More than half of systematic reviews have relevant core outcome sets

Using recent systematic reviews (SRs), our objectives were to: (1) develop a framework to assess whether a given COS is relevant to the scope of a SR; (2) examine the proportion of SRs for which relevant COS exist; and (3) for SRs for which COS exist, examine the extent to which outcomes in the COS and outcomes in the SR match.

We included a sample of SRs published by the Agency for Healthcare Research and Quality Evidence-based Practice Center Program between January 1, 2018 and October 12, 2020. We searched for potentially relevant COS from the Core Outcome Measures for Effectiveness Trials (COMET) database. We assessed the matching between outcomes recommended by COS and those included in corresponding SRs. When outcomes were matched, we considered matches to be specific (i.e., exact) or general (i.e., non-specific).

Sixty-seven SRs met criteria. We found relevant COS for 36 of 67 SRs (54%). Our framework for comparing the scope of a SR and a COS describes 16 scenarios arising when the breadth of the populations and the interventions are considered. The framework guides systematic reviewers to determine whether a COS is very likely to be relevant, may be relevant, or unlikely to be relevant. Sixty-two percent of outcomes in COS (interquartile range, 40% - 80%) were either specific or general matches to outcomes in SRs.

We found a COS with relevant scope for more than half of the SRs in our sample, with almost two-thirds of the recommended core outcomes matched to outcomes chosen for the SRs. Consideration of COS appears relevant for SR planning and our framework for assessing relevance of a given COS may help with this process.