Hydroxychloroquine treatment in a community-based cohort of patients with systemic lupus erythematosus

Abstract

Objective: In recent years hydroxychloroquine (HCQ) has emerged as a key therapy in systemic lupus erythematosus (SLE). We determined the rates of HCQ use in a diverse, community-based cohort of patients with SLE and identified predictors of current HCQ use.

Methods: Patients were participants in the University of California San Francisco Lupus Outcomes Study, an ongoing longitudinal study of patients with confirmed SLE. We examined the prevalence of HCQ use per person-year and compared baseline characteristics of users and nonusers, including demographic, socioeconomic, clinical, and health system use variables. Multiple logistic regression with generalized estimating equations was used to evaluate predictors of HCQ use.

Results: A total of 881 patients contributed 3,095 person-years of data over 4 interview cycles. The prevalence of HCQ use was 55 per 100 person-years and was constant throughout the observation period. In multivariate models, the odds of HCQ use were nearly doubled among patients receiving their SLE care from a rheumatologist compared with those identifying generalists or nephrologists as their primary sources of SLE care. In addition, patients with shorter disease duration were more likely to use HCQ, even after adjusting for age and other covariates.

Conclusion: In this community-based cohort of patients, HCQ use was suboptimal. Physician specialty and disease duration were the strongest predictors of HCQ use. Patients who are not using HCQ, those with longer disease duration, and those who see nonrheumatologists for their SLE care should be targeted for quality improvement.

Figure 1. Hydroxychloroquineuse between 2004 and 2007 in the UCSF Lupus Outcomes Study

This chart describes the flow of patients through the 4 waves of interviews with regard to HCQ use. Diagonal lines represent patients who transitioned from one category to the other from one wave to the next. Horizontal lines represent patients who remained in the same category from one wave to the next. Patients who exited the cohort (because of death or loss to follow-up) are counted at the angled line. Sixty eight patients entered the cohort after wave 2.