Alterations of bone markers in obese patients with type 2 diabetes after bariatric surgery A meta-analysis and systemic review of randomized controlled trials and cohorts

Background: The aim of this study is to evaluate the alterations in bone mineral density and other surrogate markers for osteoporosis in obese patients with type 2 diabetes mellitus (T2DM) who received Roux-en-Y gastric bypass (RYGB) versus medical treatment as control. Methods: We searched 4 electronic databases and reference lists of relevant studies for eligible research published before December, 2019. After quality assessment, eligible studies were synthesized for relevant outcomes, including lumbar spine bone mineral density (L-spine BMD) change, total hip BMD change, osteocalcin level, C-terminal telopeptide level, and parathyroid hormone level. Results: Three randomized clinical trials and 2 observational studies concerning 307 total obese T2DM patients were included. Follow-up ranged from 12 to 60 months. Patients underwent RYGB surgery were associated with both higher L-spine BMD loss (mean difference: -2.90, 95% CI: -2.99 similar to-2.81, P < .00001) and total hip BMD loss (mean difference: -5.81, 95% CI: -9.22 similar to-2.40, P = .0008). As to biochemical markers of bone metabolism, we found significantly higher osteocalcin level in medical treatment (control) group compared with RYGB group (mean difference: 11.16, 95% CI: 8.57-13.75, P < .00001). However, higher C-terminal telopeptide level and parathyroid hormone level were noted in medical treatment group (control) compared with RYGB group (mean difference: 0.29, 95% CI: 0.11-0.48, P = .002; mean difference: 1.56, 95% CI: 0.84-2.27, P < .0001). Conclusions: RYGB surgery is associated with negative impact on bone metabolism and increase the risk of osteoporosis in obese patients with T2DM. We suggest that clinicians acknowledge the adverse effects of surgery and keep monitoring bone mineral components in post-RYGB populations. Further studies regarding the optimal amount of perioperative and postsurgical supplementation should be evaluated.