Analysis of risk factors for postoperative bleeding in anal surgery: A retrospective cohort study

Abstract

Postoperative hemorrhage is the most common and potentially serious complication following anal surgery, increasing hospitalization time, healthcare costs, and patient morbidity. This study aimed to identify independent risk factors associated with postoperative bleeding in patients undergoing anorectal surgery. We conducted a retrospective cohort study of 150 patients who underwent anorectal surgery at our institution from January 1, 2020, to December 31, 2024. Clinical variables - including demographics, comorbidities, medication history, laboratory tests, surgical features, and perioperative management - were collected and analyzed. Postoperative bleeding was defined as persistent hemorrhage requiring intervention, hemoglobin decrease ≥ 20 g/L, transfusion, or reoperation within 30 days. Variables with P < .05 in univariate analysis were included in a forward stepwise logistic regression model. Among 150 patients who underwent anorectal surgery, postoperative bleeding occurred in 20 cases, yielding an incidence of 13.3%. Univariate analysis revealed that bleeding was significantly associated with use of anticoagulants (P = .002), more than 3 previous anorectal procedures (P = .014), thrombocytopenia (P = .006), elevated activated partial thromboplastin time (P = .018), trauma area > 10 cm2 (P = .004), and first postoperative bowel movement within 24 hours (P = .001). These variables were entered into a forward stepwise multivariate logistic regression model. The final model identified 5 independent predictors of bleeding: warfarin therapy (OR = 4.36; 95% CI = 1.85-7.82; P = .001), more than 3 prior anorectal surgeries (OR = 2.59; 95% CI = 1.72-4.28; P = .012), preoperative platelet count < 100 × 109/L (OR = 3.11; 95% CI = 1.50-5.62; P = .005), surgical trauma area > 10 cm2 (OR = 3.80; 95% CI = 1.47-6.45; P = .003), and first defecation within 24 hours after surgery (OR = 2.31; 95% CI = 1.10-4.16; P = .002). The Hosmer-Lemeshow test indicated good model fit (P = .472). Preoperative correction of coagulopathy, minimization of surgical trauma, and delayed bowel movements beyond 24 hours postoperatively may reduce the risk of postoperative hemorrhage. These findings offer guidance for individualized risk assessment and targeted preventive strategies in anorectal surgery.

Keywords: anal surgery; independent risk factors; logistic regression; platelets; postoperative bleeding.