Presentation approaches for enhancing interpretability of patient-reported outcomes in meta-analyses: a systematic survey of Cochrane reviews

OBJECTIVES: To systematically survey Cochrane reviews' approaches to calculating, presenting, and interpreting pooled estimates of patient-reported outcome measures (PROMs). STUDY DESIGN AND SETTING: We retrospectively selected 200 Cochrane reviews that met the eligibility criteria. Two researchers independently extracted the pooled effect measures and approaches for pooling and interpreting the effect measures, reaching consensus through discussions. RESULTS: When primary studies used the same PROM, Cochrane review authors most often used mean differences (MDs) (81.9%) for calculating the pooled effect measures; when primary studies used different PROMs, the review authors often applied standardized mean differences (SMDs) (54.3%). Although in most cases (80.1%) the review authors interpreted the importance of effect, they failed, in 48.5% of the pooled effect measures, to report criteria for categorizing the magnitude of effect. When authors interpreted the importance of the effect, for those with primary studies using the same PROM, they most often referred to the minimally important differences (MIDs) (75.0%); for those with primary studies using different PROMs, the approaches used varied. CONCLUSION: Cochrane review authors most often used MDs or SMDs for calculating and presenting the pooled effect measures of PROs but often failed to make explicit their criteria for categorizing the magnitude of effect.