Hydroxychloroquine may be associated with reduced risk of coronary artery diseases in patients with rheumatoid arthritis: A nationwide population-based cohort study.

OBJECTIVES: The aim of this study was to determine whether hydroxychloroquine (HCQ) usage is associated with incidental risk of coronary artery diseases (CAD) in patients with rheumatoid arthritis (RA).

METHODS: The Longitudinal Health Insurance Database in Taiwan was used. The study cohort comprised of 1104 newly diagnosed RA patients between 2001-2010, and patients were followed until 31 December 2011. Patients with history of CAD before RA diagnosis were excluded. We define as HCQ users if the usage duration of HCQ>180 days and non-users if less than 90 days. After propensity score matching of age, sex, index date and comorbidities, the study cohort was comprised of 346 patients: 173 HCQ users and 173 non-users. The study outcome was incidence of CAD. Cox regression model was used to estimate the hazard ratio (HR) of disease after controlling for demographic, other comorbidities and drugs. We also evaluate the effects of HCQ use and CAD events on different characteristics of RA patients.

RESULTS: Kaplan-Meier curves comparing the HCQ users and non-users revealed a statistical significant difference (P value of log-rank test <.001). The adjusted HR for HCQ users versus non-users for CAD events was 0.32 (95% CI, 0.18-0.56, P value <.01) over up to 10 years of follow-up. The adjusted HR (95% CI) of CAD for different age group, gender and other subgroups showed no effect of interaction among each subgroup analysis parameter.

CONCLUSIONS: This study revealed association of decreased CAD risk in RA patients taking HCQ. The protective effect of HCQ on CAD is consistent regarding subgroup analysis on age, gender and different comorbidities groups.