Generalizability of findings from systematic reviews and meta-analyses in the Leading General Medical Journals.

OBJECTIVE

To assess how items relevant for the assessment of the generalizability of findings from randomized controlled trials were recorded in systematic reviews published in leading general medical journals.

METHODS

All systematic reviews and meta-analyses published in the Annals of Internal Medicine, BMJ, JAMA (The Journal of the American Medical Association) and Lancet from 1 January 2016 to 28 February 2019 were searched via PubMed. Reporting of the characteristics of randomized controlled trials in the systematic reviews was documented by the benchmarking method.

RESULTS

A total of 115 systematic reviews were found. Of these, 71% included pharmacological interventions, 35% included other conservative treatments, 13% included surgical interventions, and 0% included rehabilitation interventions. None of the systematic reviews assessed patient selection, 35% reported disorder-specific clinical features, 25 % reported comorbid conditions, and 21% reported patients' behavioural factors in randomized controlled trials. Functioning, environmental factors and inequity-related factors were recorded in 3%, 0% and 9%, respectively, of the systematic reviews; and adherence to interventions, crossovers, and co-interventions in 7%, 0% and 2%, respectively; follow-up percentages in 8%; and adequacy of statistical analyses in 3%.

CONCLUSION

In all systematic reviews the recording of characteristics of patients, adherence to interventions, follow-up, and statistical analyses in the RCTs was insufficient. The data did not allow assessment of the clinical homogeneity of the randomized controlled trials, or provide justification for meta-analysis, or allow generalizability of the findings.