34 Evaluation of adverse events and relapse risk of systemic lupus erythematosus during treatment with hydroxychloroquine

Background The antimalarial drug hydroxychloroquine (HCQ) has been widely used in the world to control the disease activity of systemic lupus erythematosus(SLE). In Japan, it has not been approved until September 2015 due to the problem of retinopathy induced by chloroquine. For these reasons, there is insufficient evidence for its effects and adverse events. Here, we evaluated adverse events and relapse risk of SLE during the treatment of HCQ. Methods We conducted an analysis of retrospectively collected data of 109 patients who were diagnosed as SLE and treated with HCQ at least 12 months at Nagasaki University Hospital and community hospitals. Demographic data included the patient‘s age at the onset of SLE, gender, the disease duration of SLE (the time from the diagnosis of SLE until the renal biopsy), comorbidities of Sjogren syndrome (SS)/anti-phospholipid syndrome (APS), and the treatment for induction. We identified the risk of adverse events and relapse at 12 months after introduction of HCQ. Results Most of the patients were female (88.1%). The median age at introduction of HCQ was 40.0 years (interquartile range [IQR] 30.550.0 years), and the disease duration of SLE was 95 months (IQR 38.0184.5 months). The mean observation period after HCQ introduction was 12 months. The comorbidity rates of SS and APS were 25.7% and 20.2%, respectively. The SELENA-SLEDAI decreased significantly after 3 months of introduction. The dose of oral prednisolone also decreased significantly after 6 months of introduction. Eighty-six cases (78.9%) continued HCQ at 12 months after introduction. The adverse events appeared in 27 cases (24.8%), including 11 cases of skin rashes (10.1%) and 6 cases of gastrointestinal symptoms (5.5%). Predictive factor for adverse event was white blood cell (WBC) counts at baseline (odds ratio: 0.9997, 95% CI: 0.9994–0.9999, p=0.0285). Twelve of 86 cases (14.0%) experienced relapse those who needs to start prednisolone/immunosuppressants or increase the dose of prednisolone. The multivariate analysis revealed C4 value at baseline was the predictive factor of relapse (odds ratio: 0.841, 95% CI: 0.718–0.984, p=0.0097). Conclusions We retrospectively analyzed the risk of adverse events and relapse after HCQ introduction with a mean 12 month follow-up in SLE. The lower value of C4 at HCQ introduction was a predictive factor for relapse and the lower counts of WBC was a predictive factor for adverse event. Funding Source(s): N/A