Association Between Median Household Income and Perioperative Outcomes of Lumbar Spinal Fusion: An Analysis of the National Inpatient Sample (2009-2020)

<black square> BACKGROUND: Relationships between low socioeconomic status and surgical outcomes are well established for certain procedures. However, scant literature has focused on relationships between median household income and lumbar fusion outcomes. <black square> METHODS: Patients who underwent fusion procedures between January 1, 2009 and December 31, 2020 were identified from the National Inpatient Sample database. They were categorized into 4 quartiles, from lowest to highest, based on median household incomes in respective zip codes. We applied univariable and multivariable linear and logistic regression models to analyze perioperative data according to income quartiles. <black square> RESULTS: We included 2,826,396 patients. In multivariable regression, patients in the 3 lowest income quartiles exhibited higher rates of in-hospital cardiac events perioperatively, with odds ratios (ORs) of 1.19 (95% confidence interval [CI]1.13-1.26, P < 0.001), 1.10 (95% CI 1.05-1.16, P < 0.001), and 1.06(95% CI 1.01-1.12, P = 0.011) for the first, second, and third quartiles, respectively. Patients in the lowest income (first) quartile had a higher occurrence of perioperative urinary complications (OR = 1.07, 95% CI 1.03-1.12, P = 0.001), systemic infectious complications (OR = 1.17,95% CI 1.04-1.32, P = 0.006), neurological deficit (OR = 1.17, 95% CI 1.06-1.30, P = 0.002), and wound infections (OR = 1.22,95% CI 1.12-1.34, P < 0.001). Those in the 3 lowest income quartiles were less likely to experience respiratory, gastrointestinal, and venous thrombotic complications (P < 0.05). The lowest income quartile had protective associations for dural tears (OR 0.93,95% CI 0.89- 0.99, P = 0.038) and postprocedure anemia across all3 lower quartiles, with OR < 1 and P < 0.001. <black square> CONCLUSIONS: Reduced household income significantly affected perioperative outcomes after lumbar fusion and should be taken into consideration during the perioperative period.