Individual participant data meta-analysis of intervention studies with time-to-event outcomes: A review of the methodology and an applied example

The Impact of Portal Hypertension Assessment Method on the Outcomes of Hepatocellular Carcinoma Resection: A Meta-Analysis of Matched Cohort and Prospective Studies

OBJECTIVE

Examine portal hypertension (PHT) impact on postoperative and survival outcomes in hepatocellular carcinoma (HCC) patients after liver resection (LR), specifically exploring distinctions between indirect signs and invasive measurements of PHT.

BACKGROUND

PHT has historically discouraged LR in individuals with HCC due to the elevated risk of morbidity, including liver decompensation (LD).

METHODS

A systematic review was conducted using 3 databases to identify prospective-controlled and matched cohort studies until December 28, 2022. Focus on comparing postoperative outcomes (mortality, morbidity, and liver-related complications) and overall survival in HCC patients with and without PHT undergoing LR. Three meta-analysis models were utilized: for aggregated data (fixed-effects inverse variance model), for patient-level survival data (one-stage frequentist meta-analysis with gamma-shared frailty Cox proportional hazards model), and for pooled data (Freeman-Tukey exact and double arcsine method).

RESULTS

Nine studies involving 1124 patients were analyzed. Indirect signs of PHT were not significantly associated with higher mortality, overall complications, PHLF or LD. However, LR in patients with hepatic venous pressure gradient (HVPG) ≥10 mm Hg significantly increased the risk of overall complications, PHLF, and LD. Despite elevated risks, the procedure resulted in a 5-year overall survival rate of 55.2%. Open LR significantly increased the risk of overall complications, PHLF, and LD. Conversely, PHT did not show a significant association with worse postoperative outcomes in minimally invasive LR.

CONCLUSIONS

LR in the presence of indirect signs of PHT poses no increased risk of complications. Yet, in HVPG ≥10 mm Hg patients, LR increases overall morbidity and liver-related complications risk. Transjugular HVPG assessment is crucial for LR decisions. Minimally invasive approach seems to be vital for favorable outcomes, especially in HVPG ≥10 mm Hg patients.

Mitomycin C 0.2 mg/ml vs. Mitomycin C 0.4mg/ml during the implantation of an ab externo SIBS microshunt: A mega-analysis

PURPOSE

To compare the effectiveness and adverse event profile of standalone SIBS microshunt implantation with adjunct MMC 0.2 mg/ml and MMC 0.4 mg/ml.

DESIGN

Mega-analysis using individual patient data from international prospective and retrospective clinical studies.

STUDY POPULATION

Patients with glaucoma who underwent implantation of a SIBS microshunt with MMC as a standalone procedure.

METHODS

A comparison of eyes that received MMC 0.2 mg/ml or 0.4 mg/ml MAIN OUTCOMES MEASURES: Primary outcome was complete success defined as the proportion of eyes at one year with all of the following: (1) no two consecutive IOPs > 17 mmHg; (2) no clinical hypotony (3) ≥20% IOP reduction from baseline and (4) no use of glaucoma medications. Secondary outcomes included IOP thresholds of 12 mmHg,14 mm Hg and 21mmHg, median IOP, number of medications, risk factors for failure, interventions, adverse events, and reoperations.

RESULTS

At 1 year, the complete success rate was significantly higher (71.3% vs 50.46%, p<0.001) and the median IOP significantly lower (13.0 vs. 14.2 mmHg, p<0.05) in the MMC 0.4 mg/ml group. MMC 0.2 mg/ml was found to be a significant risk factor for failure (HR 1.75 95%CI 1.14 to 2.67). Needling and surgical revision occurred at a lower rate in the MMC 0.4 mg/ml group (7% vs. 18.8%, p= 0.002 and 4.3% vs.13.7% p= 0.0087, respectively). Adverse events occurred at a similar frequency in both groups (26.6% MMC 0.2 mg/ml vs. 29.6% MMC 0.4 mg/ml, p=0.46), most of which were early and transient.

CONCLUSION

SIBS microshunt implantation with MMC 0.4 mg/ml resulted in a higher success rate with greater IOP reduction compared to MMC 0.2 mg/ml. Higher MMC concentration was not associated with increased serious adverse events.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Bayesian pairwise meta-analysis of time-to-event outcomes in the presence of non-proportional hazards: A simulation study of flexible parametric, piecewise exponential and fractional polynomial models

BACKGROUND

Traditionally, meta-analysis of time-to-event outcomes reports a single pooled hazard ratio assuming proportional hazards (PH). For health technology assessment evaluations, hazard ratios are frequently extrapolated across a lifetime horizon. However, when treatment effects vary over time, an assumption of PH is not always valid. The Royston-Parmar (RP), piecewise exponential (PE), and fractional polynomial (FP) models can accommodate non-PH and provide plausible extrapolations of survival curves beyond observed data.

METHODS

Simulation study to assess and compare the performance of RP, PE, and FP models in a Bayesian framework estimating restricted mean survival time difference (RMSTD) at 50 years from a pairwise meta-analysis with evidence of non-PH. Individual patient data were generated from a mixture Weibull distribution. Twelve scenarios were considered varying the amount of follow-up data, number of trials in a meta-analysis, non-PH interaction coefficient, and prior distributions. Performance was assessed through bias and mean squared error. Models were applied to a metastatic breast cancer example.

RESULTS

FP models performed best when the non-PH interaction coefficient was 0.2. RP models performed best in scenarios with complete follow-up data. PE models performed well on average across all scenarios. In the metastatic breast cancer example, RMSTD at 50-years ranged from -14.6 to 8.48 months.

CONCLUSIONS

Synthesis of time-to-event outcomes and estimation of RMSTD in the presence of non-PH can be challenging and computationally intensive. Different approaches make different assumptions regarding extrapolation and sensitivity analyses varying key assumptions are essential to check the robustness of conclusions to different assumptions for the underlying survival function.

Protocol for an independent patient data meta-analysis of prophylactic mesh placement for incisional hernia prevention after abdominal aortic aneurysm surgery: a collaborative European Hernia Society project (I-PREVENT-AAA)

INTRODUCTION

Incisional hernia (IH) is a prevalent and potentially dangerous complication of abdominal surgery, especially in high-risk groups. Mesh reinforcement of the abdominal wall has been studied as a potential intervention to prevent IHs. Randomised controlled trials (RCTs) have demonstrated that prophylactic mesh reinforcement after abdominal surgery, in general, is effective and safe. In patients with abdominal aortic aneurysm (AAA), prophylactic mesh reinforcement after open repair has not yet been recommended in official guidelines, because of relatively small sample sizes in individual trials. Furthermore, the identification of subgroups that benefit most from prophylactic mesh placement requires larger patient numbers. Our primary aim is to evaluate the efficacy and effectiveness of the use of a prophylactic mesh after open AAA surgery to prevent IH by performing an individual patient data meta-analysis (IPDMA). Secondary aims include the evaluation of postoperative complications, pain and quality of life, and the identification of potential subgroups that benefit most from prophylactic mesh reinforcement.

METHODS AND ANALYSIS

We will conduct a systematic review to identify RCTs that study prophylactic mesh placement after open AAA surgery. Cochrane Central Register of Controlled Trials, MEDLINE Ovid, Embase, Web of Science Core Collection and Google Scholar will be searched from the date of inception onwards. RCTs must directly compare primary sutured closure with mesh closure in adult patients who undergo open AAA surgery. Lead authors of eligible studies will be asked to share individual participant data (IPD). The risk of bias (ROB) for each included study will be assessed using the Cochrane ROB tool. An IPDMA will be performed to evaluate the efficacy, with the IH rate as the primary outcome. Any signs of heterogeneity will be evaluated by Forest plots. Time-to-event analyses are performed using Cox regression analysis to evaluate risk factors.

ETHICS AND DISSEMINATION

No new data will be collected in this study. We will adhere to institutional, national and international regulations regarding the secure and confidential sharing of IPD, addressing ethics as indicated. We will disseminate findings via international conferences, open-source publications in peer-reviewed journals and summaries posted online.

PROSPERO REGISTRATION NUMBER

CRD42022347881.

Appropriateness of conducting and reporting random-effects meta-analysis in oncology

A random-effects model is often applied in meta-analysis when considerable heterogeneity among studies is observed due to the differences in patient characteristics, timeframe, treatment regimens, and other study characteristics. Since 2014, the journals Research Synthesis Methods and the Annals of Internal Medicine have published a few noteworthy papers that explained why the most widely used method for pooling heterogeneous studies-the DerSimonian-Laird (DL) estimator-can produce biased estimates with falsely high precision and recommended to use other several alternative methods. Nevertheless, more than half of studies (55.7%) published in top oncology-specific journals during 2015-2022 did not report any detailed method in the random-effects meta-analysis. Of the studies that did report the methodology used, the DL method was still the dominant one reported. Thus, while the authors recommend that Research Synthesis Methods and the Annals of Internal Medicine continue to increase the publication of its articles that report on specific methods for handling heterogeneity and use random-effects estimates that provide more accurate confidence limits than the DL estimator, other journals that publish meta-analyses in oncology (and presumably in other disease areas) are urged to do the same on a much larger scale than currently documented.

Psychological Distress and the Risk of Adverse Cardiovascular Outcomes in Patients With Coronary Heart Disease

BACKGROUND

Psychological distress is a recognized risk factor in patients with coronary heart disease (CHD), but its clinical significance is unclear.

OBJECTIVES

The purpose of this study was to determine if an index of psychological distress is independently associated with adverse outcomes and significantly contributes to risk prediction.

METHODS

Pooled analysis of 2 prospective cohort studies of patients with stable CHD (N = 891). A psychological distress score was constructed using measures of depression, anxiety, anger, perceived stress, and post-traumatic stress disorder, measured at baseline. The study endpoint included cardiovascular death or first or recurrent nonfatal myocardial infarction or hospitalization for heart failure at 5.9 years.

RESULTS

In both cohorts, first and recurrent events occurred more often among those in the highest tertile of distress score than those in the lowest tertile. After combining the 2 cohorts, compared with the lowest tertile, the hazards ratio for having a distress score in the highest tertile was 2.27 (95% CI: 1.69-3.06), and for the middle tertile, it was 1.52 (95% CI: 1.10-2.08). Adjustment for demographics and clinical risk factors only slightly weakened the associations. When the distress score was added to a traditional clinical risk model, C-statistic, net reclassification index, and integrative discrimination index all significantly improved.

CONCLUSIONS

Among patients with CHD, a composite measure of psychological distress was significantly associated with an increased risk of adverse events and significantly improved risk prediction.

Survival and safety after neoadjuvant chemotherapy or upfront surgery for locally advanced colon cancer: meta-analysis

BACKGROUND

Neoadjuvant chemotherapy is increasingly used to treat locally advanced (T3-4 Nx-2 M0) colon cancer due to its potential advantages over the standard approach of upfront surgery. The primary objective of this systematic review and meta-analysis was to analyse data from comparative studies to assess the impact of neoadjuvant chemotherapy on oncological outcomes.

