Compliance and persistence with hydroxychloroquine in South Korean patients with systemic lupus erythematosus

We aimed to analyze compliance and persistence with hydroxychloroquine (HCQ) in real practice and identify risk factors for poor adherence in South Korean patients with systemic lupus erythematosus (SLE). This retrospective longitudinal study evaluated 235 SLE patients in whom oral HCQ was newly started from 2002 to 2016 at a tertiary hospital in South Korea. Compliance was assessed using one-year medication possession ratio (MPR) and non-compliance was defined as a one-year MPR < 0.8. Persistence was determined as the time from HCQ treatment initiation to discontinuation without interruption for ≥56 days. The mean one-year MPR of HCQ was 0.88 and the frequency of non-compliance was 19.9%. During the study period, 115 (48.9%) patients discontinued HCQ and forgetfulness and/or carelessness (73%) were the most common reason for HCQ non-persistence, followed by adverse events (10.4%), unknown factors (10.4%), and pregnancy (6.1%). Median duration until HCQ discontinuation was 55.1 months and the one-year persistence rate to HCQ was 0.8. SLE Disease Activity Index 2000 (SLEDAI-2K)  < 6 was a significant risk factor for non-compliance (OR = 2.98, p = 0.001) and non-persistence (HR = 1.55, p = 0.046) with HCQ after adjusting confounding factors. However, HCQ adherence was not associated with the dose of HCQ or concomitant immunosuppressive medications. Our data showed that overall adherence to HCQ in SLE patients was suboptimal in real practice and SLEDAI-2K score  < 6 was a risk factor for poor adherence, suggesting the need to improve adherence with HCQ treatment in SLE patients, especially in those with low disease activity.