Antidiabetogenic effects of hydroxychloroquine on insulin sensitivity and beta cell function: a randomised trial

Aims/hypothesis Hydroxychloroquine (HCQ), an antimalarial drug with anti-inflammatory properties, is employed in rheumatic diseases. In observational studies, patients with rheumatic diseases treated with HCQ have a lower risk of developing diabetes. However, the physiological mechanisms remain unexplained. We hypothesised that HCQ may have favourable effects on insulin sensitivity and/or beta cell function. Methods This was a randomised, double-blind, parallel-arm (placebo vs HCQ 400 mg/day) trial at the University of Pittsburgh. Randomisation was conducted by a computer system with concealment by sealed envelopes. Treatment duration was 13 ± 1 weeks. Randomised participants (HCQ n = 17; placebo n = 15) were non-diabetic volunteers, age >18, overweight or obese, with one or more markers of insulin resistance. All participants were included in intention-to-treat analysis. Outcomes were changes in insulin sensitivity and beta cell function measured by intravenous glucose tolerance tests and minimal model analysis. Results There was a positive change in insulin sensitivity with HCQ but not placebo (mean ± SEM: +20.0% ± 7.1% vs −18.4% ± 7.9%, respectively; p