Objective: To investigate globally the ratio between biological and targeted synthetic disease-modifying anti-rheumatic drugs (btsDMARDs) and glucocorticoid (GC) use in patients with rheumatoid arthritis (RA), in relation to country-level socioeconomic status (SES).
Method: Data on btsDMARD and GC use between 1 January 2007 and 13 September 2021 were extracted from the international observational METEOR RA registry. The ratio between the proportion of patients who had ever used a btsDMARD and those who had ever used a GC and never a btsDMARD, during 2 years of follow-up, was calculated per country. Associations between the btsDMARD/GC ratios and country-level indicators of SES were assessed with linear regression.
Results: Data from 10 856 patients covering eight geographically spread countries, of whom 8484 were from India, showed a wide range of drug use during 2 years of follow-up: btsDMARD (with or without GC), from 1% (South Africa, India) to 26% (Massachusetts, USA); GC and never btsDMARD use, 19% (UK) to 92% (South Africa). Higher country-level SES was related to a higher btsDMARD/GC ratio. For every additional 10 000 International $, GDP per capita, household net adjusted disposable income, and health expenditure per capita, the estimated increase in btsDMARD/GC ratio (range 0-1) was 0.1 (95% CI 0.05;0.1), 0.2 (95% CI 0.08;0.3), and 0.6 (95% CI 0.4;0.8), respectively.
Conclusion: In this analysis based on eight different countries, we show that the btsDMARD/GC ratio varies widely across countries. This was strongly associated with general country-level indicators of level of wealth, i.e. greater wealth was associated with a higher ratio.