METHODS

A systematic review was conducted by searching the MEDLINE and Scopus databases. The search encompassed RCTs, propensity score-matched studies, and controlled prospective studies published up to 1 April 2023. As a primary objective, overall survival and disease-free survival were compared. As a secondary objective, perioperative morbidity, mortality, and complete resection were compared using the DerSimonian and Laird models.

RESULTS

A total of seven studies comprising a total of 2120 patients were included. Neoadjuvant chemotherapy was associated with a reduction in the hazard of recurrence (HR 0.73, 95% c.i. 0.59 to 0.90; P = 0.003) and death (HR 0.67, 95% c.i. 0.54 to 0.83; P < 0.001) compared with upfront surgery. Additionally, neoadjuvant chemotherapy was significantly associated with higher 5-year overall survival (79.9% versus 72.6%; P < 0.001) and disease-free survival (73.1% versus 64.5%; P = 0.028) rates. No significant differences were observed in perioperative mortality (OR 0.97, 95% c.i. 0.28 to 3.33), overall complications (OR 0.95, 95% c.i. 0.77 to 1.16), or anastomotic leakage/intra-abdominal abscess (OR 0.88, 95% c.i. 0.60 to 1.29). However, neoadjuvant chemotherapy was associated with a lower risk of incomplete resection (OR 0.70, 95% c.i. 0.49 to 0.99).

CONCLUSION

Neoadjuvant chemotherapy is associated with a reduced hazard of recurrence and death, as well as improved overall survival and disease-free survival rates, compared with upfront surgery in patients with locally advanced colon cancer.

Real-World Outcomes with Chimeric Antigen Receptor T Cell Therapies in Large B Cell Lymphoma: A Systematic Review and Meta-Analysis

Chimeric antigen receptor T cell (CAR-T) therapies, including axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel), are innovative treatments for patients with relapsed or refractory (r/r) large B cell lymphoma (LBCL). Following initial regulatory approvals, real-world evidence (RWE) of clinical outcomes with these therapies has been accumulating rapidly. Notably, several large registry studies have been published recently. Here we comprehensively describe clinical outcomes with approved CAR-T therapies in patients with r/r LBCL using available RWE. We systematically searched Embase, MEDLINE, and 15 conference proceedings to identify studies published between 2017 and July 2022 that included ≥10 patients with r/r LBCL treated with commercially available CAR-T therapies. Eligible study designs were retrospective or prospective observational studies. Key outcomes of interest were objective response rate (ORR), complete response (CR) rate, overall survival (OS), progression-free survival (PFS), cytokine release syndrome (CRS), and immune effector cell-associated neurotoxicity syndrome (ICANS). Random-effects meta-analyses were used to compare real-world outcomes with those of pivotal clinical trials and to compare clinical outcomes associated with axi-cel and tisa-cel. Study cohort mapping was conducted to avoid including patients more than once. Of 76 cohorts we identified, 46 reported patients treated specifically with either axi-cel or tisa-cel, with 39 cohorts (n = 2754 patients) including axi-cel and 20 (n = 1649) including tisa-cel. No studies of liso-cel that met the inclusion criteria were identified during the search period. One-half of the tisa-cel cohorts were European, compared with 33% of the axi-cel cohorts. Among studies with available data, axi-cel had a significantly shorter median time from apheresis to CAR-T infusion than tisa-cel. Despite including broader patient populations, real-world effectiveness and safety of both axi-cel and tisa-cel were consistent with data from the pivotal clinical trials. Comparative meta-analysis of axi-cel versus tisa-cel demonstrated adjusted hazard ratios for OS and PFS of .60 (95% confidence interval [CI], .47 to .77) and .67 (95% CI, .57 to .78), respectively, both in favor of axi-cel. Odds ratios (ORs) for ORR and CR rate, both favoring axi-cel over tisa-cel, were 2.05 (95% CI, 1.76 to 2.40) and 1.70 (95% CI, 1.46 to 1.96), respectively. The probability of grade ≥3 CRS was comparable with axi-cel and tisa-cel, whereas axi-cel was associated with a higher incidence of grade ≥3 ICANS (OR, 3.95; 95% CI, 3.05 to 5.11). Our meta-analysis indicates that CAR-T therapies have manageable safety profiles and are effective in a wide range of patients with r/r LBCL, and that axi-cel is associated with improved OS and PFS and increased risk of grade ≥3 ICANS compared with tisa-cel. Limitations of this study include nonrandomized treatments, potential unknown prognostic factors, and the lack of available real-world data for liso-cel.

How to plan and manage an individual participant data meta-analysis. An illustrative toolkit

Individual participant data meta-analyses (IPD-MAs) have several benefits over standard aggregate data meta-analyses, including the consideration of additional participants, follow-up time, and the joint consideration of study- and participant-level heterogeneity for improved diagnostic and prognostic model development and evaluation. However, IPD-MAs are resource-intensive and require careful budgeting of time from data contributing groups, a dedicated management team, diversity of expertise, clearly documented data sharing and authorship agreements, and consistent and clear communication. We present a toolkit to facilitate the implementation and management of IPD-MAs, from study recruitment to retrospective harmonization. The toolkit was developed and refined over our work on multiple multinational IPD-MA projects over the last 13 years. The toolkit's budget and email templates, agreements, project management spreadsheets, and standard operating procedures are meant to facilitate routine IPD-MA tasks to expedite implementing and managing future IPD-MA projects.

Surgery for liver metastases from primary breast cancer: A reconstructed individual patient data meta-analysis

BACKGROUND

Currently, the outcomes of standard-of-care palliative treatment for BCLM remain poor. Recent literature has shown promising results of hepatic resection, however, not all studies concur. Given the lack of standardized international guidelines in this field, the aim of this study is to provide gold-standard evidence for breast cancer liver metastases (BCLM) through a reconstructed individual patient data meta-analysis approach.

METHODS

Four databases were searched for articles comparing surgical and non-surgical treatment for BCLM. One-stage meta-analysis was performed using patient-level survival data reconstructed from Kaplan-Meier curves with plot digitizer software. Shared-frailty and stratified Cox models were fitted to compare survival endpoints.

RESULTS

Four propensity-score matched (PSM) studies involving 205 surgical and 291 non-surgical patients for BCLM were included. There was a significant difference between both groups for overall survival (OS) (Hazard Ratio [HR] = 0.40, 95%CI 0.32-0.51). Sensitivity analyses for hormone receptor status of breast cancer (HR = 0.41, 95%CI 0.31-0.55) and type of resection performed (HR = 0.45, 95%CI 0.33-0.61) yielded HRs in favor of surgery.

CONCLUSIONS

This meta-analysis concludes that surgery offers superior OS outcomes, compared to non-surgery, in a select group of patients. Future randomized controlled trials and PSM studies are warranted, using this study as a point of reference for similar parameters.

The optimal healthy ranges of thyroid function defined by the risk of cardiovascular disease and mortality: systematic review and individual participant data meta-analysis

BACKGROUND

Reference intervals of thyroid-stimulating hormone (TSH) and free thyroxine (FT4) are statistically defined by the 2·5-97·5th percentiles, without accounting for potential risk of clinical outcomes. We aimed to define the optimal healthy ranges of TSH and FT4 based on the risk of cardiovascular disease and mortality.

METHODS

This systematic review and individual participant data (IPD) meta-analysis identified eligible prospective cohorts through the Thyroid Studies Collaboration, supplemented with a systematic search via Embase, MEDLINE (Ovid), Web of science, the Cochrane Central Register of Controlled Trials, and Google Scholar from Jan 1, 2011, to Feb 12, 2017 with an updated search to Oct 13, 2022 (cohorts found in the second search were not included in the IPD). We included cohorts that collected TSH or FT4, and cardiovascular outcomes or mortality for adults (aged ≥18 years). We excluded cohorts that included solely pregnant women, individuals with overt thyroid diseases, and individuals with cardiovascular disease. We contacted the study investigators of eligible cohorts to provide IPD on demographics, TSH, FT4, thyroid peroxidase antibodies, history of cardiovascular disease and risk factors, medication use, cardiovascular disease events, cardiovascular disease mortality, and all-cause mortality. The primary outcome was a composite outcome including cardiovascular disease events (coronary heart disease, stroke, and heart failure) and all-cause mortality. Secondary outcomes were the separate assessment of cardiovascular disease events, all-cause mortality, and cardiovascular disease mortality. We performed one-step (cohort-stratified Cox models) and two-step (random-effects models) meta-analyses adjusting for age, sex, smoking, systolic blood pressure, diabetes, and total cholesterol. The study was registered with PROSPERO, CRD42017057576.

FINDINGS

We identified 3935 studies, of which 53 cohorts fulfilled the inclusion criteria and 26 cohorts agreed to participate. We included IPD on 134 346 participants with a median age of 59 years (range 18-106) at baseline. There was a J-shaped association of FT4 with the composite outcome and secondary outcomes, with the 20th (median 13·5 pmol/L [IQR 11·2-13·9]) to 40th percentiles (median 14·8 pmol/L [12·3-15·0]) conveying the lowest risk. Compared with the 20-40th percentiles, the age-adjusted and sex-adjusted hazard ratio (HR) for FT4 in the 80-100th percentiles was 1·20 (95% CI 1·11-1·31) for the composite outcome, 1·34 (1·20-1·49) for all-cause mortality, 1·57 (1·31-1·89) for cardiovascular disease mortality, and 1·22 (1·11-1·33) for cardiovascular disease events. In individuals aged 70 years and older, the 10-year absolute risk of composite outcome increased over 5% for women with FT4 greater than the 85th percentile (median 17·6 pmol/L [IQR 15·0-18·3]), and men with FT4 greater than the 75th percentile (16·7 pmol/L [14·0-17·4]). Non-linear associations were identified for TSH, with the 60th (median 1·90 mIU/L [IQR 1·68-2·25]) to 80th percentiles (2·90 mIU/L [2·41-3·32]) associated with the lowest risk of cardiovascular disease and mortality. Compared with the 60-80th percentiles, the age-adjusted and sex-adjusted HR of TSH in the 0-20th percentiles was 1·07 (95% CI 1·02-1·12) for the composite outcome, 1·09 (1·05-1·14) for all-cause mortality, and 1·07 (0·99-1·16) for cardiovascular disease mortality.

INTERPRETATION

There was a J-shaped association of FT4 with cardiovascular disease and mortality. Low concentrations of TSH were associated with a higher risk of all-cause mortality and cardiovascular disease mortality. The 20-40th percentiles of FT4 and the 60-80th percentiles of TSH could represent the optimal healthy ranges of thyroid function based on the risk of cardiovascular disease and mortality, with more than 5% increase of 10-year composite risk identified for FT4 greater than the 85th percentile in women and men older than 70 years. We propose a feasible approach to establish the optimal healthy ranges of thyroid function, allowing for better identification of individuals with a higher risk of thyroid-related outcomes.

