Impact of visceral obesity on infectious complications after resection for colorectal cancer: a retrospective cohort study

Objectives To explore the impact of visceral obesity (VO) measured by preoperative abdominal computed tomography (CT) on postoperative infectious complications for colorectal cancer (CRC) patients and establish a predictive model.

Methods Patients who underwent resection for colorectal cancer between January 2015 and January 2021 were enrolled in this study.

All patients were measured for body mass index (BMI) and visceral fat area (VFA) preoperatively.

Infectious complications were compared between the different groups according to BMI and VO categories.

Univariate and multivariate logistic regression were used to analyze whether VO was an independent risk factor for postoperative infectious complications.

According to the results of logistic regression, six machine learning approaches were used to establish predictive models and perform internal validation.

The best-performing model was interpreted by the SHAPley Additive exPlanations value.

Results Approximately 64.81% of 520 patients had VO.

VO was significantly connected with postoperative infectious complications ( P  < 0.001), coronary heart disease ( P  = 0.004), cerebral infarction ( P  = 0.001), hypertension ( P  < 0.001), diabetes ( P  < 0.001), and fatty liver ( P  < 0.001).

The rates of wound infection ( P  = 0.048), abdominal or pelvic infection ( P  = 0.006), and pneumonia ( P  = 0.008) increased obviously in patients with VO.

Compared to the low BMI group, a high BMI was found to be significantly associated with hypertension ( P =0.007), fatty liver ( P ＜0.001), and a higher rate of postoperative infection ( P =0.003).

The results of logistic regression revealed that VO (OR = 2.01, 95% CI 1.17 ~ 3.48, P  = 0.012), operation time ≥ 4 h (OR = 2.52, 95% CI 1.60 ~ 3.97, P  < 0.001), smoking (OR = 2.04, 95% CI 1.16 ~ 3.59, P  = 0.014), ostomy (OR = 1.65, 95% CI 1.04 ~ 2.61, P  = 0.033), and chronic obstructive pulmonary disease (COPD) (OR = 2.23, 95% CI 1.09 ~ 4.57, P  = 0.029) were independent risk factors.

The light gradient boosting machine (LGBM) model displayed the largest area under the receiver operating characteristic curve (AUC) (0.74, 95% CI 0.68 ~ 0.81).

Conclusions In this study, VO was superior to BMI in evaluating the influence of obesity on metabolic comorbidities and postoperative infectious complications in colorectal cancer patients.