Shahroud University of Medical siences Shahroud Journal of Medical Sciences 2423-6594 12 4 2026 08 09 Evaluating the Therapeutic Potential of the Biologically Active Form of Vitamin D in the Management of Acute Renal Failure: A Randomized Single-Blind Clinical Trial 44 50 eng Asiye Ommat Mohamadi Department of Internal Medicine, Nohom Day Hospital, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran.. asyomat@gmail.com Mostafa Enayatrad Clinical Research Development Unit, Bahar Hospital, Shahroud University of Medical Sciences, Shahroud, Iran.. mostafaenayatrad@gmaail.com Amirhessam Kheirieh Clinical Research Development Unit, Bahar Hospital, Shahroud University of Medical Sciences, Shahroud, Iran.. a.h.kheirieh7@outlook.com Sepideh Mahdavi Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.. s.mahdavi88@gmail.com Monireh Amerian School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran.. crdu.bahar@gmail.com 2025 06 09 2025 12 20 Background: This study was designed to evaluate the impact of the active form of vitamin D on the progression of Acute Renal Failure (ARF) and the improvement of renal function markers. Methods: This single-center, randomized, parallel-group clinical trial was conducted in adult patients (>18 years) diagnosed with ARF according to KDIGO criteria. Exclusion criteria included a history of chronic kidney disease, kidney transplantation, primary parathyroid or granulomatous disease, symptomatic nephrolithiasis, pregnancy or breastfeeding, or recent vitamin D supplementation. Participants in the intervention group received oral active vitamin D (1,25-dihydroxy-vitamin D) at a dose of 0.25 mg once daily, whereas the control group received routine care for ARF. Treatment continued for up to three months or until recovery. Analyses followed the intention-to-treat principle. Continuous variables were analyzed using repeated measures ANOVA, and categorical variables were compared using chi-square or Student’s t-tests, with statistical significance set at P-value<0.05. Results: Repeated measures showed a significant decrease in mean urea levels within each group over time (P-value=0.006), but no significant difference was found between groups (P-value=0.342). Similarly, creatinine levels decreased in both groups, but differences between groups were not statistically significant (P-value=0.511). Conclusions: The study found no strong evidence that oral active vitamin D improves recovery compared with routine treatment alone in patients with ARF. Larger trials with higher doses and longer follow-up are needed to determine whether vitamin D supplementation could be beneficial.