Core outcomes were rarely reported overall in systematic reviews on acupuncture for osteoarthritis: a cross-sectional meta-epidemiological study.

Objective: To identify a comprehensive list of outcomes and explore the reporting rate of core outcome sets (COS) and related factors in systematic reviews (SRs) of acupuncture for osteoarthritis (OA).

Study design and setting: Databases were searched for the relative SRs. Descriptive statistics were calculated as frequencies and percentages. Binary logistic regression was used to explore the factors affecting the reporting rate of COS.

Results: We included 59 SRs. Outcome measures reported in the SRs were classified into 11 domains and 67 unique outcomes. No SR completely reported COS. In COS released in 2016, 75% of outcomes (6/8) were only reported by ⩽5% SRs. In COS released in 2019, the reporting rate was very low (from 0% to 17%) for 73.3% of outcomes (11/15). SRs published in the most recent 5 years had a significantly greater possibility of reporting COS (odds ratio (OR) = 4.74, 95% confidence interval (CI) = 1.33 to 16.88, p = 0.016).

Conclusion: Core outcomes were rarely reported in systematic reviews of acupuncture for OA, with considerable heterogeneity in the use of outcomes. The publication of COS in the COMET (Core Outcome Measures in Effectiveness Trials) database may help promote the reporting of COS. We encourage systematic reviewers to use relevant COS.