Risk and Characteristics of Constipation After Metabolic and Bariatric Surgery: A Systematic Review and Meta-Analysis.

backgroundConstipation is a common yet often underrecognized gastrointestinal complication following metabolic and bariatric surgery (MBS). It not only affects patients' quality of life but may also lead to abdominal pain, bowel obstruction, and nutrient malabsorption. However, current findings regarding its incidence, risk factors, and variations across surgical procedures remain inconsistent.

objectiveTo comprehensively assess the risk of postoperative constipation, its procedure-specific differences, and related clinical characteristics after MBS, providing evidence-based insights for postoperative management and intervention.

methodsThis systematic review and meta-analysis followed the PRISMA guidelines and was prospectively registered in PROSPERO (Registration No. CRD 420251162054 ). A comprehensive search was conducted in PubMed, Embase, Web of Science, MEDLINE, and the Cochrane Library up to October 2025. Studies reporting constipation outcomes after MBS were included. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using a random-effects model, and subgroup analyses were performed based on surgical type.

resultsEight studies comprising 4,838 participants were included. The pooled analysis demonstrated no significant association between MBS and constipation risk (OR = 1.04, 95% CI: 0.62-1.73, p = 0.83), with substantial heterogeneity (I² = 82.9%). Subgroup analyses revealed procedure-dependent differences: biliopancreatic diversion (BPD) (OR = 0.19, 95% CI: 0.07-0.52) and Roux-en-Y gastric bypass (RYGB) (OR = 0.12, 95% CI: 0.04-0.38) were associated with a reduced risk, whereas adjustable gastric banding (AGB) significantly increased constipation risk (OR = 2.40, 95% CI: 1.08-5.33).Results for laparoscopic sleeve gastrectomy (LSG) were heterogeneous, with pooled data showing no significant association (OR = 1.31, 95% CI: 0.62-2.77). Sensitivity analyses and publication bias assessments confirmed the robustness of the findings.

conclusionsThe risk of constipation following MBS is strongly procedure-dependent. Malabsorptive or mixed procedures (e.g., BPD, RYGB) may lower constipation risk, whereas restrictive procedures (e.g., AGB) appear to increase it. LSG shows no consistent association. Individualized postoperative management-including adequate dietary fiber and fluid intake, maintenance of regular bowel habits, and early preventive interventions-may improve postoperative quality of life. Further large-scale, multicenter, prospective studies are needed to elucidate the underlying mechanisms and refine postoperative care strategies.