Real-world patient characteristics and use of disease-modifying anti-rheumatic drugs in patients with rheumatoid arthritis: a cross-national study.

Introduction: Rheumatoid arthritis (RA) is associated with significant morbidity and economic burden. This study aimed to compare baseline characteristics and patterns of anti-inflammatory drug use and disease-modifying anti-rheumatic drug (DMARD) use among patients with RA in Southern Italy versus the United States.

Method: Using Caserta Local Health Unit (Italy) and Optum's de-identified Clinformatics® Data Mart (United States) claims databases, patients with ≥ 2 diagnosis codes for RA during the study period (Caserta: 2010-2018; Optum: 2010-2019) were identified. Baseline patient characteristics, as well as proportion of RA patients untreated/treated with NSAIDs/glucocorticoids/conventional DMARDs (csDMARDs)/biological/targeted synthetic DMARDs (b/tsDMARDs) during the first year of follow-up, and the proportion of RA patients with ≥ 1 switch/add-on between the first and the second year of follow-up, were calculated. These analyses were then stratified by age group (< 65; ≥ 65).

Results: A total of 9227 RA patients from Caserta and 195,951 from Optum databases were identified (two-thirds were females). During the first year of follow-up, 45.9% RA patients from Optum versus 79.9% from Caserta were exclusively treated with NSAIDs/glucocorticoids; 17.2% versus 11.3% from Optum and Caserta, respectively, were treated with csDMARDs, mostly methotrexate or hydroxychloroquine in both cohorts. Compared to 0.6% of RA patients from Caserta, 3.2% of the Optum cohort received ≥ 1 b/tsDMARD dispensing. Moreover, 61,655 (33.7%) patients from Optum cohort remained untreated compared to 748 (8.3%) patients from the Caserta cohort. The subgroup analyses stratified by age showed that 42,989 (39.8%) of elderly RA patients were untreated compared to 18,666 (24.9%) young adult RA patients in Optum during the first year of follow-up. Moreover, a higher proportion of young adult RA patients was treated with b/tsDMARDs, with and without csDMARDs, compared to elderly RA patients (Optum: 6.4%; Optum: 1.0%; P-value < 0.001; Caserta: 0.8%; Caserta: 0.1%; P-value < 0.001). Among RA patients untreated during the first year after ID, 41.2% and 48.4% RA patients from Caserta and Optum, respectively, received NSAIDs, glucocorticoids, and cs/b/tsDMARDs within the second year of follow-up. Stratifying the analysis by age groups, 50.6% of untreated young RA patients received study drug dispensing within the second year of follow-up, compared to only 36.7% of elderly RA patients in Optum. Interestingly, more young adult RA patients treated with csDMARDs during the first year after ID received a therapy escalation to b/tsDMARD within the second year after ID in both cohorts, compared to elderly RA patients (Optum: 7.8%; Optum: 1.8%; Caserta: 3.2%; Casert: 0.6%).

Conclusions: Most of RA patients, with heterogeneous baseline characteristics in Optum and Caserta cohorts, were treated with anti-inflammatory/csDMARDs rather than bDMARDs/tsDMARDs during the first year post-diagnosis, especially in elderly RA patients, suggesting a need for better understanding and dealing with barriers in the use of these agents for RA patients. Key Points • Substantial heterogeneity in baseline characteristics and access to bDMARD or tsDMARD drugs between RA patients from the United States and Italy exists. • Most of RA patients seem to be treated with anti-inflammatory/csDMARD drugs rather than bDMARD/tsDMARD drugs during the first year post-diagnosis. • RA treatment escalation is less frequent in old RA patients than in young adult RA patients. • An appropriate use of DMARDs should be considered to achieve RA disease remission or low disease activity.