Temporal and regional variation in the use of biologic and targeted synthetic DMARDs for rheumatoid arthritis: a nationwide cohort study.

Objective: To evaluate temporal and regional variation in biologic and targeted synthetic DMARD (b/tsDMARD) initiation for rheumatoid arthritis (RA) in England and Wales.

Methods: An observational cohort study was conducted for people with RA enrolled in the National Early Inflammatory Arthritis Audit (NEIAA) between May 2018 and April 2022 who had 12-month follow-up data. Temporal trends in escalation to b/tsDMARDs within 12 months of initial rheumatology assessment were explored, including comparisons before and after publication (July 2021) of national guidelines that lowered the threshold for b/tsDMARD initiation to include moderate-severity RA. Case-mix-adjusted, mixed-effects regression was used to evaluate regional and hospital-level variation in b/tsDMARD initiation.

Results: Of 6,098 RA patients with available follow-up, 508 (8.3%) initiated b/tsDMARDs within 12 months of initial assessment. b/tsDMARD escalation increased marginally towards the end of the study period (9.2% in May 2021/22); however, no significant differences were evident after guidelines were published permitting b/tsDMARDs for moderate-severity RA. The proportion of individuals escalated to b/tsDMARDs varied considerably between regions, ranging from 5.1% in Wales to 10.7% in North-West England. Following case-mix adjustment, the intraclass correlation (ICC) for hospitals within regions was 0.17, compared with a between-region ICC of 0.0, suggesting that the observable regional variation reflected hospital-level differences rather than systematic differences between regions themselves.

Conclusion: There is marked variation in escalation to b/tsDMARDs for people newly-diagnosed with RA throughout England and Wales, despite a universal healthcare system. These disparities must be addressed if we are to deliver equitable access to b/tsDMARDs, regardless of geography.