgus angle of the MHE group was 7.4±4.1 degrees at stapling and was corrected to 1.3±3.0 degrees at staple removal. The rate of satisfactory corrections was not different between the MHE and idiopathic groups (67% and 70%, respectively, P=0.820). However, the correction velocity was significantly lower in the MHE group than in the idiopathic group on both multivariate analysis (P=0.001) and matching comparison (4.4 vs. 7.9 degrees/y, P<0.001). The duration of correction was longer in the MHE group than in the idiopathic group by approximately half a year (1.5±0.6 vs. 0.9±0.3 y, respectively, P=0.003).

CONCLUSIONS

In MHE patients with genu valgum deformity, satisfactory correction can be achieved by hemiepiphyseal stapling and is comparable with that seen in idiopathic patients. However, the MHE group showed lower correction velocity and required a longer time by about one half year for correction compared with the idiopathic group. Temporary hemiepiphysiodesis should be considered at an earlier age for patients with MHE compared with those with idiopathic deformity.

LEVEL OF EVIDENCE

Level III-prognostic study.

Alpha-fetoprotein is a significant prognostic factor for gastric cancer: Results from a propensity score matching analysis after curative resection

BACKGROUND

Prognosis of alpha-fetoprotein positive gastric cancer (AFPP-GC) remains elusive so far due to disparities in cohort size and baseline characteristics in previous studies. A propensity score matching (PSM) analysis as well as multivariable model was performed for unbiased evaluation of the outcome in AFPGC.

METHODS

Among 3034 gastric cancer patients who underwent curative gastric cancer surgery (R0, M0) at the National Cancer Center, Korea between 2002 and 2007, we identified 97 patients being positive for AFP either by elevation of serum-AFP levels >10 μg/L or by immunohistochemical staining. Due to marked disparities in baseline characteristics and cohort size, propensity-score-matching was performed which matched 87 AFPP-GC patients to the same number of AFP-negative gastric cancer (AFPN-GC) patients. Baseline characteristics were compared using χ²-test. Survival curves were compared using the Kaplan-Meier-method and multivariable regression analysis was performed to evaluate the effect of AFP-positivity while adjusting the effects of confounding variables.

RESULTS

AFPP-GC and AFPN-GC patients revealed marked disparities in patient cohorts. After PSM, groups were balanced for age, sex, tumor size, BMI, tumor location, grade of differentiation, presence of lymphatic vessel infiltration (LVI), Lauren histologic type and stage distribution. In multivariable regression analysis of the PSM-groups, only AFP-positivity and pathologic stage were predictive for overall survival (HR 2.98, CI 95% {1.7-5.1}, p < 0.0001). Five-year-survival rates were significantly worse for AFPP-GC patients (57.9% vs. 76.1%, p = 0.014). Recurrence was significantly more frequent in AFPP-GC patients (p = 0.003).

CONCLUSION

AFP can be considered as an independent negative predictor of overall and recurrence-free survival in patients with gastric cancer.

Splenic preservation in laparoscopic distal pancreatectomy

Background

Laparoscopic spleen-preserving distal pancreatectomy (LSPDP) is designed principally for the removal of benign and low-grade malignant lesions in the left pancreas. The aims of this study were to compare LSPDP with laparoscopic distal pancreatectomy with splenectomy (LDPS), compare two splenic preservation techniques (splenic vessel preservation and Warshaw technique) and investigate factors that influence splenic preservation.

Methods

Information from patients who underwent laparoscopic distal pancreatectomy between December 2004 and January 2016 at a single institution was reviewed. Data were extracted from a prospectively developed database. Intention-to-treat and propensity score matching analyses were employed. Univariable and multivariable analyses were used to investigate factors affecting splenic preservation.

