The Social Deprivation Index and Lumbar Spine Surgery Outcomes

Introduction: The Social Deprivation Index (SDI) measures area-level social disadvantage. SDI values range from zero (no distress/prosperous) to 100 (highest distress). The association between SDI and lumbar spine surgery outcomes has not been studied. This study aims to explore that relationship.

Methods: A retrospective cross-sectional study was performed using electronic health record data from a multi-hospital, academic health system from 2017 to 2024. Eligible patients included adults who underwent lumbar fusion or decompression alone. The primary exposure of interest was the binary SDI (low distress: SDI < 50 vs. high distress: SDI >=50 & SDI <=100). The SDI was associated with the patient’s Zone Improvement Plan (ZIP) code of residence. The association between the SDI category and pain reduction, physical function improvement, length of stay, and 30-day readmission was examined. Both unadjusted and adjusted regression models were created. Adjusted models included the following covariates: age, comorbidities, race, insurance, and surgery type. Multiple imputation by chained equations was used to impute missing values.

Results: The total sample included 7,598 patients with 5,139 in the low SDI group and 2,459 in the high SDI group. SDI category was not significantly associated with the likelihood of pain reduction or physical function improvement following surgery. In the adjusted model, residence in a high SDI area was significantly associated with extended length of stay (odds ratio (OR) 1.21, 95% confidence interval (CI) 1.07 – 1.36, p = 0.002). In the unadjusted model, patients from high SDI areas were significantly more likely to experience 30-day readmission (OR 1.35, 95% CI 1.07 – 1.71, p = 0.01). In the adjusted model, this association was no longer statistically significant (OR 1.00, 95% CI 0.74 – 1.36, p = 1.00).

Conclusion : Patients from high SDI areas had similar pain and physical function outcomes compared to patients from low SDI areas following lumbar spine surgery. High SDI was significantly associated with length of stay. This study highlights the need for interventions that address the unique needs of patients from low-resource settings to improve lumbar spine surgery outcomes.