Citation of Previous Meta-analyses on the Same Topic

Abstract

Clinical relevance Systematic reviews and meta-analyses serve as a basis for decision-making and clinical practice guidelines and should be carried out using appropriate methodology to avoid incorrect inferences. Topic We describe the characteristics, statistical methods used for meta-analyses, and citation patterns of all 21 glaucoma systematic reviews we identified pertaining to the effectiveness of prostaglandin analog eye drops in treating primary open-angle glaucoma, published between December 2000 and February 2012. Methods We abstracted data, assessed whether appropriate statistical methods were applied in meta-analyses, and examined citation patterns of included reviews. Results We identified two forms of problematic statistical analyses in 9 of the 21 systematic reviews examined. Except in 1 case, none of the 9 reviews that used incorrect statistical methods cited a previously published review that used appropriate methods. Reviews that used incorrect methods were cited 2.6 times more often than reviews that used appropriate statistical methods. We speculate that by emulating the statistical methodology of previous systematic reviews, systematic review authors may have perpetuated incorrect approaches to meta-analysis. Conclusions The use of incorrect statistical methods, perhaps through emulating methods described in previous research, calls conclusions of systematic reviews into question and may lead to inappropriate patient care. We urge systematic review authors and journal editors to seek the advice of experienced statisticians before undertaking or accepting for publication a systematic review and meta-analysis.

Comparative Effectiveness of First-Line Medications for Primary Open-Angle Glaucoma

“…Conventional pair-wise meta-analyses, summarizing these RCTs, can only answer questions where RCTs exist and can only examine pairs of interventions. 9 This does not support real world clinical decision-making because each meta-analysis only takes into account one part of the overall range of choice. It is also worth noting that 43% of pair-wise meta-analyses published up to February 2012 on glaucoma medications used problematic statistical analyses, calling conclusions from these meta-analyses and systematic reviews into question.…”

“…It is also worth noting that 43% of pair-wise meta-analyses published up to February 2012 on glaucoma medications used problematic statistical analyses, calling conclusions from these meta-analyses and systematic reviews into question. 9 One common error was that the review authors pooled data by treatment group rather than analyzing the between group effect estimates, breaking the randomized nature of trials. 9 We used three approaches to examine the inconsistency assumption for our network meta-analysis and found that this assumption is likely to hold in our analysis.…”

Interventions for Age-Related Macular Degeneration

“…100,101 In some cases, existing reviews were unreliable because of the lack of adherence to reporting standards and use of systematic review methodology aimed at minimizing selection and reporting biases. Publication of unreliable reviews represents a waste of resources.…”

Network Meta-analysis for Clinical Practice Guidelines: A Case Study on First-Line Medical Therapies for Primary Open-Angle Glaucoma

“…For example, the validity of the results of a network meta-analysis depends on the validity of the assumptions being made, the results depend on the network definitions applied, and the treatment rankings are associated with uncertainty. Although these issues have been discussed extensively in the network meta-analysis literature (5, 6, 45, 46), they may not be familiar to guidelines producers and clinicians.…”