Outcome domains, outcome measures and characteristics of randomized controlled trials testing non-surgical interventions for osteoarthritis.

OBJECTIVE: Core outcome set (COS) is the minimum set of outcome domains that should be measured and reported in clinical trials. We analyzed outcome domains, prevalence of use of COS published by Outcome Measures in Rheumatology (OMERACT) initiative, outcome measures for outcome domains recommended by OMERACT COS, duration and size of randomized controlled trials (RCTs) testing non-surgical interventions for OA.

METHODS: We searched PubMed and analyzed RCTs about non-surgical interventions for OA published from June 2012 to June 2017. We extracted data about trial type, use of OMERACT COS, efficacy outcome domains, safety outcome domains, outcome measures used for COS assessment, duration and sample size.

RESULTS: Among 334 analyzed trials, complete OMERACT-recommended COS was used by 14% of trials. Higher median prevalence of using OMERACT COS was found in trials explicitly described as Phase III, and trials of pharmacological interventions with follow up ≥ 1 year, but both with wide range of COS usage. Trialists used numerous different outcome measures for analyzing core outcome domains: 50 different outcome measures for pain, 74 for physical function, 9 for patient global assessment and 5 for imaging.

CONCLUSION: Suboptimal use of recommended COS and heterogeneity of outcome measures is reducing quality and comparability of OA trials and hinders conclusions about efficacy and comparative efficacy of non-surgical interventions. Interventions for improving study design of trials in this field would be beneficial.