1543. Diabetes is Predictive of Postoperative Outcomes and Readmission Following Posterior Lumbar Fusion

Authors: Annie Arrighi-Allisan; Sean Neifert, BS; Jeffrey Zimering, MD; Jonathan Gal; Brian Deutsch, BS; Daniel Snyder, BS; John Caridi, MD (New York, NY)

Introduction: Posterior lumbar fusion (PLF) is performed to treat numerous spinal pathologies. The literature exploring the effect of diabetes mellitus (DM) on outcomes in spine surgery, however, yields conflicting results. The present study compares complication rates and episode-based costs for patients with and without DM following PLF. Methods: PLF cases at a single institution from 2008-2016 were queried (n=3169), and demographic and perioperative data were analyzed. Patients with and without the diagnosis of DM were compared using chi-square, Student’s t-test, and multivariable regression modeling. Results: Patients with diabetes were significantly sicker (68.29% of patients had ASA Class >2 vs. 28.46%, P <0.0001), older (62.98 vs. 56.48 years, P <0.0001), and possessed a greater number of preoperative comorbidities (20.32% of patients had Elixhauser score >0 vs. 11.46%, P <0.0001) than non-diabetic patients. When controlling for preexisting differences, diabetes remained a significant risk factor for a prolonged length of stay (OR=1.36, 95% CI: 1.08 – 1.72, P =0.01), 30-day readmission (OR=1.92, 95% CI: 1.2 – 3.10, P =0.007), 90-day readmission (OR=1.65, 95% CI: 1.09 – 2.50, P =0.02), 30-day ER visit (OR=2.13, 95% CI: 1.29 – 3.53, P =0.003), and 90-day ER visit (OR=2.03, 95% CI: 1.29–3.19, P =0.002). Diabetic patients were significantly more likely to experience renal failure (3.05% vs. 1.20%, P =0.002), myocardial infarction (2.44% vs. 1.27%, P =0.046), pneumonia (3.25% vs. 1.46%, P =0.005), and sepsis (0.81% vs. 0.19%, P =0.04) than were non-diabetic patients. Cost modeling demonstrated that diabetes was associated with a $2,059 increase in PLF costs (CI: $388-$3,730, P =0.02); however, this effect did not endure when controlling for overall comorbidity burden. Conclusion: The present findings indicate a correlation between diabetes and a multitude of postoperative adverse outcomes, thus illustrating the substantial medical and financial burdens of diabetes for PLF patients. Future studies should explore preventive measures that may mitigate these downstream effects.