Effects of Laparoscopic Sleeve Gastrectomy on Parathyroid Hormone, Vitamin D, Calcium, Phosphorus, and Albumin Levels

Abstract

Background: Laparoscopic sleeve gastrectomy (LSG) reduces obesity-related co-morbidities, such as diabetes, hypertension, and hyperlipidemia. Endocrinological abnormalities may occur as undesired side effects. Most centers routinely prescribe folic acid, cyanocobalamin (vitB12), and protein replacement in the postoperative period, but 25-OH-vitamin-D3 (vitD) and intact parathyroid hormone (iPTH) levels are not routinely followed up. The aim of this study was to identify the effects of LSG on iPTH, vitD, calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), and albumin levels.

Methods: Data of morbidly obese patients who underwent LSG between January and December 2014 were studied in this prospectively designed study. Serum levels of iPTH, vitD, Ca, P, folic acid, vitB12, ALP, and albumin were measured preoperatively and postoperatively at the 3rd, 6th, and 12th months.

Results: In total, 119 patients were analyzed. All patients had normal iPTH, vitD, Ca, P, folic acid, vitB12, ALP, and albumin values preoperatively, and 31.6% had received vitD supplementation during their nutritionist observation time before surgery. At the 3rd, 6th, and 12th postoperative months, 21 (17.6%), 17 (17.3%), and 1 (0.8%) patients, respectively, had increased iPTH and ALP and decreased vitD levels. A total of 39 (32.7%) patients needed high-dose vitD treatment during a 1 year follow-up. Approximately 37.5% of the patients who received vitD supplementation preoperatively needed vitD supplementation postoperatively. Hospital records of 101 of 119 patients who underwent LSG could be screened to determine their vitD supplementation requirements previously ordered by their nutritionist for a 1-year period before LSG. Thirty-two (31.6%) of the 101 patients had received vitD supplementation during the 1-year period preoperatively.

Conclusions: Although serum levels of iPTH, vitD, Ca, P, vitB12, ALP, and albumin may be normal preoperatively, severe vitD insufficiency requiring high-dose vitD replacement may develop in morbidly obese patients postoperatively. Instead of iPTH and vitD, which are expensive to measure, ALP serum level, which is correlated with iPTH levels, can be a good indicator to monitor calcium metabolism.

Keywords: Alkaline phosphatase; Metabolic disorders; Morbid obesity; Sleeve gastrectomy; Vitamin D.