Used for controlling systemic lupus erythematosus (SLE) flares, hydroxychloroquine has reduced efficacy when doses are limited to 5 mg/kg per day, as recommended in ophthalmology and rheumatology guidelines, a case-crossover study shows. Individualized risks and benefits need to be considered when clinicians choose an optimal hydroxychloroquine dose for people with SLE, the investigators conclude.
The analysis included 168 patients who used hydroxychloroquine during the study period and had at least 1 lupus flare. “There were 308 case periods (mean, 1.8 period per patient), including 141 moderate or severe flare periods, and 420 control periods,” the authors report. “The adjusted OR (AOR) for any lupus flare associated with taking hydroxychloroquine doses of 5 mg/kg per day or less vs more than 5 mg/kg per day was 1.98 (95% CI, 1.03-3.79) and for moderate or severe lupus flares the AOR was 6.04 (95% CI, 1.71-21.30). The corresponding AORs were similar across subgroups but only reached significance for patients with baseline SLEDAI scores of 4 or less (AOR, 2.41 [95% CI, 1.17-4.96]). The smoothed dose OR curve indicated an apparent threshold near 5 mg/kg per day of hydroxychloroquine for an increased risk of flares.”