Effect of Single-Dose Oral Vitamin D (200,000 IU) for the Treatment of Painful Diabetic Neuropathy

Objective: To assess the effect of a single-dose, oral vitamin D supplementation (soft gel capsule of 200,000 IU) in subjects with painful diabetic neuropathy (PDN) in Pakistan. Design: Randomized control trial. Materials and Methods: This randomized control trial was conducted at the Baqai Institute of Diabetology and Endocrinology (BIDE), Pakistan from November 2021 to August 2022. Subjects with diabetes without any signs of vitamin D deficiency were included. Baseline details were obtained by a predesigned questionnaire. Douleur neuropathy 4 (DN4) score was used for diagnosing PDN. Biochemical tests include serum 25-hydroxyvitamin D (OH)D and HbA1c for screening at baseline and at 3 months follow-up were analyzed. Subjects were categorized into two: a control group and an intervention group. The intervention group was given a single soft gel vitamin D capsule (200,000 IU) after screening by expert paramedical staff. Based on baseline serum vitamin D levels, the intervention group was further categorized into insufficient vs. deficient groups, and the control group was categorized into insufficient vs. sufficient. Results: Of 159 participants, 19.5% vs. 44.7% subjects were with insufficient vs. deficient vitamin D levels in the intervention group, and 10.7% vs. 25.1% were with insufficient vs. sufficient vitamin D levels in the control group, respectively. Though the findings are insignificant, DN4 score at follow-up in intervention groups and control groups was reduced compared to the baseline DN4 score. Furthermore, we observed a reduction in post-HbA1c levels in both the intervention groups (insufficient vs. deficient) and the control-sufficient group. Conclusion: Treatment with vitamin D supplementation in people with PDN helps to improve vitamin D levels, DN4 score, and HbA1c levels, though dose-response is yet to be compared.