Preoperative comorbidities associated with weight loss following metabolic and bariatric Surgery: a rapid review

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 I² 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; I² = 64.72%, Q statistic p = 0.01), type 2 diabetes mellitus (SMD = −0.20, 95% CI: −0.36, −0.03; I² = 56.88%, Q statistic p = 0.04), and sleep apnea (SMD = −0.28, 95% CI: −0.45, −0.12; I² = 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.