Serum Parathyroid Hormone and 25-Hydroxyvitamin D Concentrations Before and After Biliopancreatic Diversion.

Abstract

Biliopancreatic diversion with duodenal switch (BPD-DS) decreases vitamin D and calcium absorption, which may result in secondary hyperparathyroidism. This study aimed at evaluating the prevalence of vitamin D deficiency and secondary hyperparathyroidism before and after BPD-DS. A retrospective analysis of patients who had undergone BPD-DS at a tertiary bariatric center between 2003 and 2010 and for whom simultaneous measurements of serum 25-hydroxyvitamin D and parathyroid hormone were available within 5years post-op was performed. The prevalence of vitamin D deficiency (< 20ng/ml) and secondary hyperparathyroidism (> 65pg/mL) at different time points was calculated. Included were 1436 patients (mean ± SD, age 42.7 ± 10.4years; BMI 51.5 ± 8.6kg/m2; 69.8% women). Prevalence of vitamin D deficiency decreased up to 6-12months after surgery (from 35.8% at baseline down to 6-9%) then rose progressively, plateauing at 15.5% after 36months. Prevalence of hyperparathyroidism was 28.5% before surgery and rose progressively after surgery, reaching 68.6% at 5years. Mean serum corrected calcium increased from 0 to 6months then decreased up to 36months. Preoperatively, the prevalence of hypocalcemia was 7.3%. It increased after 12months, attaining 26.9% at 48months. Prevalence of vitamin D deficiency and secondary hyperparathyroidism is high before BPD-DS. Despite a low prevalence of vitamin D deficiency after surgery, prevalence of hyperparathyroidism increased steadily 1year after surgery, preceded by a decrease in serum calcium. Factors explaining the high prevalence of secondary hyperparathyroidism after BPD-DS and its long-term impact on bone health should be addressed.