No Benefit for Two Supplements on Renal Function in Patients with Diabetes

Vitamin D and ω-3 fatty acid supplementation have been proposed as biologically plausible interventions to slow decline in renal function among patients with type 2 diabetes. In this randomized trial, about 1300 people with type 2 diabetes (mean age, 68) received supplementation with ω-3 fatty acids, vitamin D₃ (2000 IU/day), both, or placebo. Patients had no known cardiovascular disease or cancer; most were taking medications for hypertension and diabetes. This analysis was a substudy from the large VITAL trial (NEJM JW Gen Med Dec 15 2018 and N Engl J Med 2019; 380:33; NEJM JW Gen Med Dec 15 2018 and N Engl J Med 2019; 380:23).

Mean renal function, measured by estimated glomerular filtration rate (eGFR), was 86 mL/minute/1.73 m² at baselin…