A systematic review identifies shortcomings in the reporting of crossover trials in chronic painful conditions

A systematic review of the quality of reporting and risk of bias for randomized crossover trials in digestive disease journals

BACKGROUND

The quality of randomized crossover studies on digestive diseases is unclear. We aimed to review crossover trials in digestive disease journals and evaluate their reporting quality and risk of bias.

METHODS

We searched the PubMed, Web of Science, and Scopus databases for all crossover trials in 39 digestive journals between January 2011 and September 2021. Reporting adherence was based on the CONSORT 2010 statement: extension to randomized crossover trials published in July 2019. A newly released Cochrane risk of bias tool 2.0 extension for crossover trials was applied to assess the risk of bias.

RESULTS

In total, 173 studies were included in the analysis, and 16.2% were published following the CONSORT statement extension. The crossover design was not only widely used in drug efficacy trials (48.6%) but also in endoscopic ultrasound trials (23.7%) and dietary studies (17.9%) in the field of digestive diseases. The overall reporting adherence was 37.6% for full texts and 43.4% for abstracts. The proportions of trials with low, some concerns, and high risk of bias were 13.9%, 15.6%, and 70.5%, respectively. The difference in reporting adherence and high risk of bias between pre- and post-CONSORT was not significant. Having a sample size plan, defining primary end points, and pre-registration showed higher reporting adherence and lower risk of bias than those who did not.

CONCLUSION

These findings demonstrated the inadequate quality of randomized crossover trials for digestive diseases. Compliance with the CONSORT extension for crossover trials must be strengthened and improved (PROSPERO CRD: 42021248723).

The crossover design for studies of infertility employing in-vitro fertilization: A methodological survey

Background

Infertility has become increasingly common worldwide. There is a need for the infertility literature to evaluate new interventions with IVF. The crossover design presents many methodological advantages for IVF trials. In addition to providing a within-person comparison of outcomes, it offers participants the opportunity to potentially benefit from more than one available treatment. However, infertility studies present a unique challenge in terms of bias: successful participants do not cross over to the second treatment group.

Objectives

The main objective of our study was to survey the methodological features of crossover trials for infertility with in-vitro fertilization (IVF) based interventions. A secondary focus was reporting key results.

Study design & setting

We conducted a methodological survey by systematically searching Medline and Embase databases. The capture-recapture technique was used to estimate the number of relevant studies that were not retrieved by our search strategy. We employed the Cochrane risk of bias tool to assess methodological rigour. Crossover-specific methods features were summarized. Treatment effects for pregnancy outcomes across studies are also presented.

Results

15 studies met inclusion criteria. Most studies were deemed to have high or unclear risks of bias, usually because of incomplete reporting of outcome data and assessment procedures. 13 studies did not employ crossover-specific methods to analyze outcome data by period, which may bias treatment effect estimates. Four studies reported pregnancy outcome data with sample sizes from both treatment periods. Of these four studies, three reported that the control intervention was favoured.

Conclusions

The main limitation of our survey was the small sample size of studies. Future reviews should be larger and seek to encompass a broader range of the infertility literature. Despite the issues identified in the included trials, consideration should still be given to using the crossover design in future infertility research. Employing crossover-specific analysis methods, such as accounting for participant non-completion, along with strict adherence to CONSORT reporting guidelines, may significantly reduce the risk of bias in individual studies.

Reporting of cross-over clinical trials of analgesic treatments for chronic pain: Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks systematic review and recommendations

Cross-over trials are typically more efficient than parallel group trials in that the sample size required to yield a desired power is substantially smaller. It is important, however, to consider some issues specific to cross-over trials when designing and reporting them, and when evaluating the published results of such trials. This systematic review evaluated the quality of reporting and its evolution over time in articles of cross-over clinical trials of pharmacologic treatments for chronic pain published between 1993 and 2013. Seventy-six (61%) articles reported a within-subject primary analysis, or if no primary analysis was identified, reported at least 1 within-subject analysis, which is required to achieve the gain in power associated with the cross-over design. For 39 (31%) articles, it was unclear whether analyses conducted were within-subject or between-group. Only 36 (29%) articles reported a method to accommodate missing data (eg, last observation carried forward, n = 29), and of those, just 14 included subjects in the analysis who provided data from only 1 period. Of the articles that identified a within-subject primary analysis, 21 (51%) provided sufficient information for the results to be included in a meta-analysis (ie, estimates of the within-subject treatment effect and variability). These results and others presented in this article demonstrate deficiencies in reporting of cross-over trials for analgesic treatments. Clearer reporting in future trials could improve readers' ability to critically evaluate the results, use these data in meta-analyses, and plan future trials. Recommendations for proper reporting of cross-over trials that apply to any condition are provided.

