50. Lower neighborhood socioeconomic status influences medical complications, emergency department utilization and costs after 1-2 level lumbar fusion

BACKGROUND CONTEXT

Socioeconomic status (SES) has been demonstrated to be an important prognostic factor among patients undergoing spine surgery. Measures of socioeconomic disadvantage may enable improved targeting of measures to prevent and recognize potential increased healthcare utilization in these disadvantaged patients. The Area Deprivation Index (ADI) is a validated and weighted index comprised of 17 census-based markers of material deprivation and poverty.

PURPOSE

The purpose of this study was to utilize a large nationwide administrative claims database to determine whether patients with high ADI (greater disadvantage) undergoing 1-2 level lumbar fusion (LF) is associated with differences in: 1) medical complications; 2) emergency department (ED) utilization; 3) readmission rates; and 4) costs of care.

STUDY DESIGN/SETTING

A retrospective query of all primary 1-2 level lumbar fusions for degenerative lumbar pathology was performed using a large United States private insurance claims database from January 1st, 2010 to October 31st, 2020.

PATIENT SAMPLE

Cohorts of interest were queried using Current Procedural Terminology (CPT) codes and International Classification of Disease, Ninth/Tenth Revision (ICD-9), ICD-10 codes. ADI is reported on a scale of 0-100 with higher numbers associated with greater disadvantage. Percentile was documented for each zip code for all states. The study group consisted of patients undergoing primary LF in zip codes associated with high ADI (90%+) as established by previously published studies. The control cohort consisted of LF patients who underwent surgery in zip codes not defined by the study group (0-89%). Patients with high ADI were 1:1 propensity score matched to controls by age, gender, and Elixhauser Comorbidity Index (ECI). This yielded 34,442 patients in total, evenly matched between the two cohorts.

OUTCOME MEASURES

Primary endpoints of the study were to compare 90-day medical complications, 90-day ED utilization, 90-day readmission rates, and 90-day costs of care.

METHODS

Multivariable logistic regression models were used to calculate the odds-ratios (OR) and 95% confidence intervals (95%CI) of ADI on 90-day medical complications, ED utilization, and readmission rates. A Shapiro-Wilks test was performed to assess for normality of distribution followed by Welch's T tests for the continuous variables lengths of stay and costs. P-values less than 0.05 were considered to be statistically significant.

RESULTS

Patients undergoing 1-2 level LF with a high ADI incurred significantly higher rates and odds of developing respiratory failures (1.17 vs 0.87%; OR: 1.35, 95%CI: 1.09 - 1.67, p=0.005). The remaining medical complications including pneumonia (2.60 vs 2.55%; OR: 1.02, 95%CI: 0.89 - 1.16, p=0.785), acute kidney injuries (2.61 vs 2.29%; OR: 1.14, 95%CI: 0.99 - 1.31, p=0.056), deep venous thrombosis (0.19% vs 0.17%; OR: 1.14, 95%CI: 0.69 - 1.89, p=0.611), cerebrovascular accidents (1.29% vs 1.31%; OR: 0.99, 95%CI: 0.82 - 1.19, p=0.886), and overall total medical complications (23.35% vs 22.93%; OR: 1.02, 95%CI: 0.97 - 1.08, p=0.441) were similar between groups. Despite lower rates of readmissions in patients with a high ADI versus controls (8.43% vs 9.13%; OR: 0.92, 95%CI: 0.85-0.99, p=0.021), high ADI patients had significantly higher rates and odds of ED visits within 90 days (9.67% vs 8.91%; OR: 1.10, 95%CI: 1.02- 1.18, p=0.014). Overall day of surgery ($49,878 vs $42,886) and 90-day expenditures ($54,459 vs $47,044) were greater in patients from a high ADI (p<0.001).

CONCLUSIONS

Socioeconomically disadvantaged patients have increased rates and odds of 90-day respiratory failures. ED utilization within 90 days of surgery was higher in socioeconomically disadvantaged patients (high ADI) despite lower readmission rates. Measures of neighborhood disadvantage, including the ADI, could potentially be used to inform healthcare policy and improve post-discharge care.

FDA Device/Drug Status

This abstract does not discuss or include any applicable devices or drugs.