Effects of diabetes and smoking on lumbar spinal surgery outcomes.

Smoking and diabetes have long been considered risk factors for poor surgical outcome. However, the precise role of smoking and diabetes in the development of poor outcome in lumbar spinal surgery remains ambiguous. This study was undertaken to determine the effects of diabetes and smoking specifically on lumbar spinal surgery outcomes. A retrospective cohort study studied 902 patients who underwent lumbar spinal surgery at the Royal Melbourne Hospital, Australia, between 2001 and 2005, inclusively. Four groups were formed: control; diabetic; positive smoking history; and diabetic and positive smoking history. Multivariate analysis was used to analyse the likelihood of developing complications with a history of diabetes and/or smoking. Our findings indicate that diabetes was significantly associated with an increased risk of developing complications. Patients in the diabetic groups were also significantly older and had a longer length of stay than the other patients (p<0.05 for all significant findings). We conclude that diabetes does increase the risk of poor outcome following lumbar spinal surgery. However, we found no association between a positive smoking history and an increased rate of poor outcome.