Bone mineral density after bariatric surgery. A systematic review

Bone regulation system may be affected after bariatric surgeries, but procedures impact differently to bone mineral density (BMD) and measures restraining bone loss are frequently neglected until clinical consequences become manifest. This is a systematic review aimed to elucidate whether BMD loss is comparable after different bariatric surgeries.

A search of morbid obese adults, undergone to bariatric surgery, with BMD measured by dual-energy X-ray absorptiometry at baseline and after surgery studies was performed in several databases. Studies were assessed using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and COCHRANE Risk of Bias tool. The random model was selected for meta-analysis; heterogeneity was analyzed with T(2), inconsistency (I(2) > 50%) and Chi(2) (p < 0.10). Level of evidence and strength of recommendations were summarized using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE System).

Twelve studies met the selection criteria. After one year, reduction in total BMD in patients with mixed surgical procedures was significant: -0.03 g/cm(2) (CI 95% 0.00 to -0.06, p < 0.05). BMD was reduced by -0.12 g/cm(2) (CI 95% -0.10 to -0.15, p < 0.001) in the hip, -0.07 g/cm(2) (CI 95% -0.03 to -0.11, p < 0.001) in the column, and -0.03 g/cm(2) (IC 95% -0.02 to -0.04, p < 0.001) in the forearm, but not in restrictive surgeries. Studies included showed high heterogeneity and low quality of evidence.

Patients undergone to mixed bariatric surgery had significant higher BMD deterioration as demonstrated in this review, suggesting that more attention for preventing fractures is required.