P46 Changes in bone mineral metabolism after bariatric surgery in patients with type 2 diabetes mellitus and obesity

Abstract

Introduction: Bariatric surgery (BS) is a highly effective treatment for patients with type 2 diabetes and obesity but it has negative effects on bone mineral metabolism.

Objectives: To evaluate bone mineral metabolism changes after BS in a diabetic and obese population.

Materials and methods: 56 patients were evaluated preoperative and postoperative (BS). Personal background, anthropometric measurements, body mass index (BMI), calcium, phosphorus, magnesium, creatinine, ionogram in plasma (mg/dl, g/dl, mEq/L) and 24hs urine (mg/24hs, mEq/ 24hs), albumin (gr/dl), 25 OH vitamin D (ng/ml) were analyzed. Statistical analysis: Student’s and Mann-Whitney-Wilcoxon tests were applied. Spearman correlation coefficient was calculated. Values expressed in average ± standard deviation. Significant p< 0,05.

Results: The sample consisted of 35 female and 21 male with a mean age of 52±9,6. One anastomosis gastric bypass (OAGB) was performed in 29 patients and laparoscopic Roux-en-Y gastric bypass (LRYGB) in 27. Pre and postoperative data was analyzed. Postoperative data with a time lapse between 3 to 79 months, average of 31.6. There was statistical significant reduction between pre BS and post BS levels for the following variables: calcemia 9,36±0,42 vs 9,12±0,47 (p 0,02); magnesemia 1,96±0,18 vs 1,92±0,18 (p 0,03); creatinine 0,81±0,23 vs 0,77±0,23 (p 0,003); natremia 139±2,62 vs 138±2,93 (p 0,02); and a statistical significant increased between pre BS and post BS levels for the following: phosphatemia 3,66±0,62 vs 4,02±0,57 (p 0,002); phosphaturia 48±28 vs 70±30 (p 0,002); creatininuria 1251±422 vs 1456±473 (p 0,03); vitamin D 23 ±8,8 vs 29±11 (p 0,01). We found negative significant correlation between time in months after surgery and urinary volume (r -0,35 p 0,05). Urinary calcium significantly differs (p=0,03) depending on the type of BS in favor of OAGB. Negative significant correlation was found between BMI and magnesemia r -0,39 (p 0,03).

Conclusions: The negative effects on bone mineral metabolism and BS are multifactorial, the decrease in calcemia, magnesemia, natremia and calciuria could be explained by the lower intestinal absorption after BS. Less urinary volume in post BS group can be attributed to less gastric volume. Knowing these consequences allows us to keep working in a better follow up treatment.