INCREASED BONE TURNOVER IN TYPE 2 DIABETES PATIENTS RANDOMIZED TO BARIATRIC SURGERY VERSUS MEDICAL THERAPY AT 5 YEARS.

OBJECTIVE: The aim of our study was to determine the 5-year outcomes of bariatric surgery versus intensive medical therapy on bone turnover in patients with type 2 diabetes mellitus (T2DM) from the STAMPEDE trial.

METHODS: This was an ancillary investigation of a 5-year randomized control trial at a single tertiary care center involving 95 patients aged 48.5 ± 8 years with obesity (body mass index [BMI], 36.5 ± 3.6 kg/m2 ) and uncontrolled T2DM (glycated hemoglobin 9.3 ± 1.6% [78 mmol/mol]). Patients were randomized to intensive medical therapy (IMT; n = 25), Roux-en-Y gastric bypass (RYGB; n = 37), or sleeve gastrectomy (SG; n = 33) for diabetes treatment. Bone formation marker osteocalcin (OC), bone resorption marker serum C-telopeptide of type 1 collagen (CTX), and intact parathyroid hormone (PTH) were assessed at baseline and 5 years postintervention. Analysis with key clinical parameters and outcomes (i.e., age, menopausal status, gender, weight loss) was performed.

RESULTS: Percent change in CTX at 5 years increased in both surgical groups, by 137 ± 108% in RYGB ( P<.001) and 61.1 ± 90% in SG ( P<.001) compared to 29.8 ± 93% in IMT ( P = .12). OC also increased from baseline in the surgical cohorts, by 138 ± 19% in RYGB ( P<.001) and 71 ± 69% in SG ( P<.001) compared to 43.8 ± 121.1% in IMT ( P = .83). Increases in both CTX and OC correlated linearly with increases in PTH levels in RYGB patients ( P<.001). Increase in CTX correlated with decreased BMI in SG patients ( P = .039).

CONCLUSION: In patients with T2DM, bone turnover remains chronically elevated at 5 years following RYGB, and to a lesser extent in SG patients.

ABBREVIATIONS: BMI = body mass index; BTM = bone turnover marker; CTX = C-telopeptide of type 1 collagen; HbA1c = glycated hemoglobin; IMT = intensive medical therapy; OC = osteocalcin; PPI = proton-pump inhibitor; PTH = parathyroid hormone; RYGB = Roux-en-Y gastric bypass; SG = sleeve gastrectomy; T2DM = type 2 diabetes mellitus; TZD = thiazolidinedione.