Body mass index and smoking status as predictors of progression to surgery, complications and postoperative pain in non-traumatic back pain patients KR

Abstract

Objective: While the adverse effects of both smoking and obesity on health are well established, the relationship of smoking and obesity to poor outcomes in specific surgical procedures are less well studied. The aim of this study was to quantify the risks of smoking and obesity in patients who are presenting to spine surgeons for evaluation of non-traumatic back pain. Methods: Retrospective review of prospectively collected data of patients with non-traumatic back pain who presented to a spine surgeon in an academic tertiary referral setting. There were three binary dependent variables: the patient had surgery (yes/no), the patient had postoperative pain (yes/no) and the patient had complications (yes/no). All other variables were considered independent. First, we examined 367 patients (Group 1) presenting for non-traumatic back pain. Next, we examined the subset of 185 patients (Group 2) who proceeded to surgery. Results: The final logistic model predicting progression to surgery included the variable smoking status. The odds ratio for proceeding to surgery in Group 1 of a smoker versus non-smoker was OR = 2.47 (p < 0.01, 95% confidence interval = 1.60 to 3.81). For the patients who had undergone surgery (Group 2), separate logistic models were created to predict complications and pain. The odds ratio for complications: with each increase in body mass index (BMI) of 5 kg/m2 OR = 1.41, (p < 0.01, 95% confidence interval = 1.11 to 1.80); with positive smoking status OR = 4.85, (p < 0.01, 95% confidence interval = 2.32 to 10.15). The odds ratio for postoperative pain with each increase in BMI of 5 kg/m2 was OR = 1.95 (p < 0.01, 95% confidence interval = 1.47 to 2.59). Conclusion: Smokers who presented to our clinic with non-traumatic back pain are more likely to receive a surgical intervention than non-smokers. In patients who undergo surgery, both increased BMI and positive smoking status are associated with a greater likelihood of complications. Body mass index alone, but not smoking status, is associated with a greater likelihood of postoperative pain.