Background/Purpose: The development of biologic and targeted synthetic (b/ts)DMARDs contributed to improved treatment outcomes in rheumatoid arthritis (RA). However, high medication costs may limit their use. Previously we showed less b/tsDMARD use in countries with a lower socioeconomic status (SES), than in countries with higher SES. Here we take a more detailed look at b/tsDMARD use across countries and explore cross-country relationships between Gross Domestic Product (GDP)-per-capita, indicators of b/tsDMARD use and disease outcomes in RA-patients

Methods: This multinational, observational study included countries contributing ≥100 patients using b/tsDMARDs, with available follow-up, to one of two registries: METEOR, an international registry capturing daily practice data of patients with a clinical diagnosis of RA, and JAK-POT, an investigator-initiated collaboration between national registries aiming to evaluate clinical aspects of b/tsDMARDs in RA. On a per-country basis, mean DAS28 was calculated from the last available follow-up visit per patient. B/tsDMARD usage was determined as mean time to start b/tsDMARD therapy since date of diagnosis, number of b/tsDMARDs tried per patient and duration of b/tsDMARD therapy. To calculate the time to start a first b/tsDMARD per country included from JAK-POT, only bionaïve patients were included. Possible associations between GDP per capita, indicators of b/tsDMARD use and DAS28 were tested using univariable linear regression. Regression coefficients (β) are interpreted as the numerical increase in the outcome per one point increase in the predictor.

Results: Data from 25,832 patients from 17 different countries showed varying b/tsDMARD prescriptions. GDP-per-capita ranged from 6505 (India) to 93350 Intl$ (Ireland). Time to start b/tsDMARD therapy ranged from 0.5(Austria) to 11.1 (Finland) years. Mean number of b/tsDMARDs tried per patient ranged from 1.0 (Turkey) to 2.4 (Switzerland). Duration of b/tsDMARD therapy ranged from 0.9 (India) to 5.5 (Portugal) years (fig 1). Baseline DAS28 ranged between 3.7 and 6.1, but was not related to any of the indicators of b/tsDMARD use: time to start a b/tsDMARD β 0.08 (95% CI -0.7; 0.9), number of prescribed b/tsDMARDs β 0.06 (95% CI -0.03; 0.2), duration of b/tsDMARD treatment β 0.1 (95% CI -0.3; 0.5).No statistically significant associations were observed between GDP-per-capita and time to start b/tsDMARD therapy (fig 1A, β 0.09 CI 95% -0.7; 0.9), number of b/tsDMARDs tried per patient (fig 1B, β 0.07 CI 95% -0.02; 0.2) or duration of b/tsDMARD therapy (fig 1C, β 0.1 CI 95% -0.3; 0.5). None of the indicators of b/tsDMARD prescription were significantly related to DAS28 at the end of follow up: time to start a b/tsDMARD β 0.02 (95% CI -0.05; 0.1), duration of b/tsDMARD therapy β -0.03 (95% CI -0.2; 0.1) and number of b/tsDMARDsβ -0.03 (95% CI -0.6; 0.6).

Conclusion: This study showed varying b/tsDMARD prescription behavior and disease activity across 17 countries worldwide. Overall, differences in b/tsDMARD prescription behavior was not related to socioeconomic welfare and disease activity at a country level. This seems to indicate that once patients start a b/tsDMARD, socioeconomic welfare has less impact on b/tsDMARD use.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/cross-country-differences-in-b-tsdmard-prescription-behavior-associations-between-socioeconomics-real-world-b-tsdmard-use-and-disease-outcomes/