Association between switching of primary outcomes and reported trial findings among randomized drug trials from China

BACKGROUND AND OBJECTIVE

To evaluate the association between the nature of findings and the switching of registered primary outcomes among randomized controlled trials (RCTs) from mainland China.

METHODS

This is a retrospective cohort study. We retrieved RCTs from trial registries and identified the corresponding journal articles from bibliographic databases until August 2019. Trial registries and journal articles were compared to evaluate whether registered primary outcomes with negative findings were more likely to be switched to secondary outcomes in the subsequent journal articles than those with positive findings.

RESULTS

Switching of registered primary outcomes occurred in 131 (45%) of 294 RCTs. A total of 450 registered primary outcomes were matched to 522 (37%) primary outcomes and 871 (63%) secondary outcomes in the journal articles. Among RCTs registered before they started, the odds of switching primary outcomes with negative findings were 2.64 (95% CI: 1.16-6.02) times the odds of switching those with positive findings. Among RCTs registered when they were ongoing, the odds of switching primary outcomes with negative findings were 8.84 (95% CI: 3.62-25.93) times the odds of switching those with positive findings.

CONCLUSION

The nature of findings may play a role in how likely a prespecified primary outcome is switched subsequently.

A multicenter prospective registration study on laparoscopic pancreatectomy in Japan: report on the assessment of 1,429 patients

BACKGROUND

Prospective studies are needed to understand the safety and feasibility of laparoscopic pancreatectomy. The aim of the present study was to describe laparoscopic pancreatectomy currently undertaken in Japan, using a prospective registration system.

METHODS

Patient characteristics and planned operations were registered preoperatively, and then the performed operation and outcomes were reported using an online system. Collected data were also compared between institutions based on their level of experience. This study was registered with UMIN000022836.

RESULTS

Available data were obtained from 1,429 patients at 100 Japanese institutions, including 1,197 laparoscopic distal pancreatectomies (LDPs) and 232 laparoscopic pancreatoduodenectomies (LPDs). The rates of completion for planned operations were 92% for LDP and 91% for LPD. Postoperative complication rates after LDP and LPD were 17% and 30%, and 90-day mortality rates were 0.3% and 0.4%, respectively. Shorter operation time, less blood loss, and lower incidence of pancreatic fistula were observed in institutions experienced in LDP. A higher rate of pure laparoscopic procedure and shorter operation time were noted in institutions experienced with LPD.

CONCLUSION

LDPs and LPDs are performed safely in Japan, especially in experienced institutions. Our data could support the next challenges in the field of laparoscopic pancreatectomy.

Prevalence of trial registration varies by study characteristics and risk of bias

OBJECTIVES

The objective of this study was to determine the prevalence of trial registration in health research, whether trial registration status and timing vary depending on trial characteristics, and the relationship between trial registration status and risk of bias.

STUDY DESIGN AND SETTING

We systematically reviewed all clinical trials published from January to June 2017 in 28 high- and low-impact factor general and specialty medicine journals.

RESULTS

We identified 370 trials and assessed risk of bias in 183 trials. Trial registration rates were high; 95% of trials were registered prospectively or retrospectively before enrollment completion. Larger sample size, multiple recruitment countries, and primary industry funding were all predictors of earlier trial registration. Prospectively registered trials had a significantly lower risk of bias compared to unregistered trials across all domains. Prospectively registered trials had a similar risk of bias compared to retrospectively registered trials across four out of six domains, and a lower risk of bias across the remaining two domains.

CONCLUSION

Trial registration is an imperfect proxy for risk of bias. Systematic reviewers should assess risk of bias on a case-by-case basis and conduct sensitivity analyses excluding high risk of bias studies. In the longer term, mechanisms should be implemented to facilitate prospective registration of all trials.

Association between prospective registration and overall reporting and methodological quality of systematic reviews: a meta-epidemiological study

OBJECTIVES

The aim of this study was to investigate the differences in main characteristics, reporting and methodological quality between prospectively registered and nonregistered systematic reviews.

STUDY DESIGN AND SETTING

PubMed was searched to identify systematic reviews of randomized controlled trials published in 2015 in English. After title and abstract screening, potentially relevant reviews were divided into three groups: registered non-Cochrane reviews, Cochrane reviews, and nonregistered reviews. For each group, random number tables were generated in Microsoft Excel, and the first 50 eligible studies from each group were randomly selected. Data of interest from systematic reviews were extracted. Regression analyses were conducted to explore the association between total Revised Assessment of Multiple Systematic Review (R-AMSTAR) or Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) scores and the selected characteristics of systematic reviews.

RESULTS

The conducting and reporting of literature search in registered reviews were superior to nonregistered reviews. Differences in 9 of the 11 R-AMSTAR items were statistically significant between registered and nonregistered reviews. The total R-AMSTAR score of registered reviews was higher than nonregistered reviews [mean difference (MD) = 4.82, 95% confidence interval (CI): 3.70, 5.94]. Sensitivity analysis by excluding the registration-related item presented similar result (MD = 4.34, 95% CI: 3.28, 5.40). Total PRISMA scores of registered reviews were significantly higher than nonregistered reviews (all reviews: MD = 1.47, 95% CI: 0.64-2.30; non-Cochrane reviews: MD = 1.49, 95% CI: 0.56-2.42). However, the difference in the total PRISMA score was no longer statistically significant after excluding the item related to registration (item 5). Regression analyses showed similar results.

CONCLUSION

Prospective registration may at least indirectly improve the overall methodological quality of systematic reviews, although its impact on the overall reporting quality was not significant.