Secondary Hyperparathyroidism and Hypovitaminosis D One Year after Post-Bariatric Surgery

Presentation Number: SUN 353
Date of Presentation: April 2nd, 2017

Luciana Vercoza Viana*1, Luiza Ferreira Sperb2, Ana Carolina Rocha3 and Mirela J Azevedo4
1HCPA - Hospital de Clinicas de Porto Alegre, PORTO ALEGRE, 2Hospital de Clinicas de Porto Alegre, PORTO ALEGRE, Brazil, 3Hospital de Clinicas de Porto Alegre, 4Hospital de Clinicas de Porto Alegre, Brazil

Abstract

Introduction: Obese patients submitted to bariatric procedures have a high risk of secondary hyperparathyroidism (up to 53%) and hypovitaminosis D (33 to 96.7%) (1,2). Identification of aspects related to such variability is important to prevent morbid bone conditions (osteopenia, osteomalacia, and osteoporosis). The aim of this study was to evaluate factors associated with to vitamin D deficiency and secondary hyperparathyroidism (SHPT) in South Brazilian patients after one year of bariatric surgery (Y-en-Roux Bypass procedure).

Methods: In this retrospective cohort study (2010-2014) vitamin D deficiency was defined as serum 25(OH)D<20 ng/ml and SHPT as PTH>68 pg/ml, in patients with normal serum creatinine and calcium. Bone mineral density (BMD) was estimated by DXA - Lunar (g/cm2).

Results: From a total of 85 patients, 74 were included and had 38.8±14 months of follow-up after surgery with a mean weight loss of 75.5±26.3%. Patients’ characteristics were: age 46.3±11.4 years old, non-white ethnicity 15%, and female sex 86.5%. Pre-surgery and current BMI was 49.2±7.7 kg/m2 and 31.8±4.8 kg/m2, respectively. At the end of follow-up, diabetes mellitus was present in 5.4%, hypertension in 40.5%, dyslipidemia in 14.9%, and psychiatry disease in 35.1% of the participants. At baseline, 89% of patients used multivitamins and 37.8% calcium tablets; 92% consumed dairy products. At end-of-study, 59.5% of patients were taking vitamin D supplements [21.000UI weekly (P25-75 14000-28000)] and of them, 23% had received an initial high weekly dose of vitamin D. Mean 25(OH)D at baseline was 20.6±8.1 ng/ml. There was an increment of 25(OH)D deficiency between the first and last evaluation [11.5% to 48.1% (P=0.006)] and SHPT was identified in 56.8% at the beginning of the study [PTH = 77.5 pg/dl (P25-75 52.4-110.4; n=60)]. Patients with baseline SHPT used higher dose of vitamin D as compared to patients without SHPT: 14,167±7,039 vs. 28,148±20,450 UI/day (P=0.003). Values of 25(OH)D and weight loss were inversely correlated (r=-0.264; n=65) as well as 25(OH)D and PTH (r=-0.382; n=52) (P<0.05). An inverse correlation (P<0.05) was observed between BMD and PTH in lumbar spine (r=-0,432; n=29), total hip (r=-0.59; n=25), and femoral neck (r=-0.561, n=28), but not with vitamin D.

Conclusion: Development of vitamin D deficiency and SHPT were frequent after a long-term follow-up in patients who undergo bariatric surgery. BMD was inversely correlated to PTH, and a weak correlation occurred between 25(OH)D and PTH.

 

Nothing to Disclose: LVV, LFS, ACR, MJA