Metabolic and bariatric surgery for patients with obesity type 1 diabetes mellitus: A comprehensive updated systematic review and meta-analysis.
Sebastian Mitchell, Ketaki Patwardhan, James Lucocq et al.
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In 30 seconds
This PRISMA-compliant systematic review and meta-analysis assessed metabolic and bariatric surgery (MBS) outcomes in adults with obesity and type 1 diabetes. Across 22 studies involving 1324 adults, surgery was associated with substantial reductions in body weight and BMI, while HbA1c fell only modestly. Insulin requirements declined by 43%-48% (0.20 U/kg; 95% CI 0.13 to 0.26). Reported postoperative events included diabetic ketoacidosis and severe hypoglycaemia. The authors rated the evidence quality as low and noted that observational data and inconsistent safety reporting leave metabolic risks uncertain.
Key findings
- Body weight decreased by a mean 29.55 kg (95% CI 25.72 to 33.39; I 2 = 20%).
- BMI decreased by a mean 11.35 kg/m 2 (95% CI 10.36 to 12.34; I 2 = 32%).
- HbA1c decreased by 4 mmol/mol (95% CI 2.05 to 6.78; I 2 = 19%), a modest glycaemic improvement.
- Insulin requirements declined by 43%-48% (0.20 U/kg; 95% CI 0.13 to 0.26); evidence quality was low.
Why it matters
For adults with obesity and type 1 diabetes, MBS may produce substantial weight loss and reduce insulin requirements, but the pooled HbA1c change was small. These outcomes should be considered alongside reported postoperative ketoacidosis and severe hypoglycaemia, and the low certainty of the evidence. The review highlights that weight and insulin outcomes do not establish improved overall metabolic safety.
What to keep in mind
The evidence was low quality and based on observational studies; safety reporting was inconsistent, leaving true metabolic risk uncertain.