Severe hypovitaminosis d and secondary hyperparathyroidism in obese subjects submitted to roux-en-Y gastric bypass and biliopancreatic diversion

Introduction: Obese patients submitted to bariatric surgery are at risk of developing nutritional and vitamin deficiencies secondary to malabsorption during follow-up, despite the recommendation of multivitamin supplementation. The aim of our study was to evaluate vitamin D deficiency and secondary hyperparathyroidism in obese subjects after Roux-en-Y gastric bypass or biliopancreatic diversion.Materials and Methods: We studied 161 obese patients, 126 of whom underwent Roux-en-Y gastric bypass and 35 biliopancreatic diversion. We assessed 25-OH-vitamin D, parathyroid hormone, anthropometric parameters (weight, body mass index, waist circumference) and weight loss before and 6, 12 and 24 months after surgery. All patients received multivitamin supplementation.Results: Hypovitaminosis D and hyperparathyroidism were present before and after surgery in both bariatric procedures. No statistically significant difference in vitamin D levels was found between biliopancreatic diversion and Roux-en-Y gastric bypass. Increased parathyroid hormone levels were statistically significant 24 months after Roux-en-Y gastric bypass compared to baseline (p=0.0005).Conclusions: Measurement of serum calcium, vitamin D and parathyroid hormone should be performed in obese patients who undergo bariatric surgery. The presence of secondary hyperparathyroidism in 36% of our patients after 24 months confirms the need for aggressive supplementation with calcium and vitamin D.