Effect of Drug Adherence on Treatment Outcome in Rheumatoid Arthritis

ABSTRACT

OBJECTIVE: The present study aimed to evaluate the effect of drug adherence on treatment outcome in Korean patients with rheumatoid arthritis (RA). METHODS: A total of 2,694 RA patients who had complete data from annual follow-ups over three years in the Korean Observational Study Network for Arthritis were included in this study. Patients were divided into adherent and non-adherent groups according to data for drug adherence over three years. The European League against Rheumatism response and rate of disease flare were compared between two groups over three years. We also compared continuous variables representing treatment outcomes between the two groups. RESULTS: After propensity score matching using a ratio of 13, patients were allocated into non-adherent (n=522) and adherent (n=1,447) groups. The rate of non-response was higher in the non-adherent group over three years; however, there were no significant differences between continuous variables related to treatment outcome between the two groups. To evaluate the difference according to disease duration, patients were classified into early and late RA based on 48-month disease duration. In patients with early RA, the adherent group had lower patient's global health visual analog scale and lower disease activity 28 scores at three years compared with the non-adherence group. In patients with late RA, the non-adherent group had a higher rate of disease flare. CONCLUSION: The adherent group tended to show lower disease activity, especially in early RA, whereas the non-adherence group was associated with non-response and higher risk of disease flare.