eP528 - Through the Smoke: A Deeper Look at Preoperative Smoking on Colorectal Surgery Outcomes

Purpose/Background: Smoking is an established risk factor for increased postoperative complications. Despite this, there is limited data on characteristics of smokers that intensify risk. This study aims to investigate the effect of preoperative smoking duration and intensity, periods of cessation, and concurrent smokeless product use on colorectal surgery outcomes.Methods/Interventions: A retrospective cohort study was conducted on current and former smokers who underwent colorectal surgery from 2012 to 2022 at the University of Virginia. Patients with limited smoking documentation were omitted. Follow-up was 30-days postoperatively. The primary endpoint was major adverse events (MAE), defined as incidence of major bleeding, venous-thromboembolism, acute kidney injury, myocardial infarction, acute respiratory distress syndrome, stroke, infection, mortality, or readmission.Results/Outcomes: 239 current or former smokers underwent colorectal surgery, with the most common procedure being colon resection. The average age at procedure was 63.9±0.85 years, average smoking duration was 27±1.02 years, average packs per day (PPD) was 0.94±0.04 packs, and average pack-years was 26±1.71. 11% of patients were concurrent smokeless product users (chew, dip, and/or vape). Half of patients (50%) quit smoking prior to surgery. Median duration of cessation, defined as time between quit date and operation in former smokers, was 14.8 years.In the 30 days following surgery, 28% of patients had one or more MAE. The most frequent MAE was major bleeding (51.9%). Independent predictors of increased MAE were pack-years (P = 0.004), vape use (P = 0.017), and younger age at procedure (P = 0.025). Years of tobacco use (P = 0.003) was an independent predictor of MAE, whereas PPD (P = 0.244) was not. After adjusting for pack years, patients with MAE had significantly longer smoking duration (30.2 vs 25.1 years, P = 0.02) but not higher PPD (1.03 vs 0.90, P = 0.18) compared to those without MAE after. Former smoker status (P = 0.049) had significantly fewer MAE than current smokers. Of patients that quit smoking, those with longer durations of cessation (> 20 years), had fewer MAE than those who quit more recently, with a trend towards significance (P = 0.071).Conclusion/

Discussion: In this study, we found that the longer duration of smoking had greatest effect on MAE after colorectal surgery, more so than the greater intensity of tobacco use (PPD). Patients that quit smoking had significantly fewer MAE, and those with higher durations of cessation had a trend towards better outcomes. Concurrent use of tobacco with vaping was significantly associated with MAE. Colorectal surgery providers should encourage pre-operative smoking cessation and counsel patients with significant duration of smoking regarding their increased risk of MAE.Table 1. Predictors of Major Adverse Events (MAE)Independent predictors and smoking status predictors of MAE.
CI = Confidence interval, P-value ** = < 0.01, * = < 0.05