Effect of hydroxychloroquine on insulin sensitivity and lipid parameters in rheumatoid arthritis patients without diabetes mellitus: a randomized, blinded crossover trial.

OBJECTIVE: Observational studies suggest that hydroxychloroquine (HCQ) may reduce the risk of developing diabetes mellitus in patients with rheumatoid arthritis (RA). We examined the effect of HCQ on insulin resistance in subjects without diabetes mellitus with stable RA. METHODS: Twenty-three RA subjects not currently using HCQ completed a 16-week, double-blind crossover study. Subjects were randomly allocated to receive HCQ (6.5 mg/kg/day) or placebo for the first 8 weeks, followed by crossover to the other arm for the final 8 weeks. Subjects underwent oral glucose tolerance testing and fasting lipid measurements at baseline, 8 weeks, and 16 weeks. The change ± SD from baseline in insulin sensitivity index (ISI), homeostatic model assessment for insulin resistance (HOMA-IR), and lipid parameters were compared between placebo and HCQ using linear regression. RESULTS: The mean patient age was 56 years, with 96% women, and the median body mass index was 26.0 kg/m2. After 8 weeks of HCQ, the mean ± SD ISI increase was 0.4 ± 2.9 compared with a small increase during placebo of 0.14 ± 3.1 (adjusted P = 0.785), and the mean ± SD HOMA-IR decrease was 0.3 ± 1.5 during HCQ versus a decrease of 0.42 ± 1.4 during placebo (adjusted P = 0.308). Small decreases in total cholesterol (12.7 mg/dl) and low-density lipoprotein (LDL) cholesterol (12.4 mg/dl) were observed during the HCQ treatment periods (both adjusted P < 0.05 compared to placebo). CONCLUSION: HCQ use for 8 weeks in patients without diabetes mellitus with stable RA produced no significant change in insulin resistance. We observed small and statistically significant improvements in total and LDL cholesterol during HCQ treatment.

Hydroxychloroquine improves insulin sensitivity in obese non-diabetic individuals.

INTRODUCTION: Hydroxychloroquine (HCQ) is a common disease modifying therapy for the treatment of rheumatoid arthritis (RA). Prior research suggests that HCQ may reduce the risk of diabetes mellitus in patients with RA. To investigate the mechanism of this effect, we examined the effect of HCQ on insulin resistance, insulin sensitivity, and pancreatic ß-cell secretion of insulin in non-diabetic, obese subjects. METHODS: We recruited 13 obese, non-diabetic subjects without systemic inflammatory conditions for an open-label longitudinal study of HCQ 6.5 mg per kilogram per day for six weeks. Subjects underwent an oral glucose tolerance test at three time points: 0 weeks (pre-treatment with HCQ), 6 weeks (at the end of the HCQ treatment), and 12 weeks (6 weeks post HCQ-treatment). The Matsuda Insulin Sensitivity Index (ISI), HOMA-IR, and HOMA-B were compared across time-points. RESULTS: The mean age of the cohort was 49 years, 77% females and median body mass index was 36.1 kg/m2. After 6 weeks of HCQ therapy, ISI increased from a median (interquartile range) of 4.5 (2.3-7.8) to 8.9 (3.7-11.4) with a p-value of 0.040, and HOMA-IR decreased from a median of 2.1 (1.6-5.4) to 1.8 (1.02-2.1) with a p-value of 0.09. All these variables returned toward baseline at week 12. CONCLUSION: HCQ use for 6 weeks in non diabetic obese subjects was associated with a significant increase in ISI and trends toward reduced insulin resistance and insulin secretion. These data suggest that HCQ, a common medication used to treat RA, possesses beneficial effects upon insulin sensitization. Further study of the insulin sensitizing effects of HCQ in patients with RA is warranted.