Alterations in Phosphocalcic Metabolism after Biliopancreatic Diversion

Presentation Number: MON 353
Date of Presentation: April 3rd, 2017

Vanessa Tardio*1, Jean-Philippe Blais2, Pierre Douville3, Stefane Lebel3, Laurent Biertho3, Simon Marceau3, Frédéric-Simon Hould3 and Claudia Gagnon4
1McGill University Health Center, Montreal, QC, Canada, 2CHU de Québec Research Centre, 3Quebec Heart and Lung Institute, 4CHU de Québec Research Centre, Quebec, QC, Canada

Abstract

Bariatric surgery procedures such as the biliopancreatic diversion with duodenal switch (BPD-DS) may lead to the malabsorption of several key nutrients for bone health including vitamin D and calcium. If not appropriately corrected, the secondary hyperparathyroidism that results from vitamin D deficiency and calcium malabsorption will promote bone loss and increase the risk for osteopenia, osteoporosis and fractures. Factors associated with vitamin D deficiency and secondary hyperparathyroidism in BPD-DS patients have not been clearly identified. Our primary aim was to evaluate the prevalence of vitamin D deficiency and secondary hyperparathyroidism in patients who have undergone a BPD-DS procedure at the Quebec Heart and Lung Institute (IUCPQ). Our secondary objectives were (1) to assess whether the prevalence of vitamin D deficiency and secondary hyperparathyroidism varies over time, (2) to identify factors associated with vitamin D deficiency and secondary hyperparathyroidism after BPD-DS, and (3) to examine the prevalence of other nutritional abnormalities associated with bone health. We performed a retrospective analysis of patients who had undergone BPD-DS surgery at IUCPQ between 2003 and 2010. The prevalence of vitamin D deficiency (<50 nmol/L), and hyperparathyroidism (PTH above the upper limit of normal) at the different time-points (0, 3, 6, 12 months and then yearly) during follow-up were calculated. A multivariate logistic regression analysis of the clinical and biochemical factors identified as potentially associated with vitamin D deficiency and secondary hyperparathyroidism was performed on a sub-cohort of 475 patients who had at least 3 follow-up blood tests available. Of 2046 patients who had undergone a BPD-DS procedure at IUCPQ during the study period, 1438 had at least one blood test analyzed at IUCPQ (baseline mean age, 42.6 years; 69.8% women; 35.9% with vitamin D deficiency; 28.4% with hyperparathyroidism). The prevalence of vitamin D deficiency decreased up to 6 months’ post-op (from 35.9% down to 6.3%) then rose progressively after 1 year to plateau at 13% after 36 months. On the contrary, the prevalence of hyperparathyroidism rose after 3 months (from 28.4% to 47.3%), decreased slightly between 6 and 12 months, and then progressively increased up to 5 years (to 68.7%). The baseline characteristics of the sub-cohort of 436 patients were similar to the main cohort. In this single center, retrospective study in patients post BPD-DS, we found a low prevalence of vitamin D deficiency. However, the prevalence of secondary hyperparathyroidism is high, increasing steadily after 1 year postop. We hypothesize that compliance to supplements and/or the use of low-dose calcium carbonate in a population where calcium citrate is usually recommended may explain these results.

 

Nothing to Disclose: VT, JPB, PD, SL, LB, SM, FSH, CG