FUNDING

None.

Nonlinear effects and effect modification at the participant-level in IPD meta-analysis part 2: methodological guidance is available

OBJECTIVES

To review methodological guidance for nonlinear covariate-outcome associations (NL), and linear effect modification and nonlinear effect modification (LEM and NLEM) at the participant level in individual participant data meta-analyses (IPDMAs) and their power requirements.

STUDY DESIGN AND SETTING

We searched Medline, Embase, Web of Science, Scopus, PsycINFO and the Cochrane Library to identify methodology publications on IPDMA of LEM, NL or NLEM (PROSPERO CRD42019126768).

RESULTS

Through screening 6,466 records we identified 54 potential articles of which 23 full texts were relevant. Nine further relevant publications were published before or after the literature search and were added. Of these 32 references, 21 articles considered LEM, 6 articles NL or NLEM and 6 articles described sample size calculations. A book described all four. Sample size may be calculated through simulation or closed form. Assessments of LEM or NLEM at the participant level need to be based on within-trial information alone. Nonlinearity (NL or NLEM) can be modeled using polynomials or splines to avoid categorization.

CONCLUSION

Detailed methodological guidance on IPDMA of effect modification at participant-level is available. However, methodology papers for sample size and nonlinearity are rarer and may not cover all scenarios. On these aspects, further guidance is needed.

Racial Differences in Mental Stress-Induced Transient Endothelial Dysfunction and Its Association With Cardiovascular Outcomes

OBJECTIVE

This study aimed to investigate differences in transient endothelial dysfunction (TED) with mental stress in Black and non-Black individuals with coronary heart disease (CHD), and their potential impact on cardiovascular outcomes.

METHODS

We examined 812 patients with stable CHD between June 2011 and March 2016 and followed through February 2020 at a university-affiliated hospital network. Flow-mediated vasodilation (FMD) was assessed before and 30 minutes after mental stress. TED was defined as a lower poststress FMD than prestress FMD. We compared prestress FMD, post-stress FMD, and TED between Black and non-Black participants. In both groups, we examined the association of TED with an adjudicated composite end point of cardiovascular death or nonfatal myocardial infarction (first and recurring events) after adjusting for demographic, clinical, and socioeconomic factors.

RESULTS

Prestress FMD was lower in Black than non-Black participants (3.7 [2.8] versus 4.9 [3.8], p < .001) and significantly declined with mental stress in both groups. TED occurred more often in Black (76%) than non-Black patients (67%; multivariable-adjusted odds ratio = 1.6, 95% confidence interval = 1.5-1.7). Over a median (interquartile range) follow-up period of 75 (65-82) months, 142 (18%) patients experienced either cardiovascular death or nonfatal myocardial infarction. Black participants had a 41.9% higher risk of the study outcome than non-Black participants (95% confidence interval = 1.01-1.95). TED with mental stress explained 69% of this excess risk.

CONCLUSIONS

Among CHD patients, Black individuals are more likely than non-Black individuals to develop endothelial dysfunction with mental stress, which in turn explains a substantial portion of their excess risk of adverse events.

Accelerometer-measured physical activity and postmenopausal breast cancer incidence in the Women's Health Accelerometry Collaboration

BACKGROUND

Few studies have examined accelerometer-measured physical activity and incident breast cancer (BC). Thus, this study examined associations between accelerometer-measured vector magnitude counts per 15 seconds (VM/15s) and average daily minutes of light physical activity (LPA), moderate-to-vigorous PA (MVPA), and total PA (TPA) and BC risk among women in the Women's Health Accelerometry Collaboration (WHAC).

METHODS

The WHAC comprised 21,089 postmenopausal women (15,375 from the Women's Health Study [WHS]; 5714 from the Women's Health Initiative Objective Physical Activity and Cardiovascular Health Study [OPACH]). Women wore an ActiGraph GT3X+ on the hip for ≥4 days and were followed for 7.4 average years to identify physician-adjudicated in situ (n = 94) or invasive (n = 546) BCs. Multivariable stratified Cox regression estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for tertiles of physical activity measures in association with incident BC overall and by cohort. Effect measure modification was examined by age, race/ethnicity, and body mass index (BMI).

RESULTS

In covariate-adjusted models, the highest (vs. lowest) tertiles of VM/15s, TPA, LPA, and MVPA were associated with BC HRs of 0.80 (95% CI, 0.64-0.99), 0.84 (95% CI, 0.69-1.02), 0.89 (95% CI, 0.73-1.08), and 0.81 (95% CI, 0.64-1.01), respectively. Further adjustment for BMI or physical function attenuated these associations. Associations were more pronounced among OPACH than WHS women for VM/15s, MVPA, and TPA; younger than older women for MVPA; and women with BMI ≥30 than <30 kg/m2 for LPA.

CONCLUSION

Greater levels of accelerometer-assessed PA were associated with lower BC risk. Associations varied by age and obesity and were not independent of BMI or physical function.

Diagnostic accuracy for hemoperitoneum, influence on prehospital times and time-to-definitive treatment of prehospital FAST: A systematic review and individual participant data meta-analysis

BACKGROUND

Focused assessment sonography for trauma (FAST) performed in the prehospital setting may improve trauma care by influencing treatment decisions and reducing time to definitive care, but its accuracy and benefits remain uncertain. This systematic review evaluated the diagnostic accuracy of prehospital FAST in detecting hemoperitoneum and its effects on prehospital time and time to definitive diagnosis or treatment.

METHODS

We systematically searched PubMed, Embase, and Cochrane library up to November 11th, 2022. Studies investigating prehospital FAST and reporting at least one outcome of interest for this review were considered eligible. The primary outcome was prehospital FAST diagnostic accuracy for hemoperitoneum. A random-effect meta-analysis, including individual patient data, was performed to calculate the pooled outcomes with 95% confidence intervals (CI). Quality of studies was assessed using the QUADAS-2 tool for diagnostic accuracy.

RESULTS

We included 21 studies enrolling 5790 patients. The pooled sensitivity and specificity of prehospital FAST for hemoperitoneum were 0.630 (0.454 - 0.777) and 0.970 (0.957-0.979), respectively. Prehospital FAST was performed in a median of 2.72 (2.12 - 3.31) minutes without increasing prehospital times (pooled median difference of 2.44 min [95% CI: -3.93 - 8.81]) compared to standard management. Prehospital FAST findings changed on-scene trauma care in 12-48% of cases, the choice of admitting hospital in 13-71%, the communication with the receiving hospital in 45-52%, and the transfer management in 52-86%. Patients with a positive prehospital FAST achieved definitive diagnosis or treatment more rapidly (severity-adjusted pooled time ratio = 0.63 [95% CI: 0.41 - 0.95]) compared with patients with a negative or not performed prehospital FAST.

CONCLUSIONS

Prehospital FAST had a low sensitivity but a very high specificity to identify hemoperitoneum and reduced time-to-diagnostics or interventions, without increasing prehospital times, in patients with a high probability of abdominal bleeding. Its effect on mortality is still under-investigated.

Deep Brain Stimulation for Chronic Facial Pain: An Individual Participant Data (IPD) Meta-Analysis

Despite available, advanced pharmacological and behavioral therapies, refractory chronic facial pain of different origins still poses a therapeutic challenge. In circumstances where there is insufficient responsiveness to pharmacological/behavioral therapies, deep brain stimulation should be considered as a potential effective treatment option. We performed an individual participant data (IPD) meta-analysis including searches on PubMed, Embase, and the Cochrane Library (2000–2022). The primary endpoint was the change in pain intensity (visual analogue scale; VAS) at a defined time-point of ≤3 months post-DBS. In addition, correlation and regression analyses were performed to identify predictive markers (age, duration of pain, frequency, amplitude, intensity, contact configuration, and the DBS target). A total of seven trials consisting of 54 screened patients met the inclusion criteria. DBS significantly reduced the pain levels after 3 months without being related to a specific DBS target, age, contact configuration, stimulation intensity, frequency, amplitude, or chronic pain duration. Adverse events were an infection or lead fracture (19%), stimulation-induced side effects (7%), and three deaths (unrelated to DBS—from cancer progression or a second stroke). Although comparable long-term data are lacking, the current published data indicate that DBS (thalamic and PVG/PAG) effectively suppresses facial pain in the short-term. However, the low-quality evidence, reporting bias, and placebo effects must be considered in future randomized-controlled DBS trials for facial pain.

Cardiovascular disease and type 2 diabetes in older adults: a combined protocol for an individual participant data analysis for risk prediction and a network meta-analysis of novel anti-diabetic drugs

Introduction

Older and multimorbid adults with type 2 diabetes (T2D) are at high risk of cardiovascular disease (CVD) and chronic kidney disease (CKD). Estimating risk and preventing CVD is a challenge in this population notably because it is underrepresented in clinical trials. Our study aims to (1) assess if T2D and haemoglobin A1c (HbA1c) are associated with the risk of CVD events and mortality in older adults, (2) develop a risk score for CVD events and mortality for older adults with T2D, (3) evaluate the comparative efficacy and safety of novel antidiabetics.

Methods and analysis

For Aim 1, we will analyse individual participant data on individuals aged ≥65 years from five cohort studies: the Optimising Therapy to Prevent Avoidable Hospital Admissions in Multimorbid Older People study; the Cohorte Lausannoise study; the Health, Aging and Body Composition study; the Health and Retirement Study; and the Survey of Health, Ageing and Retirement in Europe. We will fit flexible parametric survival models (FPSM) to assess the association of T2D and HbA1c with CVD events and mortality. For Aim 2, we will use data on individuals aged ≥65 years with T2D from the same cohorts to develop risk prediction models for CVD events and mortality using FPSM. We will assess model performance, perform internal-external cross validation, and derive a point-based risk score. For Aim 3, we will systematically search randomized controlled trials of novel antidiabetics. Network meta-analysis will be used to determine comparative efficacy in terms of CVD, CKD, and retinopathy outcomes, and safety of these drugs. Confidence in results will be judged using the CINeMA tool.

Ethics and dissemination

Aims 1 and 2 were approved by the local ethics committee (Kantonale Ethikkommission Bern); no approval is required for Aim 3. Results will be published in peer-reviewed journals and presented in scientific conferences.

Order of patient entry and outcomes in phase II clinical trials: A meta-analysis of individual patient data

BACKGROUND

Prior meta-analysis of stem-cell transplantation trials for renal-cell carcinoma observed that clinical outcomes vary by subjects' order of entry, specifically their quartile of accrual. We test this hypothesis using meta-analysis of individual patient data from diverse Phase II trials conducted by an oncology consortium.

