Background

Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) are the most common bariatric surgeries. While bariatric surgery is associated with the resolution of several obesity-related comorbidities, it can induce bone loss. Data regarding the impact of these two surgeries on bone mineral density (BMD) are sparse. This meta-analysis aims to compare BMD changes after RYGB vs. SG.

Methods

MEDLINE and EMBASE were searched through December 05, 2021, for eligible studies assessing BMD pre and post RYGB versus SG. The primary outcome was BMD changes: femoral neck BMD (FN-BMD), lumbar spine BMD (LS-BMD), total hip BMD (TH-BMD), and total body BMD (TB-BMD). The secondary outcomes were serum parathyroid hormone (PTH), calcium, and vitamin D levels. Data were pooled using the random-effects model and expressed as standardized mean difference (SMD) with 95% confidence intervals (CI).

Results

Five studies with 307 patients with obesity (157 patients underwent RYGB and 150 underwent SG) were included. Average follow-up period was 33.6 months (range 12-60). FN-BMD significantly decreased after RYGB compared to SG (SMD -0.46; 95% CI, -0.84, -0.08; P=0.02), but TH-BMD, LS-BMD, and TB-BMD were comparable between the two surgeries (Figure 1). There was no difference in calcium and PTH levels between the two surgeries, but RYGB was associated with lower vitamin D levels (SMD -0.63; 95% CI, -0.93, -0.32; P<0.001) (Figure 1).

Conclusions

Compared to SG, we found a decrease in FN-BMD in patients who underwent RYGB with comparable LS-BMD, TH-BMD, and total BMD. Large-scale studies are needed to validate our findings.