Hospital length of stay and readmission after elective surgery: a comparison of current and former smokers with non-smokers

Background: The purpose of this study was to investigate differences between non-smokers, ex-smokers and current smokers in hospital length of stay (LOS), readmission (seven and 28 days) and cost of readmission for patients admitted for elective surgery. Methods: A retrospective cohort study of administrative inpatient data from 24, 818 patients admitted to seven metropolitan hospitals in Western Australia between 1 July 2016 and 30 June 2019 for multiday elective surgery was conducted. Data included smoking status, LOS, procedure type, age, sex and Indigenous status. LOS for smoking status was compared using multivariable negative binomial regression. Odds of readmission were compared for non-smokers and both ex-smokers and current smokers using separate multivariable logistic regression models. Results: Mean LOS for non-smokers (4.7 days, SD=5.7) was significantly lower than both ex-smokers (6.2 days SD 7.9) and current smokers (6.1 days, SD=8.2). Compared to non-smokers, current smokers and ex-smokers had significantly higher odds of readmission within seven (OR=1.29; 95% CI: 1.13, 1.47, and OR=1.37; 95% CI: 1.19, 1.59, respectively) and 28 days (OR=1.35; 95% CI: 1.23, 1.49, and OR=1.53; 95% CI: 1.39, 1.69, respectively) of discharge. The cost of readmission for seven and 28-day readmission was significantly higher for current smokers compared to non-smokers (RR=1.52; 95% CI: 1.1.6, 2.0; RR=1.39; 95% CI: 1.18, 1.65, respectively). Conclusion: Among patients admitted for elective surgery, hospital LOS, readmission risk and readmission costs were all higher for smokers compared with non-smokers. The findings indicate that provision of smoking cessation treatment for adults undergoing elective surgery is likely to produce multiple benefits.