Bone loss following bariatric surgery: Comparison of different modalities — ASN Events

Bone loss following bariatric surgery: Comparison of different modalities (#24)

Malgorzata M Brzozowska 1 2 , Dana Bliuc 2 , Angel Hong 3 , John Jorgensen 4 , Michael Talbot 4 , Nguyen Dinh Nguyen 2 , Weiwen Chen 1 5 , Nicholas Pocock 6 , John A Eisman 1 2 7 8 , Christopher P White 3 , Paul A Baldock 8 9 , Jacqueline R Center 1 2 8
  1. Endocrinology, St Vincent's Hospital, Darlinghurst, NSW, Australia
  2. Musculoskeletal Diseases Division, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
  3. Clinical&Laboratory Endocrinology, Prince of Wales Hospital, Randwick, NSW, Australia
  4. St George Private Hospital, Kogarah, NSW, Australia
  5. Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
  6. Nuclear Medicine, St Vincent's Hospital, Darlinghurst, NSW, Australia
  7. University of Notre Dame, Darlinghurst, NSW, Australia
  8. Faculty of Medicine, University of New South Wales, Kensington, NSW, Australia
  9. Neurological Disease Division, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia

Although bariatric surgery is the most effective weight loss therapy, its skeletal consequences are unclear. We examined the interrelationship between weight loss, gut hormones, adiponectin and bone loss in people undergoing Medical Managed Dieting (MMD), Gastric Banding (GB) and Gastric Sleeve (GS).

There were 15 MMD, 8 GB and 20 GS subjects with mean (±SD) age 53 (12) yrs and BMI 39 (6). There were no differences in baseline characteristics between groups.

At 12 mths mean (±SD) % weight change was MMD -4.5 (5), GB -12 (6), and GS -26 (8), P<0.0001. Bone loss [total hip (TH), %] was non-significant in MDD -0.86 (1.6) and GB -1.6 (1.5). However, for GS, although maximal weight loss occurred in the first 6 months, bone loss continued: 3.5 (2) % at 6 months, 6.1(3) % at 12 months, P<0.0001. The mean postprandial PYY % (+90 min) response differed between groups: MMD 58 (102), GB 70 (74), GS 150 (106), P<0.0008. GLP-1 was not significantly altered. Change in adiponectin (%) varied between groups: MMD 4 (22), GB 21 (19), GS 75 (62), P=0.0022. Bone turnover markers increased only in GS with osteocalcin by 110 (89) % and uNTX by 89 (83) %, P<0.001. Calcium intake, vitamin D and PTH were normal throughout.

For all study patients 50 % of their BMD loss was explained by weight loss (P<0.001) with another 16% by increase in postprandial PYY, P=0.010 and 13% by adiponectin, P=0.02.

The 12 GS patients with 24 months data had ongoing BMD loss with a decline in TH BMD by 9 (3) %, P<0.001 despite no further weight loss.

GS was the most efficient weight loss modality. It was complicated by ongoing bone loss that was not accounted for by weight loss alone but was associated with postprandial PYY and adiponectin changes. These findings have significant clinical implications for people undergoing bariatric surgery.

DISCLOSURES: JAE: Scientific Board Member of Merck & Co, Novartis, Sanofi, Servier, Eli Lilly & Company, Amgen. JRC: Speaker, Amgen, Merck & Co, Novartis Pharmaceuticals, Sanofi. Nothing to Disclose: MMB, DB, AH, JJ, MT, NDN, WC, NAP, CPW, PAB

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