Sociodemographic Characteristics Predict Readmission Rates After Lumbar Spinal Fusion Surgery.

Objective To evaluate the impact of social determinants of health (race/ethnicity, household income, insurance) and hospital surgical volume on 30- and 90-day readmissions after lumbar spinal fusion surgery. Methods A retrospective review of the State Inpatient Databases (SID) Healthcare Cost and Utilization Project (HCUP) included all patients age >= 18years who underwent an index lumbar spinal fusion procedure and met inclusion criteria in California (2007-2011), Maryland (2012-2014), Florida, and New York (2007-2014). Primary outcomes were unadjusted rates and adjusted odds of readmission at 30 and 90 days postoperatively. Results After assessing for exclusion criteria, 267,976 patients were included in analyses. The overall 30-day readmission rate was 7.5%, and the 90-day readmission rate was 11.6%. Black patients (odds ratio [OR] = 1.12, 95% confidence interval [CI] = 1.06-1.19) and patients with nonprivate insurance (Medicare OR = 1.44, 95% CI = 1.37-1.51; Medicaid OR = 1.46, 95% CI = 1.36-1.56; or uninsured OR = 1.16, 95% CI = 1.00-1.35) had higher odds of 30-day readmission, with comparable effects at 90 days. The three highest quartiles of hospital lumbar spine surgical volume had decreased odds for 30- and 90-day readmission when compared with the lowest quartile. Median income had no effect on readmission rates, save for the top quartile having lower odds of 90-day readmission than the bottom quartile. Conclusions Sociodemographic disparities in primary insurance payer, race/ethnicity, and hospital surgical volume affect lumbar spinal fusion surgery readmission rates. Public health interventions may improve readmissions and clinical outcomes and reduce health care costs.