Preoperative comorbidities linked to reduced weight loss after metabolic and bariatric surgery in adults

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Obesity reviews : an official journal of the International Association for the Study of Obesity Published June 6, 2026 Medically reviewed June 6, 2026 Study authors: Atlantis Evan, Mariadasan Gabriel, Brooks Cristy, Piya Milan, Fahey Paul PubMed ↗ DOI ↗ By Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

Key Takeaway

Mental illness, diabetes, and sleep apnea are linked to slightly lower weight loss after surgery, while hypertension and dyslipidemia show no significant difference.

This rapid review analyzed data from twenty-three studies involving adult patients who underwent metabolic and bariatric surgery. The primary focus was on how preoperative comorbidities influenced weight loss outcomes over a follow-up period of at least six months. The analysis compared patients with existing health conditions against those without such conditions prior to the procedure.

Results indicated a negative association between mental illness, type 2 diabetes, and sleep apnea with weight loss success. Specifically, patients with these conditions experienced slightly lower weight loss compared to those without these specific comorbidities. Statistical measures confirmed these associations were significant, though the magnitude of the effect varied by condition.

In contrast, conditions such as hypertension, dyslipidemia, and metabolic syndrome did not demonstrate a statistically significant difference in weight loss outcomes. This suggests that while certain mental and metabolic disorders may hinder surgical success, other common cardiovascular risks do not appear to impact weight reduction in the same manner. Safety data and adverse events were not reported in the source materials.

Study Details

Study typeMeta analysis

EvidenceLevel 1

PublishedJun 2026

PMID41469194

View Original Abstract ↓

AIM: This rapid review aims to summarize the evidence of weight loss following Metabolic and Bariatric Surgery (MBS) associated with preoperative comorbidities. METHODS: Electronic databases Medline and EMBASE were searched for relevant articles up to and including September 2023. Studies that reported associations between the presence of comorbidities and weight loss outcomes in adult patients (age ≥ 18 years) after MBS (with ≥ 6 months of follow-up). Standardized mean differences (SMDs) with 95% confidence intervals (95% CIs) were calculated and pooled using random effects meta-analysis. Heterogeneity was quantified using the I statistic and tested for statistical significance using the Q-statistic. RESULTS: Twenty-three studies published between 2001 and 2023 were reviewed. Mental illness (SMD = -0.33, 95% CI: -0.53, -0.13; I = 64.72%, Q statistic p = 0.01), type 2 diabetes mellitus (SMD = -0.20, 95% CI: -0.36, -0.03; I = 56.88%, Q statistic p = 0.04), and sleep apnea (SMD = -0.28, 95% CI: -0.45, -0.12; I = 27.39%, Q statistic p = 0.24) achieved slightly lower weight loss outcomes compared to those without these comorbidities. There was no significant difference in weight loss after bariatric surgery between individuals with and without preoperative hypertension (SMD = -0.10, 95% CI: -0.22, 0.03), dyslipidemia (SMD = -0.05, 95% CI: -0.20, 0.10), and metabolic syndrome (SMD = -0.19, 95% CI: -0.58, 0.19). While other comorbidities were also linked to reduced weight loss, the statistical significance of these findings was more variable. CONCLUSIONS: Our evidence synthesis reveals an association between the presence of several preoperative comorbidities and less favorable weight loss outcomes following MBS.