The methodological quality was low and conclusions discordant for meta-analyses comparing proximal humerus fracture treatments: a meta-epidemiological study

Transitivity, coherence, and reliability of network meta-analyses comparing proximal humerus fracture treatments: a meta-epidemiological study

BACKGROUND

Network meta-analyses can be valuable for decision-makers in guiding clinical practice. However, for network meta-analysis results to be reliable, the assumptions of both transitivity and coherence must be met, and the methodology should adhere to current best practices. We aimed to assess whether network meta-analyses of randomized controlled trials (RCTs) comparing interventions for proximal humerus fractures provide reliable estimates of intervention effects.

METHODS

We searched PubMed, EMBASE, The Cochrane Library, and Web of Science for network meta-analyses comparing interventions for proximal humerus fractures. We critically assessed the methodology regarding the development of a protocol, search strategy, trial inclusion, outcome extraction, and the methods used to conduct the network meta-analyses. We assessed the transitivity and coherence of the network graphs for the Constant score (CS), Disabilities of the Arm, Shoulder, and Hand score (DASH), and additional surgery. Transitivity was assessed by comparing probable effect modifiers (age, gender, fracture morphology, and comorbidities) across intervention comparisons. Coherence was assessed using Separating Indirect from Direct Evidence (SIDE) (Separating Indirect from Direct Evidence) and the design-by-treatment interaction test. We used CINeMA (Confidence in Network Meta-analyses) to assess the confidence in the results.

RESULTS

None of the three included network meta-analyses had a publicly available protocol or data-analysis plan, and they all had methodological flaws that could threaten the validity of their results. Although we did not detect incoherence for most comparisons, the transitivity assumption was violated for CS, DASH, and additional surgery in all three network meta-analyses. Additionally, the confidence in the results was 'very low' primarily due to within-study bias, reporting bias, intransitivity, imprecision, and heterogeneity.

CONCLUSIONS

Current network meta-analyses of RCTs comparing interventions for proximal humerus fractures do not provide reliable estimates of intervention effects. We advise caution in using these network meta-analyses to guide clinical practice. To improve the utility of network meta-analyses to guide clinical practice, journal editors should require that network meta-analyses are done according to a predefined analysis plan in a publicly available protocol and that both coherence and transitivity have been adequately assessed and reported.

Replication of systematic reviews: is it to the benefit or detriment of methodological quality?

OBJECTIVES

To perform an overview of the overlap of systematic reviews (SRs) assessing direct oral anticoagulants and characterize these reviews in terms of bias and methodological quality (PROSPERO: CRD42022316273).

STUDY DESIGN AND SETTING

A PubMed-indexed search was performed from inception to January 31, 2022 to identify SRs evaluating direct oral anticoagulants in patients treated for an acute venous thromboembolism. The risk of bias of these SRs was assessed according to the Risk Of Bias In Systematic reviews tool. Redundancy was defined as overlap in terms of the type of population considered, the interventions compared, and the studies included.

RESULTS

A total of 144 SRs were evaluated, of which 26 (18.1%) were classified as original, 87 (60.4%) as conceptual replications, and 31 (21.5%) as excessive replications. The risk of bias was high in 19 (73.1%) of the original SRs, 65 (74.7%) of the conceptual replications, and 21 (67.7%) of the excessive replications. Compared to the original SRs, the overall methodological quality was not improved in either conceptual or excessive replications.

CONCLUSION

A large number of SRs was classified as replications; a fifth constituted excessive replications. The replications showed no improvement in overall methodological quality compared to the original SRs.

A meta-epidemiological study found that meta-analyses of the same trials may obtain drastically conflicting results

OBJECTIVES

To assess how much protocols reduce methodological flexibility and variation of results in meta-analyses comparing operative with nonoperative treatments for proximal humerus fractures.

STUDY DESIGN AND SETTING

A meta-epidemiological study. We searched four bibliographic databases for eligible meta-analyses. We contacted the authors of the meta-analyses, requesting a copy of their protocol. We identified the included studies and extracted intervention effect data for functional outcome, quality of life, and adverse events. Using the same intervention effect data for each outcome domain, we conducted multiple meta-analyses using differing combinations of methodological choices (analytical scenarios) without restricting the available methodological choices (as if no protocol was used). For each protocol, we repeated this process but restricted the available choices to those listed in the protocol. We then compared the distributions of effect estimates with and without protocols. Methodological flexibility was estimated as the difference in number of possible meta-analyses and the variation of results as the difference between the most conflicting effect estimates.

RESULTS

We identified 23 meta-analyses, included 24 primary studies, and obtained three protocols. The protocols markedly reduced methodological flexibility (range for functional outcomes 94%-99%; quality of life 58%-76%; adverse events 87%-91%). The corresponding reduction in the variation of the results varied (range for functional outcomes; 33%-78%, quality of life; 10%-24%; adverse events 10%-13%).

CONCLUSION

Although the protocols consistently reduced methodological flexibility, the reduction in the variation (bias) of results varied. Consequently, review authors may obtain conflicting results based on the same data. We advise caution when interpreting the conclusions of meta-analyses with absent or imprecise protocols.