Results

There were 206 patients in total (126 planned LSPDP and 80 planned LDPS procedures), of whom 108 underwent LSPDP and 98 LDPS. In intention-to-treat analysis, the duration of surgery was significantly shorter in the LSPDP group than in the LDPS group (mean 191·0 versus 220·5 min respectively; P &lt; 0·001). Tumour size was an independent risk factor for splenic vessel resection in planned splenic vessel preservation operations, and a cut-off value of 3 cm provided optimal diagnostic accuracy. After a median follow-up of 35·9 months, there were no clinically significant splenic infarctions and no patient developed gastrointestinal bleeding after LSPDP.

Conclusion

Planned LSPDP had a high splenic preservation rate and was associated with significantly shorter operating time than LDPS. Splenic vessel preservation could be predicted using a tumour cut-off size of 3 cm.

Perioperative transfusion of leukocyte depleted blood products in gastric cancer patients negatively influences oncologic outcome: A retrospective propensity score weighted analysis on 610 curatively resected gastric cancer patients

The influence of perioperative transfusion (PT) on outcome following surgery for gastric cancer (GC) remains controversial, with randomized trials lacking and observational series confounded by patient risk factors. This analysis determines the association between reception of leukocyte-depleted blood products and post-operative survival for GC.Data from 610 patients who underwent curative surgery for GC in a German tertiary care clinic from 2001 to 2013 were included. Kaplan-Meier survival curves and Cox proportional hazards regression were applied to determine the association of PT and clinical and patient risk factors for overall and relapse-free survival. Propensity score analysis was performed to adjust for observational biases in reception of PT.Higher Union International Contre le Cancer/American Joint Committee on Cancer (UICC/AJCC)-stages (P <0.001), postoperative complications and severity according to the Clavien-Dindo (CD) classification (P <0.001), PT (P = 0.02), higher age (P <0.001), and neoadjuvant chemotherapy (P <0.001) were related to increased mortality rates. Higher UICC-stages (P <0.001), neoadjuvant chemotherapy (P <0.001), and type of surgery (P = 0.02) were independently associated with increased relapse rates. Patients were more likely to receive PT with higher age (P = 0.05), surgical extension to adjacent organs/structures (P = 0.002), tumor location (P = 0.003), and female gender (P = 0.03). In the adjusted propensity score weighted analysis, PT remained associated with an increased risk of death (hazard ratio (HR): 1.31, 95% CI: 1.01-1.69, P = 0.04).Because of the association of PT with negative influence on patient survival following resection for GC, risks from application of blood products should be weighed against the potential benefits.

Different survival outcomes after curative R0-resection for Eastern Asian and European gastric cancer: Results from a propensity score matched analysis comparing a Korean and a German specialized center

Several retrospective analyses on patients who underwent gastric cancer (GC) surgery revealed different survival outcomes between Eastern (Korean, Japanese) and Western (USA, Europe) countries due to potential ethnical and biological differences. This study investigates treatment outcomes between specialized institution for GC in Korea and Germany.The prospectively documented databases of the Gastric Cancer Center of the National Cancer Center, Korea (NCCK) and the Department of Surgery of the Technische Universitaet Muenchen (TUM), Germany were screened for patients who underwent primary surgical resection for GC between 2002 and 2008. Baseline characteristics were compared using χ testing, and 2 cohorts were matched using a propensity score matching (PSM) method. Patients' survival was estimated using Kaplan-Meier method, and multivariable Cox proportional hazard model was used for comparison.Three thousand seven hundred ninety-five patients were included in the final analysis, 3542 from Korea and 253 from Germany. Baseline characteristics revealed statistically significant differences for age, tumor location, pT stage, grading, lymphatic vessel infiltration (LVI), comorbidities, number of dissected lymph nodes (LN), postoperative complications, lymph-node ratio stage, and application of adjuvant chemotherapy. After PSM, 171 patients in TUM were matched to NCCK patients, and baseline characteristics for both cohorts were well balanced. Patients in Korea had significantly longer survival than those in Germany both before and after PSM. When the analysis was performed for each UICC stage separately, same trend was found over all UICC stages before PSM. However, significant difference in survival was observed only for UICC I after PSM.This analysis demonstrates different survival outcomes after surgical treatment of GC on different continents in specialized centers after balancing of baseline characteristics by PSM.