Severe obesity and vitamin D deficiency treatment options before bariatric surgery: a randomized clinical trial.

Obesity, which has various complications and co-morbidities, is an epidemic issue worldwide. Vitamin D deficiency (VDD) is a well-known metabolic disorder among patients with severe obesity. While they are good candidates for bariatric surgery, this deficiency can affect the outcome of surgery negatively.The aim of this study was to compare 3 different VDD treatment strategies for use before bariatric surgery and compare serum vitamin D levels after 7 weeks.University hospital, Isfahan, Iran.

This was a single-blinded, randomized clinical trial on 100 patients who were referred for bariatric surgery from 2016 to 2018. Vitamin D (VitD) level was checked before surgery for the patients included in the study, if their VitD level was <30 ng/mL. We rechecked their serum VitD in the 8^th week, after 7 weeks of treatment. The participants were randomly allocated into 3 groups: 33 patients were treated with 50,000 units VitD₃ capsules every week for 7 weeks; 33 patients were treated with a single dose of 300,000 units VitD₃ ampoule; and 34 patients were treated with a combination of a half of the injection dose, followed by the oral capsule for 4 weeks.

No case was lost during the follow-up time. No significant differences were found among the 3 groups in terms of their age (P = .654), body mass index (P = .434), sex (P = .799), initial 25(OH) VitD level (P = .273), and history of supplement use (P = .45). Mean serum VitD levels were 15.21, 13.16, and 13.37 ng/mL, respectively, before the surgery and reached 32.91, 24.74, and 29.49 ng/mL after 7 weeks of treatment in oral, injection, and combined groups, respectively. Finally, the 7-week oral treatment option had significantly higher levels of VitD (P value = .034).

VDD treatment with 50,000 units VitD₃ capsule every week for 7 weeks before bariatric surgery yields a higher level of VitD. Based on our findings, injectable supplements are not recommended for VDD treatment.