METHODS

Eligible were all Phase II trials in hematologic or solid tumors opened and closed by California Cancer Consortium during 2005-2020. Excluded were trials closed in first quartile or currently embargoed pending publication and subjects ineligible per protocol or untreated on study. The primary risk factor was entry by quartile of planned sample size. As a cross-protocol endpoint, primary outcome was time to discontinuation of intervention. One-stage meta-analysis used a shared frailty model with trial as random effect. As covariates, stepwise selection retained tumor type, obesity, their interaction, calendar year, entry at least 3 years post-diagnosis, and performance status but rejected age, sex, randomized design, and class of drug.

RESULTS

Twenty trials (including 8 terminated early, 2 not published) included n = 923 subjects. Most (90.6%) subjects discontinued intervention, usually for disease progression or toxicity. Independently of covariates, risk of discontinuation increased (p < 0.0001) with each quartile of entry (Hazards Ratio 1.13, 95% CI 1.06-1.22), culminating at Quartile 4 (HR 1.46, 1.36-1.57). The 95% prediction interval for the Hazards Ratio in future trials was (1.04-1.24). Progression-free survival similarly worsened by quartile of entry.

CONCLUSION

In Phase II trials, clinical outcome worsens with quartile of entry. This finding merits independent replication, and the cause of this phenomenon merits investigation.

Early selexipag initiation and long-term outcomes: insights from randomised controlled trials in pulmonary arterial hypertension

Further understanding of when to initiate therapies in pulmonary arterial hypertension (PAH) is important to improve long-term outcomes. Post hoc analyses of GRIPHON (NCT01106014) and exploratory analyses of TRITON (NCT02558231) suggested benefit of early selexipag initiation on long-term outcomes, despite no additional benefit versus initial double combination on haemodynamic and functional parameters in TRITON. Post hoc analyses investigated the effect of early selexipag initiation on disease progression and survival in a large, pooled PAH cohort. Data from newly diagnosed (≤6 months) PAH patients from GRIPHON and TRITON were pooled. Patients on active therapy with selexipag (pooled selexipag group) were compared with those on control therapy with placebo (pooled control group). Disease progression end-points were defined as per the individual studies. Hazard ratios (HR) and 95% CI for time to first disease progression event up to end of double-blind treatment (selexipag/placebo) +7 days and time to all-cause death up to end of study were estimated using Cox regression models. The pooled dataset comprised 649 patients, with 44% on double background therapy. Selexipag reduced the risk of disease progression by 52% versus control (HR: 0.48; 95% CI: 0.35-0.66). HR for risk of all-cause death was 0.70 (95% CI: 0.46-1.10) for the pooled selexipag versus control group. Sensitivity analyses accounting for the impact of PAH background therapy showed consistent results, confirming the appropriateness of data pooling. These post hoc, pooled analyses build on previous insights, further supporting selexipag use within 6 months of diagnosis, including as part of triple therapy, to delay disease progression.

Radiotherapy Fraction in Limited-Stage Small Cell Lung Cancer in the Modern Era: A Systematic Review and Meta-Analysis of 8006 Reconstructed Individual Patient Data

The optimal thoracic radiotherapy (TRT) dose and fractionation for limited-stage small cell lung cancer (LS-SCLC) using modern techniques remain unclear. We conducted systematic review and meta-analyses of the efficacy and safety differences between definitive hypofractionated TRT (HypoTRT), conventional TRT (ConvTRT) and hyperfractionated TRT (HyperTRT), especially in the modern era. Eligible randomized controlled trials (RCTs), real-world cohorts, and single-arm trials published between 1990 and 2021 were identified. Two meta-analyses of overall survival (OS) were conducted: (i) a random-effects meta-analysis based on reconstructed individual-patient data (IPD) of all studies; and (ii) a Bayesian network meta-analysis based on study-level aggregated data (AD) of RCTs. The incidences of severe radiation-related toxicities were compared using the random-effects meta-regression model. Overall, 53 of the 30,031 publications met the inclusion criteria, and a total of 8006 IPD were reconstructed. After adjusting for key treatment variables and stratification by study type, there were no significant differences in the OS rates between the altered fractionation regimens (HypoTRT vs. HyperTRT, aHR [adjusted HR] = 1.05, 95% CI 0.93-1.19; ConvTRT vs. HyperTRT, aHR = 1.00, 95% CI 0·90-1.11; HypoTRT vs. ConvTRT, aHR = 1.05, 95% CI 0.91-1.20). In the modern era, the survival outcomes of all three schedules, while remaining comparable, have improved significantly. Results of the AD-based network meta-analysis were consistent with those of IPD analysis, and HypoTRT was ranked as the best regimen (SUCRA = 81%). There were no significant differences in toxicities between groups when using modern radiation techniques. In the modern era, no significant differences in OS or severe radiation-related toxicities were observed between altered schedules in LS-SCLC. HypoTRT may be associated with moderate and non-significant OS improvements, which should be further confirmed in prospective randomized phase III trials.

Individual participant data meta-analysis of trials comparing frozen versus fresh embryo transfer strategy (INFORM): a protocol

INTRODUCTION

Existing randomised controlled trials (RCTs) comparing a freeze-all embryo transfer strategy and a fresh embryo transfer strategy have shown conflicting results. A freeze-all or a fresh transfer policy may be preferable for some couples undergoing in-vitro fertilisation (IVF), but it is unclear which couples would benefit most from each policy, how and under which protocols. Therefore, we plan a systematic review and individual participant data meta-analysis of RCTs comparing a freeze-all and a fresh transfer policy.

METHODS AND ANALYSIS

We will search electronic databases (Medline, Embase, PsycINFO and CENTRAL) and trial registries (ClinicalTrials.gov and the International Clinical Trials Registry Platform) from their inception to present to identify eligible RCTs. We will also check reference lists of relevant papers. The search was performed on 23 September 2020 and will be updated. We will include RCTs comparing a freeze-all embryo transfer strategy and a fresh embryo transfer strategy in couples undergoing IVF. The primary outcome will be live birth resulting from the first embryo transfer. All outcomes listed in the core outcome set for infertility research will be reported. We will invite the lead investigators of eligible trials to join the Individual participant data meta-analysis of trials comparing frozen versus fresh embryo transfer strategy (INFORM) collaboration and share the deidentified individual participant data (IPD) of their trials. We will harmonise the IPD and perform a two-stage meta-analysis and examine treatment-covariate interactions for important baseline characteristics.

ETHICS AND DISSEMINATION

The study ethics have been granted by the Monash University Human Research Ethics Committee (Project ID: 30391). The findings will be disseminated via presentations at international conferences and publication in peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42021296566.

Meta-Analysis of Percutaneous Coronary Intervention Versus Coronary Artery Bypass Grafting for Left Main Narrowing

Randomized controlled trials (RCTs) comparing percutaneous coronary intervention (PCI) with drug-eluting stents and coronary artery bypass grafting (CABG) for patients with left main coronary artery disease (LMCAD) have reported conflicting results. We performed a systematic review up to May 23, 2021, and 1-stage reconstructed individual patient data meta-analysis (IPDMA) to compare outcomes between both groups. The primary outcome was 10-year all-cause mortality. Secondary outcomes included myocardial infarction (MI), stroke, and unplanned revascularization at 5 years. We performed individual patient data meta-analysis using published Kaplan-Meier curves to provide individual data points in coordinates and numbers at risk were used to increase the calibration accuracy of the reconstructed data. Shared frailty model or, when proportionality assumptions were not met, a restricted mean survival time model were fitted to compare outcomes between treatment groups. Of 583 articles retrieved, 5 RCTs were included. A total of 4,595 patients from these 5 RCTs were randomly assigned to PCI (n = 2,297) or CABG (n = 2,298). The cumulative 10-year all-cause mortality after PCI and CABG was 12.0% versus 10.6%, respectively (hazard ratio [HR] 1.093, 95% confidence interval [CI] 0.925 to 1.292; p = 0.296). PCI conferred similar time-to-MI (restricted mean survival time ratio 1.006, 95% CI 0.992 to 1.021, p=0.391) and stroke (restricted mean survival time ratio 1.005, 95% CI 0.998 to 1.013, p = 0.133) at 5 years. Unplanned revascularization was more frequent after PCI than CABG (HR 1.807, 95% CI 1.524 to 2.144, p <0.001) at 5 years. This meta-analysis using reconstructed participant-level time-to-event data showed no statistically significant difference in cumulative 10-year all-cause mortality between PCI versus CABG in the treatment of LMCAD.

Risk of Peritoneal Carcinomatosis After Risk-Reducing Salpingo-Oophorectomy: A Systematic Review and Individual Patient Data Meta-Analysis

PURPOSE

After risk-reducing salpingo-oophorectomy (RRSO), BRCA1/2 pathogenic variant (PV) carriers have a residual risk to develop peritoneal carcinomatosis (PC). The etiology of PC is not yet clarified, but may be related to serous tubal intraepithelial carcinoma (STIC), the postulated origin for high-grade serous cancer. In this systematic review and individual patient data meta-analysis, we investigate the risk of PC in women with and without STIC at RRSO.

METHODS

Unpublished data from three centers were supplemented by studies identified in a systematic review of EMBASE, MEDLINE, and the Cochrane library describing women with a BRCA-PV with and without STIC at RRSO until September 2020. Primary outcome was the hazard ratio for the risk of PC between BRCA-PV carriers with and without STIC at RRSO, and the corresponding 5- and 10-year risks. Primary analysis was based on a one-stage Cox proportional-hazards regression with a frailty term for study.

RESULTS

From 17 studies, individual patient data were available for 3,121 women, of whom 115 had a STIC at RRSO. The estimated hazard ratio to develop PC during follow-up in women with STIC was 33.9 (95% CI, 15.6 to 73.9), P < .001) compared with women without STIC. For women with STIC, the five- and ten-year risks to develop PC were 10.5% (95% CI, 6.2 to 17.2) and 27.5% (95% CI, 15.6 to 43.9), respectively, whereas the corresponding risks were 0.3% (95% CI, 0.2 to 0.6) and 0.9% (95% CI, 0.6 to 1.4) for women without STIC at RRSO.

CONCLUSION

BRCA-PV carriers with STIC at RRSO have a strongly increased risk to develop PC which increases over time, although current data are limited by small numbers of events.

Risk of Hepatocellular Carcinoma With Tenofovir vs Entecavir Treatment for Chronic Hepatitis B Virus: A Reconstructed Individual Patient Data Meta-analysis

IMPORTANCE

Conventional meta-analyses with aggregated study-level data have yielded conflicting results for the comparative effectiveness of tenofovir disoproxil fumarate vs entecavir in reducing hepatocellular carcinoma (HCC) risk among patients with chronic hepatitis B virus. Within-study heterogeneity, between-study heterogeneity, and the inability of conventional meta-analyses to capture time-to-event data were associated with these results.

