Compared with standard obesity management, metabolic-bariatric surgery is associated with a greater reduction in risk for mortality in adults with obesity, with the benefits more significantly observed in patients with preexisting diabetes, according to research findings published in the Lancet.
A team of international researchers performed a meta-analysis of patient-level survival data from randomized controlled trials, matched cohort studies, and prospective controlled trials. Studies assessed all-cause mortality following metabolic-bariatric surgery compared with nonsurgical obesity management. Studies that exclusively enrolled patients with specific comorbidities other than type 2 diabetes (such as end-stage kidney failure and type 1 diabetes), adolescents, or were noncomparative studies and case reports were excluded from the analysis.
The meta-analysis included 17 trials including of a total of 174,772patients with obesity. A total of 7712 deaths occurred during a median follow-up of 69.4 months (1,156,376 patient-years).
In the pooled group of patients who underwent metabolic-bariatric surgery (n=65,785), 1813 deaths occurred during 496,771 patient-years. In contrast, 5899 deaths occurred during 659,605 patient-years in the group that did not receive bariatric surgery. (n=108,987).
Metabolic-bariatric surgery was associated with a reduction in the hazard rate of death by 49.2% compared with nonsurgical usual care (95% CI, 46.3%-51.9%; P <.0001). Additionally, patients who underwent metabolic-bariatric surgery had a median life expectancy that was 6.1 years longer than that of patients who underwent standard care only (95% CI, 5.2-6.9 years).
A subgroup analysis revealed that metabolic-bariatric surgery was also associated with lower all-cause mortality rates than standard care in patients with diabetes at baseline (hazard ratio [HR], 0.409; 95% CI, 0.370-0.453; P <.0001) and without diabetes at baseline (HR, 0.704; 95% CI, 0.588-0.843; P <.0001).
Among patients with diabetes at baseline, surgery was associated with a median life expectancy that was 9.3 years (95% CI, 7.1-11.8 years) longer than with standard care. In contrast, surgery vs standard care was associated with a median life expectancy gain that was 5.1 years longer in patients without diabetes.
Overall, the effect of bariatric surgery was more significant in patients with diabetes at baseline (between-subgroup I2=95.7%; P <.0001). At the 10- and 20-year follow-up, the numbers needed to treat to prevent 1 additional death were 8.4 (95% CI, 7.8-9.1) and 5.3 (95% CI, 4.9-5.8), respectively, for patients with diabetes. For those without diabetes, the numbers needed to treat to prevent 1 additional death were 29.8 (95% CI, 21.2-56.8) at 10 years and 19.0 (95% CI, 13.4-36.3) at 20 years.
Researchers acknowledged several limitations to the study, such as the availability of newer classes of diabetes and obesity medications in the nonsurgical control groups at the time they were studied. Additionally, the researchers noted that many of these newer classes of drugs may also reduce the risk for cardiovascular death and hospitalization.
However, in light of the overall findings, the researchers noted “clinicians and policymakers should not hesitate to consider metabolic-bariatric surgery in the management of patients with obesity and type 2 diabetes.”
Disclosure: Multiple authors declared affiliations with the pharmaceutical industry. Please refer to the original article for a full list of disclosures.
Syn NL, Cummings DE, Wang LZ, et al. Association of metabolic-bariatric surgery with long-term survival in adults with and without diabetes: a one-stage meta-analysis of matched cohort and prospective controlled studies with 174 772 participants. Lancet. 2021;397(10287):1830-1841. doi: 10.1016/S0140-6736(21)00591-2