All-cause mortality substantially decreased following metabolic-bariatric surgery among patients with obesity, according to findings from a meta-analysis published in The Lancet.

Publication databases were searched through February 2021 for randomized, prospective controlled studies of metabolic-bariatric surgery compared with nonsurgical obesity management.

This study assessed 17 studies comprising 174,772 patients with a median follow-up of 69.4 (interquartile range [IQR], 42.2-84.9) months.


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The cumulative mortality at 30 years was 29.5% among the surgical group and 46.0% among the nonsurgical group, indicating a reduced risk for all-cause mortality following metabolic-bariatric surgery (hazard ratio [HR], 0.529; 95% CI, 0.462-0.605).

The investigators projected that metabolic-bariatric surgery corresponded with an increased median life expectancy of 6.1 (95% CI, 5.2-6.9) years.

Stratified by surgery type, reduced all-cause mortality was associated with Roux-en-Y gastric bypass (HR, 0.430; 95% CI, 0.387-0.478; P <.0001), sleeve gastrectomy (HR, 0.475; 95% CI, 0.354-0.639; P <.0001), and adjustable gastric banding (HR, 0.500; 95% CI, 0.401-0.624; P <.0001). This analysis had little evidence of between-group study heterogeneity (I2, 3.4%; P =.36).

Among patients with type 2 diabetes, 456 deaths occurred among the 16,190 patients who underwent surgery compared with 2939 of the 38,853 patients who did not. These mortality rates corresponded with an HR of 0.409 (95% CI, 0.370-0.453; P <.0001) for all-cause mortality and an increased 9.3 (95% CI, 7.1-11.8) years of life.

For patients without type 2 diabetes, metabolic-bariatric surgery decreased all-cause mortality (HR, 0.704; 95% CI, 0.588-0.843; P <.0001) and increased life expectancy by 5.1 (95% CI, 2.0-9.3) years.

Significant between-group study heterogeneity was detected (I2, 95.7%; P <.0001).

The current rate of metabolic-bariatric surgery is approximately 1% among the 184 million people worldwide who are severely obese. For the scenario in which surgery rates were increased to 3.5% among patients with diabetes and 2.0% among those without diabetes, an additional 19,402,800 life-years would be gained.

This study had little power to detect differences between subgroups.

This study found that metabolic-bariatric surgery was associated with significant reductions in all-cause mortality and increases in life expectancy among patients who were severely obese. This effect was more pronounced among patients with diabetes.

Disclosure: Some authors declared affiliations with biotech, pharmaceutical, and/or device manufacturers. Please refer to the original article for a full list of authors’ disclosures.

Reference

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