OBJECTIVE

To perform a reconstructed individual patient data meta-analysis of high-quality propensity score-matched studies to provide robust estimates for comparative HCC risk between groups receiving tenofovir or entecavir.

DATA SOURCES

Medline and Embase databases were searched from inception to October 6, 2021.

STUDY SELECTION

The initial search yielded 3435 articles. Fourteen studies that used propensity score matching to balance baseline characteristics were included in the final analysis.

DATA EXTRACTION AND SYNTHESIS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses guideline was followed. Individual patient data were reconstructed from Kaplan-Meier curves. Risk of HCC was evaluated using random-effects hazard ratios (HRs) via a shared-frailty model and a Cox proportional hazards model stratified by study group. Restricted mean survival time (RMST) analysis was conducted to account for varying estimated treatment effect across time.

MAIN OUTCOMES AND MEASURES

The comparative risk of HCC with tenofovir vs entecavir treatment.

RESULTS

From analysis of 14 studes with 24 269 patients (10 534 receiving tenofovir and 13 735 receiving entecavir; mean age, 49.86 [95% CI, 48.35-51.36] years; 65.05% [95% CI, 58.60%-71.00%] men), tenofovir was associated with decreased HCC incidence compared with entecavir (stratified Cox HR, 0.85 [95% CI, 0.76-0.94] at 5 years; P = .002). However, there was no significant difference in subanalysis of clinical cohort studies (stratified Cox HR, 0.92 [95% CI, 0.80-1.06] at 5 years; P = .24). Among administrative database studies, proportionality was violated, and HRs could not be obtained via Cox proporational hazards-based models. The mean time to HCC development in RMST analysis was 2.8 (95% CI, 1.8-3.7) weeks longer (P < .001) for tenofovir vs entecavir at 5 years. The RMST analyses for other subgroups revealed either insignificant or minimal differences (<3 weeks) in the mean time to HCC at 5 years.

CONCLUSIONS AND RELEVANCE

In this meta-analysis, there was no clinically meaningful difference in the risk of HCC between patients who received entecavir and patients who received tenofovir. There was no difference between tenofovir and entecavir among clinical cohort studies, whereas the mean time to HCC development was less than 3 weeks longer for patients who received tenofovir vs those who received entecavir at year 5 among administrative database studies. The choice between tenofovir or entecavir should be decided based on patient convenience and tolerability.

Challenges of modelling approaches for network meta-analysis of time-to-event outcomes in the presence of non-proportional hazards to aid decision making: Application to a melanoma network

BACKGROUND

Synthesis of clinical effectiveness from multiple trials is a well-established component of decision-making. Time-to-event outcomes are often synthesised using the Cox proportional hazards model assuming a constant hazard ratio over time. However, with an increasing proportion of trials reporting treatment effects where hazard ratios vary over time and with differing lengths of follow-up across trials, alternative synthesis methods are needed.

OBJECTIVES

To compare and contrast five modelling approaches for synthesis of time-to-event outcomes and provide guidance on key considerations for choosing between the modelling approaches.

METHODS

The Cox proportional hazards model and five other methods of estimating treatment effects from time-to-event outcomes, which relax the proportional hazards assumption, were applied to a network of melanoma trials reporting overall survival: restricted mean survival time, generalised gamma, piecewise exponential, fractional polynomial and Royston-Parmar models.

RESULTS

All models fitted the melanoma network acceptably well. However, there were important differences in extrapolations of the survival curve and interpretability of the modelling constraints demonstrating the potential for different conclusions from different modelling approaches.

CONCLUSION

The restricted mean survival time, generalised gamma, piecewise exponential, fractional polynomial and Royston-Parmar models can accommodate non-proportional hazards and differing lengths of trial follow-up within a network meta-analysis of time-to-event outcomes. We recommend that model choice is informed using available and relevant prior knowledge, model transparency, graphically comparing survival curves alongside observed data to aid consideration of the reliability of the survival estimates, and consideration of how the treatment effect estimates can be incorporated within a decision model.

Autobiographical memory style and clinical outcomes following mindfulness-based cognitive therapy (MBCT): An individual patient data meta-analysis

The ability to retrieve specific, single-incident autobiographical memories has been consistently posited as a predictor of recurrent depression. Elucidating the role of autobiographical memory specificity in patient-response to depressive treatments may improve treatment efficacy and facilitate use of science-driven interventions. We used recent methodological advances in individual patient data meta-analysis to determine a) whether memory specificity is improved following mindfulness-based cognitive therapy (MBCT), relative to control interventions, and b) whether pre-treatment memory specificity moderates treatment response. All bar one study evaluated MBCT for relapse prevention for depression. Our initial analysis therefore focussed on MBCT datasets only(n = 708), then were repeated including the additional dataset(n = 880). Memory specificity did not significantly differ from baseline to post-treatment for either MBCT and Control interventions. There was no evidence that baseline memory specificity predicted treatment response in terms of symptom-levels, or risk of relapse. Findings raise important questions regarding the role of memory specificity in depressive treatments.

Development and validation of clinical prediction models for breast cancer incidence and mortality: a protocol for a dual cohort study

INTRODUCTION

Breast cancer is the most common cancer and the leading cause of cancer-related death in women worldwide. Risk prediction models may be useful to guide risk-reducing interventions (such as pharmacological agents) in women at increased risk or inform screening strategies for early detection methods such as screening.

METHODS AND ANALYSIS

The study will use data for women aged 20-90 years between 2000 and 2020 from QResearch linked at the individual level to hospital episodes, cancer registry and death registry data. It will evaluate a set of modelling approaches to predict the risk of developing breast cancer within the next 10 years, the 'combined' risk of developing a breast cancer and then dying from it within 10 years, and the risk of breast cancer mortality within 10 years of diagnosis. Cox proportional hazards, competing risks, random survival forest, deep learning and XGBoost models will be explored. Models will be developed on the entire dataset, with 'apparent' performance reported, and internal-external cross-validation used to assess performance and geographical and temporal transportability (two 10-year time periods). Random effects meta-analysis will pool discrimination and calibration metric estimates from individual geographical units obtained from internal-external cross-validation. We will then externally validate the models in an independent dataset. Evaluation of performance heterogeneity will be conducted throughout, such as exploring performance across ethnic groups.

ETHICS AND DISSEMINATION

Ethics approval was granted by the QResearch scientific committee (reference number REC 18/EM/0400: OX129). The results will be written up for submission to peer-reviewed journals.

Coronary Artery Bypass Grafting Versus Percutaneous Coronary Intervention for Multivessel Coronary Artery Disease: A One-Stage Meta-Analysis

Background and Aims

Data are emerging on 10-year mortality comparing coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) with stenting for multivessel disease (MVD) without left main (LM) involvement. We conducted an updated two-stage meta-analysis using reconstructed individual patient data to compare long-term mortality between CABG and PCI for patients with MVD without significant LM coronary disease.

Methods

Medline and Embase databases were searched for articles comparing CABG with PCI for MVD. A two-stage meta-analysis was conducted using reconstructed patient level survival data for all-cause mortality with subgroups by SYNTAX score. The shared-frailty and stratified Cox models were fitted to compare survival endpoints.

Results

We screened 1,496 studies and included six randomized controlled trials with 7,181 patients. PCI was associated with greater 10-year all-cause mortality risk (HR: 1.282, CI: 1.118–1.469, p < 0.001) compared with CABG. In patients with low SYNTAX score, 10-year all-cause mortality after PCI was comparable to CABG (HR: 1.102, 0.822–1.479, p = 0.516). However, in patients with moderate to high SYNTAX score, 10-year all-cause mortality was significantly higher after PCI compared with CABG (HR: 1.444, 1.122–1.858, p < 0.001; HR: 1.856, 1.380–2.497, p < 0.001, respectively).

Conclusion

This updated reconstructed individual patient-data meta-analysis revealed a sustained lower cumulative all-cause mortality of CABG over PCI for multivessel disease without LM involvement.

Weekly versus tri-weekly paclitaxel with carboplatin for first-line treatment in women with epithelial ovarian cancer

BACKGROUND

Epithelial ovarian cancer is the sixth most common cancer worldwide: 295,414 new cases were diagnosed in 2018, with 184,799 deaths. The lack of an effective screening strategy has led to the majority of women being diagnosed at an advanced stage. For these women, intravenous carboplatin combined with paclitaxel for six cycles is widely accepted as the standard first-line treatment for epithelial ovarian cancer, in combination with debulking surgery. However, there is conflicting evidence regarding the optimal dosing schedule of paclitaxel when combined with carboplatin in this setting.

OBJECTIVES

To compare the efficacy and tolerability of intravenous weekly paclitaxel with that of tri-weekly paclitaxel, in combination with intravenous carboplatin, as first-line treatment for epithelial ovarian cancer (defined as epithelial ovarian, primary peritoneal and fallopian tube cancer).

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase databases for relevant studies up to 15 November 2021, using keywords and MeSH terms. We additionally handsearched conference libraries, online clinical trial databases and screened through lists of retrieved references.

SELECTION CRITERIA

We Included randomised controlled trials (RCTs) comparing weekly paclitaxel in combination with carboplatin versus tri-weekly paclitaxel in combination with carboplatin, for treatment of newly-diagnosed epithelial ovarian cancer.

DATA COLLECTION AND ANALYSIS

We used the hazard ratio (HR) to estimate the primary efficacy outcomes progression-free (PFS) and overall survival (OS). We used the risk ratio (RR) to estimate the primary toxicity outcome of severe neutropenia and secondary outcomes of quality of life (QoL) and treatment-related adverse events. Two review authors independently selected studies, extracted data, and assessed risk of bias, using standard Cochrane methodological procedures. We included individual participant data (IPD) from one of the included studies, ICON-8, provided by the study team. We analysed data using a random-effects model in Review Manager 5.4 software. Additionally, we reconstructed IPD for PFS and OS data from published Kaplan-Meier curves from all studies and subsequently pooled these to analyse the two primary efficacy outcomes.

MAIN RESULTS

From 2469 records, we identified four eligible RCTs with data for 3699 participants. All eligible studies were included in the main meta-analysis and reported on PFS and OS. There was likely a slight improvement in PFS when paclitaxel was dosed weekly compared to tri-weekly (HR 0.89, 95% confidence interval (CI) 0.81 to 0.98; 4 studies, 3699 participants; moderate-certainty evidence). We found little to no improvement in OS when paclitaxel was dosed weekly compared to tri-weekly (HR 0.92, 95% CI 0.79 to 1.06; 4 studies, 3699 participants; high-certainty evidence). There was likely little to no difference in high-grade (grade 3 or 4) neutropenia when paclitaxel was dosed weekly compared to tri-weekly (RR 1.11, 95% CI 0.86 to 1.43; 4 studies, 3639 participants; moderate-certainty evidence). However, weekly paclitaxel increased high-grade (grade 3 or 4) anaemia when compared to tri-weekly dosing (RR 1.57, 95% CI 1.12 to 2.20; 4 studies, 3639 participants; high-certainty evidence). There may be little to no difference in high-grade neuropathy when paclitaxel was dosed weekly compared to tri-weekly (RR 1.12, 95% CI 0.64 to 1.94; 4 studies, 3639 participants; low-certainty evidence). The overall risk of detection bias and performance bias was low for OS, but was unclear for other outcomes, as treatments were not blinded. The risk of bias in other domains was low or unclear. We note that OS data were immature for three of the included studies (GOG-0262, ICON-8 and MITO-7).

