Antidiabetic effects of hydroxychloroquine in two Japanese patients with systemic lupus erythematosus

Hydroxychloroquine (HCQ), an antimalarial drug, is recommended for all patients with systemic lupus erythematosus (SLE), and is widely used around the world. HCQ has various beneficial effects, including antidiabetic effects but was unavailable in Japan until gaining approval for SLE treatment in 2015. We present herein the cases of two Japanese women with SLE and diabetes mellitus (DM) who were treated using HCQ and achieved reductions in glycosylated hemoglobin (HbA1c). A 48 year-old Japanese woman with SLE and DM (patient 1) received oral HCQ at 200 mg/day for the treatment of lupus nephritis. HbA1c levels decreased from 7.2–6.2% after 14 months of HCQ without any loss of body weight or alterations in doses of glucocorticoid or hypoglycemic agents. A 64 year-old Japanese woman with SLE and DM (patient 2) received oral HCQ at 200 mg and 400 mg on alternate days for the treatment of erythema. She also received intensive insulin therapy. HCQ drastically reduced both HbA1c levels, from 10.3 to 7.5%, and the insulin doses required without altering the doses of glucocorticoid or hypoglycemic agents, although body weight increased slightly. No episodes of hypoglycemia were seen in either patient. HCQ can achieve antidiabetic effects in Japanese SLE patients.