Do patients with intersectional disadvantage have poorer outcomes from osteoarthritis management programmes? A tapered-balancing study of patient outcomes from the Good Life with osteoArthritis in Denmark (GLA:D®) programme

Objectives: To investigate whether adults with potential multiple social disadvantage have poorer outcomes following osteoarthritis management programme (OAMP) attendance and if so, what might determine this. Methods: Among consecutive knee OA attenders on the GLA:D® OAMP in Denmark we defined a group with potential ‘intersectional disadvantage’ based on self-reported educational attainment, country of birth, and citizenship. Their outcomes were compared with GLA:D® participants who were native Danish citizens with higher educational attainment. Outcomes were pain intensity, KOOS Quality of Life, and EQ-5D-5L at 3 and 12 months. After data pre-processing, we used entropy balancing to sequentially control for differences between the groups in baseline covariates. Mean between-group differences in outcomes were estimated by weighted linear regression. Results: Of 18,448 eligible participants, 250 (1.4%) were non-native/foreign citizens with lower education. After balancing for differences in baseline score, administrative, and demographic characteristics, they had poorer outcomes than higher educated native Danish citizens on pain intensity and EQ-5D-5L at both follow-up points (e.g. between-group mean differences (95%CI) in pain VAS (0-100) at 3 and 12 months: 3.4 (-0.5, 7.3) and 6.2 (1.7, 10.7) respectively). Differences in KOOS QOL were smaller or absent. Balancing for differences on baseline score, comorbidity, self-efficacy, and depression had the greatest effect on reducing observed outcome inequalities. Conclusion: Outcome inequalities widened following OAMP attendance, particularly at longer-term follow-up but the magnitude of differences was generally modest and inconsistent across outcome measures. Tailoring content to reduce outcome inequalities may be indicated but improving access appears the greater priority.