AUTHORS' CONCLUSIONS

Weekly paclitaxel combined with carboplatin for first-line treatment of epithelial ovarian cancer likely improves PFS slightly (moderate-certainty evidence) but not OS (high-certainty evidence), compared to tri-weekly paclitaxel combined with carboplatin. However, this was associated with increased risk for high-grade anaemia, treatment discontinuation, dose delays and dose omissions (high- to low-certainty evidence). Our findings may not apply to women receiving bevacizumab in first-line therapy, those receiving treatment in the neo-adjuvant setting, or those with rare subtypes of clear cell or mucinous ovarian cancer.

Neoadjuvant Treatment with HER2-Targeted Therapies in HER2-Positive Breast Cancer: A Systematic Review and Network Meta-Analysis

Simple Summary

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer causes more aggressive progression of disease and poorer outcomes for patients. HER2-targeted medicines used as neoadjuvant systemic therapy could improve clinical outcomes in early-stage or locally advanced breast cancer patients. The purpose of this systematic review and network meta-analysis was to identify the neoadjuvant anti-HER2 therapy with the best balance between efficacy and safety. We found that trastuzumab emtansine + pertuzumab + chemotherapy had a high pathologic complete response with a low risk of adverse events compared to other neoadjuvant anti-HER2 regimens, while the pertuzumab + trastuzumab + chemotherapy regimen showed the highest disease-free survival. However, further trial data on neoadjuvant regimens with trastuzumab emtansine are needed to confirm these findings.

Abstract

This systematic review aimed to identify neoadjuvant anti-human epidermal growth factor receptor 2 (HER2) therapies with the best balance between efficacy and safety. Methods: A network meta-analysis was applied to estimate the risk ratios along with 95% confidence intervals (CIs) for pathological complete response (pCR) and serious adverse events (SAE). A mixed-effect parametric survival analysis was conducted to assess the disease-free survival (DFS) between treatments. Results: Twenty-one RCTs with eleven regimens of neoadjuvant anti-HER2 therapy (i.e., trastuzumab + chemotherapy (TC), lapatinib + chemotherapy (LC), pertuzumab + chemotherapy (PC), pertuzumab + trastuzumab (PT), trastuzumab emtansine + pertuzumab (T-DM1P), pertuzumab + trastuzumab + chemotherapy (PTC), lapatinib + trastuzumab + chemotherapy (LTC), trastuzumab emtansine + lapatinib + chemotherapy (T-DM1LC), trastuzumab emtansine + pertuzumab + chemotherapy(T-DM1PC), PTC followed by T-DM1P (PTC_T-DM1P), and trastuzumab emtansine (T-DM1)) and chemotherapy alone were included. When compared to TC, only PTC had a significantly higher DFS with a hazard ratio (95% CI) of 0.54 (0.32–0.91). The surface under the cumulative ranking curve (SUCRA) suggested that T-DM1LC (91.9%) was ranked first in achieving pCR, followed by the PTC_T-DM1P (90.5%), PTC (74.8%), and T-DM1PC (73.5%) regimens. For SAEs, LTC, LC, and T-DM1LC presented with the highest risks (SUCRA = 10.7%, 16.8%, and 20.8%), while PT (99.2%), T-DM1P (88%), and T-DM1 (83.9%) were the safest regimens. The T-DM1PC (73.5% vs. 71.6%), T-DM1 (70.5% vs. 83.9%), and PTC_T-DM1P (90.5% vs. 47.3%) regimens offered the optimal balance between pCR and SAE. Conclusions: The T-DM1PC, T-DM1, and PTC_T-DM1P regimens had the optimal balance between efficacy and safety, while DFS was highest for the PTC regimen. However, these results were based on a small number of studies, and additional RCTs assessing the efficacy of regimens with T-DM1 are still needed to confirm these findings.

Systematic Review Reveals Lack of Causal Methodology Applied to Pooled Longitudinal Observational Infectious Disease Studies

OBJECTIVES

Among ID studies seeking to make causal inferences and pooling individual-level longitudinal data from multiple infectious disease cohorts, we sought to assess what methods are being used, how those methods are being reported, and whether these factors have changed over time.

STUDY DESIGN AND SETTING

Systematic review of longitudinal observational infectious disease studies pooling individual-level patient data from 2+ studies published in English in 2009. 2014, or 2019. This systematic review protocol is registered with PROSPERO (CRD42020204104).

RESULTS

Our search yielded 1,462 unique articles. Of these, 16 were included in the final review. Our analysis showed a lack of causal inference methods and of clear reporting on methods and the required assumptions.

CONCLUSION

There are many approaches to causal inference which may help facilitate accurate inference in the presence of unmeasured and time-varying confounding. In observational ID studies leveraging pooled, longitudinal IPD, the absence of these causal inference methods and gaps in the reporting of key methodological considerations suggests there is ample opportunity to enhance the rigor and reporting of research in this field. Interdisciplinary collaborations between substantive and methodological experts would strengthen future work.

Editor's Choice - Risk of Major Amputation Following Application of Paclitaxel Coated Balloons in the Lower Limb Arteries: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

OBJECTIVE

There have been concerns about the long term safety of paclitaxel coated devices in the lower limbs. A formal systematic review and meta-analysis of randomised controlled trials (RCTs) was performed to examine the long term risk of major amputation using paclitaxel coated balloons in peripheral arterial disease (PAD).

METHOD

This systematic review was registered with PROSPERO (ID 227761). A broad bibliographic search was performed for RCTs investigating paclitaxel coated balloons in the peripheral arteries (femoropopliteal and infrapopliteal) for treatment of intermittent claudication or critical limb ischaemia (CLI). The literature search was last updated on 20 February 2021 without any restrictions on publication language, date, or status. Major amputations were analysed with time to event methods employing one and two stage models. Sensitivity and subgroup analyses, combinatorial meta-analysis, and a multivariable dose response meta-analysis to examine presence of a biological gradient were also performed.

RESULTS

In all, 21 RCTs with 3 760 lower limbs were analysed (52% intermittent claudication and 48% CLI; median follow up two years). There were 87 major amputations of 2 216 limbs in the paclitaxel arms (4.0% crude risk) compared with 41 major amputations in 1 544 limbs in the control arms (2.7% crude risk). The risk of major amputation was significantly higher for paclitaxel coated balloons with a hazard ratio (HR) of 1.66 (95% CI 1.14 - 2.42; p = .008, one stage stratified Cox model). The prediction interval was 95% CI 1.10 - 2.46 (two stage model). The observed amputation risk was consistent for both femoropopliteal (p = .055) and infrapopliteal (p = .055) vessels. Number needed to harm was 35 for CLI. There was good evidence of a significant non-linear dose response relationship with accelerated risk per cumulative paclitaxel dose (chi square model p = .007). There was no evidence of publication bias (p = .80) and no significant statistical heterogeneity between studies (I2 = 0%, p = .77). Results were stable across sensitivity analyses (different models and subgroups based on anatomy and clinical indication and excluding unpublished trials). There were no influential single trials. Level of certainty in evidence was downrated from high to moderate because of sparse events in some studies.

CONCLUSION

There appears to be heightened risk of major amputation after use of paclitaxel coated balloons in the peripheral arteries. Further investigations are warranted urgently.

DNA-thioguanine concentration and relapse risk in children and young adults with acute lymphoblastic leukemia: an IPD meta-analysis

Methotrexate/6-mercaptopurine maintenance therapy improves acute lymphoblastic leukemia (ALL) outcome. Cytotoxicity is mediated by DNA incorporation of thioguanine nucleotides (DNA-TG). We investigated the association of DNA-TG to relapse risk in 1 910 children and young adults with non-high risk ALL. In a cohort-stratified Cox regression analysis adjusted for sex, age, and white cell count at diagnosis, the relapse-specific hazard ratio (HRa) per 100 fmol/μg increase in weighted mean DNA-TG (wmDNA-TG) was 0.87 (95% CI 0.78-0.97; p = 0.013) in the 839 patients who were minimal residual disease (MRD) positive at end of induction therapy (EOI), whereas this was not the case in EOI MRD-negative patients (p = 0.76). Validation analysis excluding the previously published Nordic NOPHO ALL2008 pediatric cohort yielded a HRa of 0.92 (95% CI 0.82-1.03; p = 0.15) per 100 fmol/μg increase in wmDNA-TG in EOI MRD-positive patients. If also excluding the United Kingdom cohort, in which samples were taken non-randomly in selected patients, the HRa for the EOI MRD-positive patients was 0.82 (95% CI 0.68-0.99; p = 0.044) per 100 fmol/μg increase in wmDNA-TG. The importance of DNA-TG as a biomarker for maintenance therapy intensity calls for novel strategies to increase DNA-TG, although its clinical value may vary by protocol backbone.

Cohort profile: the Women's Health Accelerometry Collaboration

PURPOSE

This paper describes the Women's Health Accelerometry Collaboration, a consortium of two prospective cohort studies of women age 62 years or older, harmonised to explore the association of accelerometer-assessed physical activity and sedentary behaviour with cancer incidence and mortality.

PARTICIPANTS

A total of 23 443 women (age mean 73.4, SD 6.8) living in the USA and participating in an observational study were included; 17 061 from the Women's Health Study (WHS) and 6382 from the Women's Health Initiative Objective Physical Activity and Cardiovascular Health (WHI/OPACH) Study.

FINDINGS TO DATE

Accelerometry, cancer outcomes and covariate harmonisation was conducted to align the two cohort studies. Physical activity and sedentary behaviour were measured using similar procedures with an ActiGraph GT3X+ accelerometer, worn at the hip for 1 week, during 2011-2014 for WHS and 2012-2014 for WHI/OPACH. Cancer outcomes were ascertained via ongoing surveillance using physician adjudicated cancer diagnosis. Relevant covariates were measured using questionnaire or physical assessments. Among 23 443 women who wore the accelerometer for at least 10 hours on a single day, 22 868 women wore the accelerometer at least 10 hours/day on ≥4 of 7 days. The analytical sample (n=22 852) averaged 4976 (SD 2669) steps/day and engaged in an average of 80.8 (SD 46.5) min/day of moderate-to-vigorous, 105.5 (SD 33.3) min/day of light high and 182.1 (SD 46.1) min/day of light low physical activity. A mean of 8.7 (SD 1.7) hours/day were spent in sedentary behaviour. Overall, 11.8% of the cohort had a cancer diagnosis (other than non-melanoma skin cancer) at the time of accelerometry measurement. During an average of 5.9 (SD 1.6) years of follow-up, 1378 cancer events among which 414 were fatal have occurred.

