Assessing the degree to which randomized controlled trials align with the core outcome set for osteoarthritis of knee and hip: A cross-sectional analysis

To assess the degree of core outcome set alignment and identify issues with alignment to the 2019 COS among clinical trial registrations focused on knee and/or hip osteoarthritis (OA). Our search was performed on registered knee and hip OA randomized controlled trials (RCTs) available on ClinicalTrials.gov and WHO International Clinical Trials Registry Platform. The screening process considered trials registered between 8/2014 and 6/2023. We extracted data on general trial characteristics and the five trial endpoints detailed in the COS (pain, physical function, quality of life, patient global assessment, and adverse events), in a masked and duplicate manner. The frequencies of COS alignment were assessed over time prior to and after COS publication. Of the 10,718 RCTs screened, 481 met inclusion criteria. Most were phase 3 (368/481, 76.51%) and heavily university-funded (184/481, 38.25%). Despite the 2019 COS, no marked enhancement in overall alignment was noted. The outcome 'Pain' exhibited the highest degree of COS alignment (455/481, 94.59%), whereas 'adverse events' lagged behind (89/481, 18.50%). Additionally, trial factors such as 'Continent', ‘Funding Type’, and ‘Recruitment Status’ displayed no significant influence on COS alignment. Despite the acknowledged advantages of using COS in RCTs and the availability of an updated COS, the alignment to these outcomes remains notably low. Significant efforts are needed to encourage broader adoption in future studies on knee and hip OA, with the aim of improving research quality and patient care.