ObjectiveTo investigate the effect of preoperative smoking intervention on the incidence of postoperative complication in patients undergoing total hip replacement. MethodsPatients undergoing elective total hip replacement were randomly (block randomization) assigned to either smoking intervention group or control group 4 weeks before scheduled hip replacement. Smoking intervention group received counseling and nicotine replacement therapy and achieved smoking cessation or at least 50% smoking reduction while the control group received standard care with little or no information about the risk of smoking or smoking cessation counselling. Anesthesia was done in accordance with the practice of our hospital with either general anesthesia or combined spinal-epidural anesthesia (CSEA). An assessor who was masked to the intervention recorded the incidence of cardiopulmonary, renal, neurological, or surgical complications and duration of hospital admittance and treatment in intensive care unit (ICU) of two groups of patients. ResultsA total of 120 patients were finally included (60 cases were in each group, all male, ASAⅠ-Ⅲ, aged 65-82 years, weighting 42-75 kg). A total of 56 patients in the smoking intervention group and 57 in the control group were analyzed finally. The results showed that, the smoking intervention group was lower than the control group in the incidences of post-operative complications (12/56 vs. 39/57, P=0.000), postoperative wound-related complications (3/56 vs. 21/57, P=0.000), incision infection (1/56 vs. 13/57, P=0.001), and the requirement of secondary surgery (1/56 vs. 9/57, P=0.022) and wound debridement (1/56 vs. 8/57, P=0.040). The median length of stay in the smoking intervention group was significantly less than that of the control group (14 days vs. 26 days, P=0.000). ConclusionAn effective smoking intervention 4 weeks before surgery reduces incidence of postoperative complications.