FUTURE PLANS

Using the harmonised cohort, we will access ongoing cancer surveillance to quantify the associations of physical activity and sedentary behaviour with cancer incidence and mortality.

Laparoscopic versus open resection for rectal cancer: An individual patient data meta analysis of randomized controlled trials

BACKGROUND AND AIMS

The role of laparoscopic rectal cancer resection remains controversial. Thus, we aimed to conduct a one-stage meta-analysis with reconstructed patient-level data using randomized trial data to compare long-term oncologic efficacy of laparoscopic and open surgical resection for rectal cancer.

METHODS

Medline, EMBASE and Scopus were searched for articles comparing laparoscopic with open surgery for rectal cancer. Primary outcome was disease free survival (DFS) while secondary outcome was overall survival (OS). One-stage meta-analysis was conducted using patient-level survival data reconstructed from Kaplan-Meier curves with Web Plot Digitizer. Shared-frailty and stratified Cox models were fitted to compare survival endpoints.

RESULTS

Seven randomized trials involving 1767 laparoscopic and 1293 open resections for rectal cancer were included. There were no significant differences between both groups for DFS and OS with respective hazard ratio estimates of 0.91 (95% CI: 0.78-1.06, p = 0.241) and 0.86 (95% CI:0.73-1.02, p = 0.090). Sensitivity analysis for non-metastatic patients and patients with mid and lower rectal cancer showed no significant differences in OS and DFS between both surgical approaches. In the laparoscopic arm, improved DFS was noted for stage II (HR: 0.73, 95% CI:0.54-0.98, p = 0.036) and stage III rectal cancers (HR: 0.74, 95% CI:0.55-0.99, p = 0.041).

CONCLUSIONS

This meta-analysis concludes that laparoscopic rectal cancer resection does not compromise long-term oncologic outcomes compared with open surgery with potential survival benefits for a minimal access approach in patients with stage II and III rectal cancer.

Association of Mental Stress-Induced Myocardial Ischemia With Cardiovascular Events in Patients With Coronary Heart Disease

IMPORTANCE

Mental stress-induced myocardial ischemia is a recognized phenomenon in patients with coronary heart disease (CHD), but its clinical significance in the contemporary clinical era has not been investigated.

OBJECTIVE

To compare the association of mental stress-induced or conventional stress-induced ischemia with adverse cardiovascular events in patients with CHD.

DESIGN, SETTING, AND PARTICIPANTS

Pooled analysis of 2 prospective cohort studies of patients with stable CHD from a university-based hospital network in Atlanta, Georgia: the Mental Stress Ischemia Prognosis Study (MIPS) and the Myocardial Infarction and Mental Stress Study 2 (MIMS2). Participants were enrolled between June 2011 and March 2016 (last follow-up, February 2020).

EXPOSURES

Provocation of myocardial ischemia with a standardized mental stress test (public speaking task) and with a conventional (exercise or pharmacological) stress test, using single-photon emission computed tomography.

MAIN OUTCOMES AND MEASURES

The primary outcome was a composite of cardiovascular death or first or recurrent nonfatal myocardial infarction. The secondary end point additionally included hospitalizations for heart failure.

RESULTS

Of the 918 patients in the total sample pool (mean age, 60 years; 34% women), 618 participated in MIPS and 300 in MIMS2. Of those, 147 patients (16%) had mental stress-induced ischemia, 281 (31%) conventional stress ischemia, and 96 (10%) had both. Over a 5-year median follow-up, the primary end point occurred in 156 participants. The pooled event rate was 6.9 per 100 patient-years among patients with and 2.6 per 100 patient-years among patients without mental stress-induced ischemia. The multivariable adjusted hazard ratio (HR) for patients with vs those without mental stress-induced ischemia was 2.5 (95% CI, 1.8-3.5). Compared with patients with no ischemia (event rate, 2.3 per 100 patient-years), patients with mental stress-induced ischemia alone had a significantly increased risk (event rate, 4.8 per 100 patient-years; HR, 2.0; 95% CI, 1.1-3.7) as did patients with both mental stress ischemia and conventional stress ischemia (event rate, 8.1 per 100 patient-years; HR, 3.8; 95% CI, 2.6-5.6). Patients with conventional stress ischemia alone did not have a significantly increased risk (event rate, 3.1 per 100 patient-years; HR, 1.4; 95% CI, 0.9-2.1). Patients with both mental stress ischemia and conventional stress ischemia had an elevated risk compared with patients with conventional stress ischemia alone (HR, 2.7; 95% CI, 1.7-4.3). The secondary end point occurred in 319 participants. The event rate was 12.6 per 100 patient-years for patients with and 5.6 per 100 patient-years for patients without mental stress-induced ischemia (adjusted HR, 2.0; 95% CI, 1.5-2.5).

CONCLUSIONS AND RELEVANCE

Among patients with stable coronary heart disease, the presence of mental stress-induced ischemia, compared with no mental stress-induced ischemia, was significantly associated with an increased risk of cardiovascular death or nonfatal myocardial infarction. Although these findings may provide insights into mechanisms of myocardial ischemia, further research is needed to assess whether testing for mental stress-induced ischemia has clinical value.

Neoadjuvant Therapy for Resectable Pancreatic Cancer: A New Standard of Care. Pooled Data From 3 Randomized Controlled Trials

OBJECTIVE

The aim of this study was to pool data from randomized controlled trials (RCT) limited to resectable pancreatic ductal adenocarcinoma (PDAC) to determine whether a neoadjuvant therapy impacts on disease-free survival (DFS) and surgical outcome.

SUMMARY BACKGROUND DATA

Few underpowered studies have suggested benefits from neoadjuvant chemo (± radiation) for strictly resectable PDAC without offering conclusive recommendations.

METHODS

Three RCTs were identified comparing neoadjuvant chemo (± radio) therapy vs. upfront surgery followed by adjuvant therapy in all cases. Data were pooled targeting DFS as primary endpoint, whereas overall survival (OS), postoperative morbidity, and mortality were investigated as secondary endpoints. Survival endpoints DFS and OS were compared using Cox proportional hazards regression with study-specific baseline hazards.

RESULTS

A total of 130 patients were randomized (56 in the neoadjuvant and 74 in the control group). DFS was significantly longer in the neoadjuvant treatment group compared to surgery only [hazard ratio (HR) 0.6, 95% confidence interval (CI) 0.4-0.9] (P = 0.01). Furthermore, DFS for the subgroup of R0 resections was similarly longer in the neoadjuvant treated group (HR 0.6, 95% CI 0.35-0.9, P = 0.045). Although postoperative complications (Comprehensive Complication Index, CCI®) occurred less frequently (P = 0.008), patients after neoadjuvant therapy experienced a higher toxicity, but without negative impact on oncological or surgical outcome parameters.

CONCLUSION

Neoadjuvant therapy can be offered as an acceptable standard of care for patients with purely resectable PDAC. Future research with the advances of precision oncology should now focus on the definition of the optimal regimen.

Individual Patient Data Meta-Analysis and Network Meta-Analysis

Meta-analyses are often conducted using trial-level summary data. However, when individual patient data (IPD ) is available, there is greater flexibility in the analysis and a wider range of statistical models that can be fitted. There are two approaches to fitting IPD models. The traditional two-stage approach involves analyzing each trial individually in the first stage and then combining trial estimates of treatment effectiveness in the second stage using methods developed for aggregate data meta-analysis. Growing in popularity is the one-stage approach in which trials are analyzed and synthesized within one statistical model whilst the clustering of patients within trials is accounted for. This chapter outlines both fixed effect and random effects one- and two-stage meta-analysis models for continuous, binary, and time-to-event outcomes. The meta-analysis framework is then extended to the scenario where there are more than two treatments and network meta-analysis models are described.The availability of IPD provides greater statistical power for investigating interactions between treatments and covariates. Treatment-covariate interactions contain both within- and across-trial information where the across-trial information may be subject to ecological bias. This chapter presents network meta-analysis models separating out the within- and across-trial information and finishes by considering practical solutions for dealing with missing covariate data, assessing the consistency assumption, combining IPD and aggregate data and specific considerations for time-to-event outcomes.

Survival analysis between laparoscopic and open hepatectomy for hepatocellular carcinoma: a meta-analysis based on reconstructed time-to-event data

BACKGROUND/PURPOSE OF THE STUDY

Laparoscopic hepatectomy (LH) has been widely used in the treatment of hepatocellular carcinoma (HCC). It is generally believed that the long-term outcomes of LH are not inferior to open hepatectomy (OH). However, the quality of evidence is low. The purpose of this study was to reconstruct time-to-event data for meta-analysis based on Kaplan-Meier curves from propensity-score matched studies and compare survival rates following LH and OH for hepatocellular carcinoma.

METHODS

All published propensity-score matched studies reported in English that compared LH and OH for hepatocellular carcinoma with Kaplan-Meier curves were screened. Patients' survival information was reconstructed with the aid of a computer vision program. Different models (fixed-effects model for two-stage survival analysis and Cox regression for one-stage survival analysis) were performed for sensitivity analysis. In addition to the primary meta-analysis, two specific subgroup analyses were performed on patients by types of resection, cirrhosis status.

RESULTS

Time-to-event data were extracted from 45 propensity-score matched studies (N = 8905). According to the time-to-event data and the reconstructed Kaplan-Meier curves, the cumulative overall survival rate was 49.0% and 50.9% in the LH and OH cohorts, respectively, a log-rank test did not demonstrate statistical significance (p > 0.05). The cumulative recurrence-free survival (RFS) probability was both close to 0.0%. The median RFS time was 49.1 (95% CI 46.1 ~ 51.7) and 44.3 (95% CI 41 ~ 46.1) months. The difference in disease status was statistically significant by the Log-rank test (p < 0.05). Using the random-effects model of two-stage analysis, the minor hepatectomy subgroup (HR = 1.32, 95% CI [1.09, 1.55], I² = 6.2%, p = 0.383) and the shared fragile model of one-stage analysis (HR = 1.44 95% CI [1.23, 1.69], p < 0.001) suggested that LH could significantly prolong RFS of patients compared with OH. This result was consistent with sensitivity analysis using different models.

CONCLUSION

This study was the first reconstructed time-to-event data based on a high-quality propensity-score matching study to compare the survival outcomes of LH and OH in the treatment of HCC. Results suggested that LH can improve RFS in patients with HCC undergoing minor hepatectomy and may also benefit long-term RFS in overall patients.

