A randomized controlled clinical trial comparing calcitriol versus cholecalciferol supplementation to reduce insulin resistance in patients with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in the world with no definite treatment. Insulin resistance (IR) and low serum vitamin D are closely linked to NAFLD. Since there is no comparative study on the effect of calcitriol with cholecalciferol on NAFLD based on homeostasis model of insulin resistance (HOMA-IR) as an IR indicator, so we designed this research.A double blind randomized clinical trial was conducted on patients with NAFLD with concomitant vitamin D deficiency/insufficiency at two referral tertiary teaching medical centers, from July 2017 to January 2019. Patients were randomly divided into two groups: calcitriol (1 mcg/day) and cholecalciferol (50,000 IU/week) for 8 weeks. Before and after the intervention, anthropometric and laboratory data were measured and HOMA-IR was calculated for each patient.54 patients completed the trial. In total, calcitriol supplementation improved serum insulin levels as well as IR based on the HOMA-IR index, significantly compared to the cholecalciferol group. HOMA-IR decreased 1.8 times more in patients receiving calcitriol than in those receiving cholecalciferol, which was clinically meaningful. The observed changes were more pronounced in patients with higher baseline body mass index. Moreover, calcitriol was more associated with a significant decrease in liver enzymes and cholesterol levels comparing to cholecalciferol.Based on the findings of this study, the use of calcitriol supplementation significantly reduced HOMA-IR as an IR indicator in NAFLD patients, compared to cholecalciferol. To confirm this findings, further studies with larger sample sizes are recommended.