Diabetes Is Related to Worse Patient-Reported Outcomes at Two Years Following Spine Surgery

Background: Diabetes has been associated with poor outcomes following elective spine surgery. The purpose of our study was to determine if diabetes predicts worse patient-reported outcomes at two years postoperatively and to evaluate the effect of perioperative blood glucose levels and control on patient-reported outcomes in patients with diabetes. Methods: One thousand and five patients undergoing elective spine surgery were included in this prospective cohort study. The presence of diabetes and baseline and one and two-year patient-reported outcomes (Short Form-12 [SF-12], EuroQol-5D [EQ-5D], Oswestry Disability Index [ODI] or Neck Disability Index [NDI], and Numeric Rating Scale [NRS] pain scores) were recorded. The mean blood glucose measurements in patients with diabetes were collected during the postoperative period. Multivariable linear regression analyseswere performed to determine predictors of one and two-year outcomes aswell as the relationship between perioperative blood glucose and patient-reported outcomes in patients with diabetes. Results: Four hundred and thirty-four patients (43%) had diabetes. When compared with patients without diabetes at two years, patients with diabetes had lower SF-12 Physical Component Summary scores (34.4 points for the diabetic group compared with 38.6 points for the non-diabetic group), lower EQ-5D scores (0.67 for the diabetic group compared with 0.74 for the non-diabetic group), higher ODI or NDI scores (32.1 points for the diabetic group compared with 26.8 points for the non-diabetic group), and higher NRS scores (5.1 points for the diabetic group compared with 4.3 points for the nondiabetic group) (p < 0.05 for all). Although patients with diabetes improved significantly over time, they did not improve to the extent that patients without diabetes did in the ODI or NDI and EQ-5D scores (p < 0.05). Diabetes and preoperative opioid use were independent predictors of decreased SF-12 scores, decreased EQ-5D scores, increased ODI or NDI scores, and increased NRS scores (p < 0.05). Diabetes was associated with increased ODI or NDI (by 6.6 points) and decreased EQ-5D (by 0.1) at two years. Perioperative blood glucose control did not predict outcomes at either one or two years in patients with diabetes. Conclusions: Diabetes was associated with worse patient-reported outcomes when patients with diabetes were compared with patients without diabetes at two years following elective spine surgery. Although patients with diabetes improved when compared from baseline to the time following elective spine surgery, they did not improve to the same extent as patients without diabetes in the ODI or NDI and EQ-5D scores. Providers may use this information to counsel patients with diabetes on expectations following spine surgery.