A systematic review finds underreporting of ethics approval, informed consent, and incentives in clinical trials

OBJECTIVES

In this study, we aim to review researchers' reporting practices of the ethics statement, financial incentives, and local ethical committees' profile in their clinical trials.

STUDY DESIGN AND SETTING

A systematic search was done through top-ranked 50 medical journals (Scimago Ranking) to retrieve 2,000 latest publications. Only primary clinical trials were included with no restriction to language or participants.

RESULTS

Among the 927 included trials, 14 trials (1.5%) did not report an ethical statement and two-third (63%) did not completely report the investigated components (Institutional Review eBoard approval, Helsinki Declaration, and informed consent). Moreover, 21 trials (2.26%) reported motivational incentives with the method and amount of payment for participants. Of them, 15 trials offered monetary incentives to participants in different forms. In the remaining six trials, the incentives were mainly medical benefits. Only one trial reported the profile or quality of local Institutional Review Board.

CONCLUSION

A potential gap in the reporting practices of ethics statement and financial incentives was addressed in this review. Authors are urged to fully report all ethical components related to their study, including incentives and compensations plan. Medical journals are also recommended to implement further publication requirements concerning ethics reporting.

An Unconditional Test for Change Point Detection in Binary Sequences with Applications to Clinical Registries

OBJECTIVES

Methods for change point (also sometimes referred to as threshold or breakpoint) detection in binary sequences are not new and were introduced as early as 1955. Much of the research in this area has focussed on asymptotic and exact conditional methods. Here we develop an exact unconditional test.

METHODS

An unconditional exact test is developed which assumes the total number of events as random instead of conditioning on the number of observed events. The new test is shown to be uniformly more powerful than Worsley's exact conditional test and means for its efficient numerical calculations are given. Adaptions of methods by Berger and Boos are made to deal with the issue that the unknown event probability imposes a nuisance parameter. The methods are compared in a Monte Carlo simulation study and applied to a cohort of patients undergoing traumatic orthopaedic surgery involving external fixators where a change in pin site infections is investigated.

RESULTS

The unconditional test controls the type I error rate at the nominal level and is uniformly more powerful than (or to be more precise uniformly at least as powerful as) Worsley's exact conditional test which is very conservative for small sample sizes. In the application a beneficial effect associated with the introduction of a new treatment procedure for pin site care could be revealed.

CONCLUSIONS

We consider the new test an effective and easy to use exact test which is recommended in small sample size change point problems in binary sequences.

Deficiencies of effectiveness of intervention studies in veterinary medicine: a cross-sectional survey of ten leading veterinary and medical journals

The validity of studies that assess the effectiveness of an intervention (EoI) depends on variables such as the type of study design, the quality of their methodology, and the participants enrolled. Five leading veterinary journals and 5 leading human medical journals were hand-searched for EoI studies for the year 2013. We assessed (1) the prevalence of randomized controlled trials (RCTs) among EoI studies, (2) the type of participants enrolled, and (3) the methodological quality of the selected studies. Of 1707 eligible articles, 590 were EoI articles and 435 RCTs. Random allocation to the intervention was performed in 52% (114/219; 95%CI:45.2-58.8%) of veterinary EoI articles, against 87% (321/371; 82.5-89.7%) of human EoI articles (adjusted OR:9.2; 3.4-24.8). Veterinary RCTs were smaller (median: 26 animals versus 465 humans) and less likely to enroll real patients, compared with human RCTs (OR:331; 45-2441). Only 2% of the veterinary RCTs, versus 77% of the human RCTs, reported power calculations, primary outcomes, random sequence generation, allocation concealment and estimation methods. Currently, internal and external validity of veterinary EoI studies is limited compared to human medical ones. To address these issues, veterinary interventional research needs to improve its methodology, increase the number of published RCTs and enroll real clinical patients.