Abstract
Introduction: Rectal fistulas (RF) and type 2 diabetes mellitus (T2DM) frequently coexist. This study examines clinical, microbiological, immunological, and physiological characteristics of RF in patients with T2DM to determine whether a mutual exacerbation phenomenon exists.
Methods: This retrospective cohort included 114 adults who underwent rectal fistula surgery. Patients were grouped into those with T2DM (n=54) and controls without diabetes (n=60). Multivariate logistic regression was used to identify predictors of postoperative complications. Outcomes are reported as mean±SD, percentages, effect sizes, and 95% confidence intervals.
Results: Purulent cavities (33.3% vs. 15.0%, P=0.02), and inflammatory cytokines (IL-6: 32.4±8.7 vs. 18.9±6.2 pg/mL, P=0.002; IL-10: 25.1±7.3 vs. 14.6±5.1 pg/mL, P=0.005) were significantly more common in T2DM patients. Lower IFN-γ levels were observed in T2DM (45.2±12.1 vs. 68.7±15.3 pg/mL, P=0.008). Enterobacteriaceae predominated in both groups but were more frequent in T2DM (55.6% vs. 46.7%, P=0.04). Sphincter dysfunction was more prevalent in T2DM (28.3% vs. 8.3%, P=0.004). Eight patients (13.3%) with previously controlled diabetes developed worsening glycemic control after RF formation. Multivariate analysis identified poor glycemic control (aOR 2.91, 95% CI: 1.19–6.23) and presence of purulent cavity (aOR 3.02, 95% CI: 1.28–6.11) as independent predictors of postoperative complications.
Conclusion: T2DM and rectal fistula exert a mutual exacerbating effect, worsening of inflammation, glycemic regulation, fistula complexity, and postoperative outcomes. Integrating rigorous glycemic optimization, early imaging for purulent collections, cytokine-based risk stratification, and targeted microbiological therapy may improve outcomes in RF patients with diabetes.