Calcifediol Rather Than Cholecalciferol for a Patient Submitted to Malabsortive Bariatric Surgery: A Case Report

Vitamin D deficiency following malabsorptive bariatric surgery can lead to osteomalacia. We report a patient with severe vitamin D deficiency following malabsorptive bariatric surgery successfully treated with calcifediol but not cholecalciferol. A 40-year-old woman, submitted to biliopancreatic diversion 20 years before and chronically treated with 50,000 IU cholecalciferol weekly, was admitted to our Endocrine Unit because of severe lower back pain, muscle weakness, and generalized muscular hypotrophy, associated with hypocalcemia and elevated PTH levels. Initial evaluation revealed low serum albumin, low albumin-corrected serum calcium (7.36 mg/dL), high serum PTH (240 pg/mL), bone-specific alkaline phosphatase (125 μg/L) and 1,25-dihydroxyvitamin D (112 pg/mL) concentrations, undetectable serum 25-hydroxyvitamin D (<7 ng/mL), and evidence of reduced liver function. Bone mineral density was markedly low. Normocalcemia was initially restored with intravenous albumin and calcium gluconate. Treatment with calcitriol (0.5 μg three times daily) and oral calcium carbonate (1000 mg daily) was simultaneously started and cholecalciferol was replaced with calcifediol [125 μg (5000 IU) daily)]. During follow-up the calcifediol dose was progressively tapered to 25 μg (1000 IU) daily and the calcitriol dose was progressively reduced and finally withdrawn. Serum albumin and other biochemical parameters normalized, bone mineral density significantly increased, and the patient's clinical conditions progressively improved, with a substantial recovery of autonomy. Serum vitamin D binding protein at the last observation was in the normal range. Our data suggest that calcifediol might be more efficacious than cholecalciferol for prevention and treatment of vitamin D deficiency in patients treated by malabsorptive bariatric surgery.