Moose on the loose: checklist for meta-analyses of observational studies

Abstract

The aims and scope of the British Journal of Dermatology clearly underline that ‘The BJD strives to publish the highest‐quality dermatological research’, with an understanding that submissions need to adhere to internationally accepted standards and quality criteria. Compliance with these criteria will expedite the transition of a submission through the peer‐reviewing process, and most importantly add value to a manuscript. Most researchers conducting clinical trials will already be familiar with the Consolidated Standards of Reporting Trials (CONSORT) guidelines for randomized controlled trials (RCTs) and with the STrengthening the Reporting of Observational studies in Epidemiology (STROBE) guidelines for observational studies. However, neither of these guidelines is directly applicable to systematic reviews. In 2009 the Preferred Reporting Items for Systematic reviews and Meta‐Analyses (PRISMA) statement was released in several key international journals such as the BMJ, PLoS Medicine, Annals of Internal Medicine and Journal of Clinical Epidemiology.1 This important step has progressively enhanced the quality of conduct and reporting of systematic reviews.1 Systematic reviews and meta‐analyses have gained in importance and are increasingly used as the basis for clinical guideline development. Conducting a systematic review can be very time‐consuming and it is important that the methodology as well as the results are reported in a structured standardized and above all transparent manner. The PRISMA checklist, which consists of 27 items, provides clear guidance to review authors on how to improve the reporting of their systematic review and meta‐analysis.1 PRISMA is predominantly used for systematic reviews and meta‐analyses evaluating RCTs. However, not all evidence can be synthesized from RCTs or in many cases it is not feasible to conduct RCTs or they are not available.2 The results from observational studies can be regarded as complementary to the findings of RCTs and may more accurately reflect the effects in the real world by providing long‐term data on both the effectiveness and adverse events of interventions.3,4 Observational studies can also offer additional advantages over other study designs by identifying and summarizing infrequent or rare adverse events, more especially as the number of patients is generally much larger (especially when large databases are used). This form of study design may also include a more diverse and clinically heterogeneous patient population and a longer follow‐up period.4 However, the major limitations of observational studies are their inability to avoid or balance sources of bias (e.g. selection bias) and in eliminating possible confounding factors (e.g. differences in disease severity).2,3,4 The 35‐item checklist, Meta‐analysis Of Observational Studies in Epidemiology (MOOSE) has been developed to address some of these issues and to allow for a more standardized reporting of meta‐analyses of observational studies.2 Although there is a measure of coherence between the PRISMA and MOOSE checklists, the MOOSE checklist pays far more attention to certain aspects of the search strategy, in particular the inclusion of unpublished and non‐English‐language studies.5 As it is recognized that observational studies are more prone to bias and confounding, greater emphasis is also placed on the quality assessment of the individual studies and in the detection of publication bias.2,5 The checklist recommends that the Discussion and Conclusion of the meta‐analysis should also include elaborations of other possible explanations for the results as reported.2 In line with the submission requirements of other peer‐reviewed journals all systematic reviews and meta‐analyses of observational studies submitted to the BJD will now need to be accompanied by a completed MOOSE checklist. Although guidelines and checklists are provided to help authors ensure the quality of their submitted manuscripts, an increased awareness of these guidelines and checklists is also needed by the peer reviewers.6 Peer reviewers should not only be referred to the Committee on Publication Ethics (COPE) guidelines but also be alerted to the additional guidelines and checklists that authors are required to comply with during manuscript submission.6 Male moose takes a rest in a field during a light rain shower. Photographer Ryan Hagerty, U.S. Fish and Wildlife Service. Picture is in the public domain and is freely available at http://www.public-domain-image.com/free-images/fauna-animals/deers/moose-and-elk/a-male-moose-takes-a-rest-in-a-field-during-a-light-rainshower/attachment/a-male-moose-takes-a-rest-in-a-field-during-a-light-rainshower. No external funding. None declared.