Medication Persistence of Disease-Modifying Antirheumatic Drugs and Anti-Tumor Necrosis Factor Agents in a Cohort of Patients With Rheumatoid Arthritis in Brazil.

OBJECTIVE: To assess the use and persistence of anti-tumor necrosis factor (anti-TNF) versus disease-modifying antirheumatic drug (DMARD) therapies in patients with rheumatoid arthritis (RA) in Brazil.
METHODS: This was a new-user cohort study of RA patients from 2003 to 2010, using administrative data. Individuals were classified as being persistent using a drug at the first year and the first 2 years after cohort entry, if they did not discontinue that drug during that period. Cox regression was used to identify potential determinants of discontinuation of therapy in each medication group.
RESULTS: Among 76,351 patients, 14,313 were using anti-TNF (+/- DMARD) therapy. At the end of the first year of followup, 48.2% continued using anti-TNF (+/- DMARD) therapy compared to 42.6% who persisted with DMARDs only. At the end of the second year, 23.1% of anti-TNF (+/- DMARD) users and 19.3% of DMARD-only users continued with therapy. Infliximab users had the lowest persistence rates. Multivariate Cox regression analysis showed that among anti-TNF (+/- DMARD) users, higher discontinuation rates were observed in female patients, in patients with lower income (only at the first 2 years of followup), in nonresidents of the region with the highest Human Development Index (HDI) rates, in those with a higher comorbidity score, and in those enrolled in the 2003-2006 period. Among DMARD-only users, younger patients, patients with lower income, nonresidents in regions with high HDI, those with a higher comorbidity score, and those enrolled in the 2003-2006 period were also more likely to discontinue therapy.
CONCLUSION: Brazilian patients with RA showed low rates of medication persistence for DMARDs and anti-TNF agents, particularly at the first 2 years of followup. Future work could determine what other factors might contribute to drug persistence in RA.