Parenteral vitamin D supplementation is superior to oral in vitamin D insufficient patients with type 2 diabetes mellitus.

BACKGROUND/OBJECTIVES: Oral vitamin D supplementation is better than parenteral in improving vitamin D deficiency in individuals with no systemic illness. Our aim was to compare the efficacy of oral and parenteral routes of vitamin D supplementation on circulating serum 25(OH) vitamin D level in patients with type 2 diabetes mellitus.

METHODS: Total 85 cases of with type 2 diabetes mellitus were screened for vitamin D status of which 71 patients were vitamin D insufficient/deficient. They were randomized into two intent to treat groups with different vitamin D supplementation protocols (a) Oral-60000 IU per day for 5days (group I; n=40) and (b) injectable-300000 IU intramuscularly once (group II; n=31). Baseline and one month post supplementation 25(OH) vitamin D levels were measured in both the groups.

RESULTS: Baseline clinical characteristics and 25(OH) vitamin D levels were comparable in both the groups. Post treatment 25(OH) vitamin D level in group I was 26.06±9.06ng/ml and in group II was 49.69±18.92ng/ml. After one month of vitamin D supplementation, increment in 25(OH) vitamin D level from baseline was significantly higher in group II than group I (p<0.001).

INTERPRETATION & CONCLUSIONS: Injectable method of supplementation was better than oral route in improving serum 25 (OH) vitamin D status in patients with type 2 diabetes. The study suggested impaired absorption of vitamin D from the gastrointestinal tract in patients with type 2 diabetes mellitus and a need for parenteral route of vitamin D supplementation in deficient patients with type 2 diabetes mellitus.