The Effect of Bariatric Surgery on Calcium Metabolism

INTRODUCTION: Obesity is one of the most important chronic metabolic diseases that includes many comorbidities. Lifestyle changes play the most important role in the treatment of obesity. Despite this, medical treatment and bariatric surgery procedures gain importance in patients whose weight control can not be achieved. In recent years, sleeve gastrectomy (SG) has become very popular. Nevertheless, its effects on gastrointestinal system physiology and bone metabolism are still not known properly.
METHODS: Fifty-two patients who underwent SG between 2018 and 2019 were included in our observational study. Calcium, albumin, albumin-adjusted calcium (AAC), phosphorus (P), 25-hydroxyvitamin D [25(OH)D], alkaline phosphatase (ALP), parathyroid hormone (PTH), creatinine, glomerular filtration rate (GFR) and body mass index (BMI) of the patients were recorded both in the pre-operative period and three months postoperatively. Patients were grouped as patients with low calcium (10.2mg/dL) according to pre-operative and post-operative calcium levels.
RESULTS: The mean age of the patients was 38.96±8.93 years. 1 (8.33%) out of 12 patients with high serum calcium levels in the pre-operative period had low serum calcium levels in the post-operative period, eight patients (66.67%) had normal reference values, three patients (25%) had high serum calcium levels, the difference was significant. Based on ACC, eight patients (15.38%) had high calcium levels postoperatively.
DISCUSSION AND CONCLUSION: Hypocalcemia, normocalcemia, and hypercalcemia may be observed during the follow-up after bariatric surgery. Although PTH and 25(OH)D play the most important roles in calcium metabolism, the interaction of bone- gut hormones is still unclear and complicated.