2129. Utilization of Post-Discharge Antibiotics in Spinal Fusion in a Nationwide Cohort of Commercially Insured Individuals

BACKGROUND: Discontinuation of prophylactic antibiotics within 24 hours after surgery is recommended in multiple guidelines. The objective of this study was to determine the prevalence and patterns of prophylactic post-discharge antibiotic use after spinal fusion in a geographically representative, privately insured population. METHODS: We established a cohort of patients aged 10–64 years undergoing inpatient or ambulatory surgery spinal fusion between January 1, 2010–June 30, 2015 using the Truven Health MarketScan Database. Antibiotics were identified from outpatient drug claims ≤5 days post-discharge; comorbidities were assessed ≤1 year before surgery. Patients with infection during the surgical admission or ≤30 days prior were excluded. Univariate logistic regression and chi-square tests were used to compare antibiotic utilization for operative factors, demographics and comorbidities. RESULTS: The analysis included 174,202 fusion procedures, with 51.5% of surgeries involving the cervical spine, 81.3% involving 1–2 vertebral levels, and 53.05% using an anterior approach. The median patient age was 52 years and 55.3% were female. Post-discharge prophylactic antibiotics were used in 13,611 (7.8%) of surgeries, with cephalexin (39.2%) and levofloxacin (10.5%) the most commonly prescribed. Post-discharge antibiotic use decreased significantly from 2010 to 2015 (8.3% of procedures in 2010 vs. 7.7% in 2015; P < 0.001; Cochran-Armitage test), was higher in rural areas (8.8% of rural vs. 7.6% of urban/suburban patients; P < 0.001), and differed by U.S. region (8.5% South, 8.1% West, 6.9% North Central, 6.6% Northeast; P < 0.001). Patients prescribed prophylactic post-discharge antibiotics had more comorbidities including obesity, diabetes, pulmonary disease, hypertension, and psychoses (all P < 0.001). Post-discharge antibiotic use varied by surgical approach (9.6% anterior/posterior, 9.2% posterior only, 6.8% anterior only; P < 0.001) and spine region (9.4% lumbar, 6.7% cervical, 6.7% multiple regions, 6.1% thoracic; P < 0.001), and was more common when >2 vertebral levels were involved (P < 0.001). CONCLUSION: Post-discharge antibiotic prophylaxis following spinal fusion surgery was associated with geographic, operative and patient factors. DISCLOSURES: All authors: No reported disclosures.