Diabetes and Patient Outcomes Following Lumbar Fusion

Methods: This study analyzed data from the Nationwide Inpatient Sample database for over 163,000 patients undergoing elective lumbar spine fusion between the years 1988 through 2003. Over 9,000 patients (5.5%) had been previously diagnosed with diabetes mellitus. Multiple linear and logistic regression models were used to ascertain whether these patients with diabetes mellitus were more likely than their non-diabetic counterparts to die while in the hospital, to have in-hospital postoperative complications, to stay longer in the hospital, to have a higher incidence of non-routine discharge, and to have a higher total cost associated with the procedure.

Results: Bivariate analysis demonstrated that diabetes was significantly associated with postoperative infection, need for transfusion, pneumonia, in-hospital mortality, and non-routine discharge (p <0 .02). Multivariate regression analysis, however, suggested no difference in mortality although infection, pneumonia, and non-routine discharge continued to be highly significant (p < 0.002). The odds ratios of postoperative infection transfusion were 1.64 (95% CI 1.20 - 2.23) 1.46 1.36-1.56) respectively. Although the length stay was not significantly different, inflation adjusted cost over $3000 more diabetic patients (mean $37,924 versus $40,958).

Conclusions: This large study of inpatients in the United States provides evidence that diabetic patients undergoing lumbar fusion are at increased risk for postoperative complications, in-hospital mortality, non-routine discharge, and increased total cost. The database is nationally representative and includes data spread over fifteen years. These results are important in patient selection and informed consent. Further research is ongoing to determine if normalization of hyperglycemia can impact the morbidity and mortality of these procedures in patients with diabetes.