The impact of neighborhood socioeconomic disadvantage on short term postoperative outcomes following lumbar spinal fusion in a Medicare-insured patient population

Introduction: Over the past decade, there has been a significant increase in lumbar spinal fusion surgeries performed. This increase coincides with the aging U.S. population and the number of procedures performed is expected to continue to increase. There is a growing body of literature establishing a relationship between poor surgical outcomes and living in socioeconomically disadvantaged neighborhoods using the area-deprivation index (ADI). However, few studies to date have examined that relationship in Medicare patients undergoing lumbar fusion and short term postoperative outcomes.

Methods: Adult patients undergoing first time inpatient lumbar spinal fusion surgeries from 2006 to 2018 were identified from the Medicare 20% sample dataset. ADI were determined based on the patient’s zip code. Patients were segmented based on their ADI, with the bottom 85% composed of one segment and then the top 15% split into three groups of 5%. Regression analysis was performed for several surgical outcomes variables including length of stay, length of intensive care stay, 30 day complication, 30 day readmission, and 30 day mortality.

Results: 168,816 patients met inclusion criteria and were included in the analysis. The average age of our cohort was 69±10 years and a majority were female (59%). Patients in the highest ADI segment were associated with increased length of stay (Coeff. 0.38, 95% CI 0.28-0.49), increased length of ICU stay (Coeff. 0.24, 95% CI 0.17-0.30) and increased odds of having 30 day complications (OR 1.12, 95% CI 1.06-1.19), 30 day readmission (OR 1.09, 95% CI 1.02-1.17), and 30 day mortality (OR 1.4, 95% CI 1.15-1.7).

Conclusion : Medicare patients from socioeconomic disadvantaged neighborhoods have worse short term postoperative outcomes following lumbar spinal fusion. These findings were observed after controlling for comorbidity, hospital setting and racial differences.