Nationwide patterns of hydroxychloroquine dosing and monitoring of retinal toxicity in patients with systemic lupus erythematosus

This study identified trends in hydroxychloroquine (HCQ) prescription and retinopathy screening in patients with systemic lupus erythematosus (SLE) according to clinical practice guidelines to minimise the risk of HCQ retinopathy. We used data from patients diagnosed with SLE between 2004 and 2019 from the National Health Insurance Service in Korea. To assess trends of daily dose per actual body weight (ABW), we performed an interrupted time-series analysis and identified effects after revision of guidelines. Among 38,973 patients with SLE, 28,415 (72.9%) were prescribed HCQ from 2004 to 2019. The proportion of patients using HCQ among SLE patients was 63% in 2004 and increased to 76% in 2019. The median daily dose per ABW for HCQ users decreased from 5.88 mg/kg in 2004 to 3.98 mg/kg in 2019, and from 5.45 mg/kg in 2005 to 4.17 mg/kg in 2019 for HCQ new users. The annual implementation rate of screening tests among HCQ new users increased from 3.5% in 2006 to 22.5% in 2019. Study results indicated that HCQ dosing management was adequate based on the revised guidelines. Although the implementation rate of retinal screening has increased, it is necessary to enhance awareness of retinal screening in clinical settings.