Effect of Melatonin Supplementation on Glycemic and Lipid Profiles in Kidney Transplant Recipients: A Clinical Trial

Melatonin plays a crucial role in regulating sleep and has potent antioxidant properties. However, the relationship between melatonin supplementation and metabolic factors related to diabetes and lipid profiles-which are associated with increased mortality in kidney transplant recipients has not yet been fully clarified.

This randomized, double-blind, placebo-controlled trial was conducted at Labbafinejad Hospital, Tehran, Iran. Adult kidney transplant recipients (≥6 months post-transplant) received either 6 mg/day melatonin or placebo for three months. A modified intention-to-treat analysis included 42 patients per group. The primary outcomes were changes in fasting blood sugar (FBS) and HbA1c levels, while secondary outcomes included blood pressure and lipid profile parameters. Between-group effects were estimated using linear regression adjusted for baseline values and confounders.

In the melatonin group, FBS decreased by a median of 6.5 mg/dL (P < .001) and HbA1c by 0.25 units (P < .001), whereas both parameters increased in the placebo group. The adjusted between-group effect favored melatonin for HbA1c (β = -0.30%; 95% CI: -0.59 to -0.01; P < .001) but not for FBS (β = -2.61 mg/dL; 95% CI: -17.93 to 12.71; P = .283). Triglyceride levels decreased by 16 mg/dL in the melatonin group compared with an increase of 13.5 mg/dL in the placebo group (adjusted β = -23.77 mg/dL; 95% CI: -45.50 to -2.04; P = .032). No significant differences were observed in blood pressure and renal function.

Melatonin supplementation for three months modestly improved glycemic control and lowered serum triglyceride levels in kidney transplant recipients, with no effects on blood pressure or kidney function. These results support melatonin's potential as an adjunct therapy for metabolic dysregulation in this population, warranting further investigation into its long-term benefits.