Association of metabolic-bariatric surgery with long-term survival in adults with and without diabetes: a one-stage meta-analysis of matched cohort and prospective controlled studies with 174 772 participants

BACKGROUND

Metabolic-bariatric surgery delivers substantial weight loss and can induce remission or improvement of obesity-related risks and complications. However, more robust estimates of its effect on long-term mortality and life expectancy-especially stratified by pre-existing diabetes status-are needed to guide policy and facilitate patient counselling. We compared long-term survival outcomes of severely obese patients who received metabolic-bariatric surgery versus usual care.

METHODS

We did a prespecified one-stage meta-analysis using patient-level survival data reconstructed from prospective controlled trials and high-quality matched cohort studies. We searched PubMed, Scopus, and MEDLINE (via Ovid) for randomised trials, prospective controlled studies, and matched cohort studies comparing all-cause mortality after metabolic-bariatric surgery versus non-surgical management of obesity published between inception and Feb 3, 2021. We also searched grey literature by reviewing bibliographies of included studies as well as review articles. Shared-frailty (ie, random-effects) and stratified Cox models were fitted to compare all-cause mortality of adults with obesity who underwent metabolic-bariatric surgery compared with matched controls who received usual care, taking into account clustering of participants at the study level. We also computed numbers needed to treat, and extrapolated life expectancy using Gompertz proportional-hazards modelling. The study protocol is prospectively registered on PROSPERO, number CRD42020218472.

FINDINGS

Among 1470 articles identified, 16 matched cohort studies and one prospective controlled trial were included in the analysis. 7712 deaths occurred during 1·2 million patient-years. In the overall population consisting 174 772 participants, metabolic-bariatric surgery was associated with a reduction in hazard rate of death of 49·2% (95% CI 46·3-51·9, p<0·0001) and median life expectancy was 6·1 years (95% CI 5·2-6·9) longer than usual care. In subgroup analyses, both individuals with (hazard ratio 0·409, 95% CI 0·370-0·453, p<0·0001) or without (0·704, 0·588-0·843, p<0·0001) baseline diabetes who underwent metabolic-bariatric surgery had lower rates of all-cause mortality, but the treatment effect was considerably greater for those with diabetes (between-subgroup I² 95·7%, p<0·0001). Median life expectancy was 9·3 years (95% CI 7·1-11·8) longer for patients with diabetes in the surgery group than the non-surgical group, whereas the life expectancy gain was 5·1 years (2·0-9·3) for patients without diabetes. The numbers needed to treat to prevent one additional death over a 10-year time frame were 8·4 (95% CI 7·8-9·1) for adults with diabetes and 29·8 (21·2-56·8) for those without diabetes. Treatment effects did not appear to differ between gastric bypass, banding, and sleeve gastrectomy (I² 3·4%, p=0·36). By leveraging the results of this meta-analysis and other published data, we estimated that every 1·0% increase in metabolic-bariatric surgery utilisation rates among the global pool of metabolic-bariatric candidates with and without diabetes could yield 5·1 million and 6·6 million potential life-years, respectively.

INTERPRETATION

Among adults with obesity, metabolic-bariatric surgery is associated with substantially lower all-cause mortality rates and longer life expectancy than usual obesity management. Survival benefits are much more pronounced for people with pre-existing diabetes than those without.

FUNDING

None.

Developing more generalizable prediction models from pooled studies and large clustered data sets

Prediction models often yield inaccurate predictions for new individuals. Large data sets from pooled studies or electronic healthcare records may alleviate this with an increased sample size and variability in sample characteristics. However, existing strategies for prediction model development generally do not account for heterogeneity in predictor‐outcome associations between different settings and populations. This limits the generalizability of developed models (even from large, combined, clustered data sets) and necessitates local revisions. We aim to develop methodology for producing prediction models that require less tailoring to different settings and populations. We adopt internal‐external cross‐validation to assess and reduce heterogeneity in models' predictive performance during the development. We propose a predictor selection algorithm that optimizes the (weighted) average performance while minimizing its variability across the hold‐out clusters (or studies). Predictors are added iteratively until the estimated generalizability is optimized. We illustrate this by developing a model for predicting the risk of atrial fibrillation and updating an existing one for diagnosing deep vein thrombosis, using individual participant data from 20 cohorts (N = 10 873) and 11 diagnostic studies (N = 10 014), respectively. Meta‐analysis of calibration and discrimination performance in each hold‐out cluster shows that trade‐offs between average and heterogeneity of performance occurred. Our methodology enables the assessment of heterogeneity of prediction model performance during model development in multiple or clustered data sets, thereby informing researchers on predictor selection to improve the generalizability to different settings and populations, and reduce the need for model tailoring. Our methodology has been implemented in the R package metamisc.

ABO blood types and sepsis mortality

Background

We aimed to determine if the ABO blood types carry different risks of 30-day mortality, acute kidney injury (AKI), and endothelial damage in critically ill patients with sepsis. This was a retrospective cohort study of three independent cohorts of critically ill patients from the United States and Scandinavia consisting of adults with septic shock. We compared the 30-day mortality across the blood types within each cohort and pooled the results in a meta-analysis. We also estimated the incidence of AKI and degree of endothelial damage, as measured by blood concentrations of soluble thrombomodulin and syndecan-1.

Results

We included 12,342 patients with severe sepsis. In a pooled analysis blood type B carried a slightly lower risk of 30-day all-cause mortality compared to non-blood type B (adjusted HR 0.88; 95%-CI 0.79–0.98; p = 0.02). There was no difference in the risk of AKI. Soluble thrombomodulin and syndecan-1 concentrations were lower in patients with blood type B and O compared to blood type A, suggesting less endothelial damage.

Conclusion

Septic patients with blood type B had less endothelial damage, and a small reduction in mortality. The exposure is, however, unmodifiable.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00844-2.

Cervical chordomas: multicenter case series and meta-analysis

BACKGROUND

En bloc spondylectomy is the gold standard for surgical resection of sacral chordomas (CHO), but the effect of extent of resection on recurrence and survival in patients with CHO of the cervical spine remains elusive.

METHODS

MEDLINE, Embase, Scopus, and Cochrane were systematically reviewed. Patients with cervical CHO treated at three tertiary-care academic institutions were reviewed for inclusion. We performed an individual participant data meta-analysis to assess the overall survival (OS) and progression free survival (PFS) after en bloc-gross total resection (GTR) and intralesional-GTR compared to subtotal resection (STR). We then performed an intention-to-treat analysis including all patients with attempted en bloc resection in the en bloc group, regardless of the surgical margins.

RESULTS

There was a total of 13 series including 161 patients with cervical CHO, including our current series of 22 patients. GTR (en bloc-GTR + intralesional-GTR) was associated with a significant decrease in the risk of local progression (pooled hazard ratio (PHR) = 0.22; 95% CI 0.08-0.59; p = 0.003) and risk of death (PHR 0.31; 95%; CI 0.12-0.83; p = 0.020). A meta-regression analyses determined that intralesional-GTR improved PFS (PHR 0.35; 95% CI 0.16-0.76; p = 0.009) as well as OS (PHR 0.25; 95% CI 0.08-0.79; p = 0.019) when compared to STR. En bloc-GTR was associated with a significant reduction in the risk of local progression (PHR 0.06; 95% CI 0.01-0.77; p = 0.030), but not a decreased OS (PHR 0.50; 95% CI 0.19-1.27; p = 0.145). Our intention-to-treat analyses revealed a near significant improvement in OS for the en bloc group (PHR: 0.15; 95% CI 0.02-1.22; p = 0.054), and nearly identical improvement in PFS. Radiation data was not available for the studies included in the meta-analysis.

CONCLUSION

This is the first and only meta-analysis of patients with cervical CHO. We found that both en bloc-GTR and intralesional-GTR resulted in improved local tumor control when compared to STR.

Classification and effectiveness of different oxygenation goals in mechanically ventilated critically ill patients: network meta-analysis of randomised controlled trials

BACKGROUND

The optimal oxygenation in mechanically ventilated critically ill patients remains unclear.

METHODS

Randomised controlled trials investigating different oxygenation goal-directed mechanical ventilation in critically ill adult patients were eligible. The trinary classification classified oxygenation goals into conservative (PaO₂=55-90 mmHg), moderate (PaO₂=90-150 mmHg), and liberal (PaO₂>150 mmHg). The quadruple classification further divided the conservative goal from the trinary classification into far-conservative (PaO₂=55-70 mmHg) and conservative (PaO₂=70-90 mmHg) goals. The primary outcome was 30-day mortality. The secondary outcomes included intensive care unit, hospital, and 90-day mortalities. The effectiveness was estimated by the relative risk (RR) and 95% credible interval (CrI) using network meta-analysis and visualised using SUCRA scores and survival curves.

RESULTS

We identified eight eligible studies involving 2532 patients. There were no differences between conservative and moderate goals (RR, 1.08; 95% CrI, 0.85 to 1.36; moderate quality), between moderate and liberal goals (RR, 0.83; 95% CrI, 0.61 to 1.10, low quality), and between conservative and liberal goals (RR, 0.89; 95% CrI, 0.61 to 1.30, low quality) based on the trinary classification. No differences in secondary outcomes among the different goals. The results were consistent between the trinary and quadruple classifications. The SUCRA scores and survival curves suggested that the moderate goal in the trinary and quadruple classifications and the conservative goal in the quadruple classification may be superior to the liberal and far-conservative goals.

CONCLUSIONS

Different oxygenation goals do not lead to different mortalities in mechanically ventilated critically ill patients. The potential superiority of maintaining PaO₂ in the range of 70-150 mmHg remains to be validated.

Individual participant data meta-analysis of intervention studies with time-to-event outcomes: A review of the methodology and an applied example

Many randomized trials evaluate an intervention effect on time-to-event outcomes. Individual participant data (IPD) from such trials can be obtained and combined in a so-called IPD meta-analysis (IPD-MA), to summarize the overall intervention effect. We performed a narrative literature review to provide an overview of methods for conducting an IPD-MA of randomized intervention studies with a time-to-event outcome. We focused on identifying good methodological practice for modeling frailty of trial participants across trials, modeling heterogeneity of intervention effects, choosing appropriate association measures, dealing with (trial differences in) censoring and follow-up times, and addressing time-varying intervention effects and effect modification (interactions).We discuss how to achieve this using parametric and semi-parametric methods, and describe how to implement these in a one-stage or two-stage IPD-MA framework. We recommend exploring heterogeneity of the effect(s) through interaction and non-linear effects. Random effects should be applied to account for residual heterogeneity of the intervention effect. We provide further recommendations, many of which specific to IPD-MA of time-to-event data from randomized trials examining an intervention effect.We illustrate several key methods in a real IPD-MA, where IPD of 1225 participants from 5 randomized clinical trials were combined to compare the effects of Carbamazepine and Valproate on the incidence of epileptic seizures.