Treatment biases in traumatic neurosurgical care: a retrospective study of the Nationwide Inpatient Sample from 1998 to 2009

Abstract

Object: This study was designed to assess the relationship between insurance status and likelihood of receiving a neurosurgical procedure following admission for either extraaxial intracranial hemorrhage or spinal vertebral fracture.

Methods: A retrospective analysis of the Nationwide Inpatient Sample (NIS; 1998-2009) was performed. Cases of traumatic extraaxial intracranial hematoma and spinal vertebral fracture were identified using International Classification of Diseases, Ninth Revision (ICD-9) diagnosis codes. Within this cohort, those patients receiving a craniotomy or spinal fusion and/or decompression in the context of an admission for traumatic brain or spine injury, respectively, were identified using the appropriate ICD-9 procedure codes.

Results: A total of 190,412 patients with extraaxial intracranial hematoma were identified between 1998 and 2009. Within this cohort, 37,434 patients (19.7%) received a craniotomy. A total of 477,110 patients with spinal vertebral fracture were identified. Of these, 37,302 (7.8%) received a spinal decompression and/or fusion. On multivariate analysis controlling for patient demographics, severity of injuries, comorbidities, hospital volume, and hospital characteristics, uninsured patients had a reduced likelihood of receiving a craniotomy (odds ratio [OR] 0.76, 95% confidence interval [CI] 0.71-0.82) and spinal fusion (OR 0.67, 95% CI 0.64-0.71) relative to insured patients. This statistically significant trend persisted when uninsured and insured patients were matched on the basis of mortality propensity score. Uninsured patients demonstrated an elevated risk-adjusted mortality rate relative to insured patients in cases of extraaxial intracranial hematoma. Among patients with spinal injury, mortality rates were similar between patients with and without insurance.

Conclusions: In this study, uninsured patients were consistently less likely to receive a craniotomy or spinal fusion for traumatic intracranial extraaxial hemorrhage and spinal vertebral fracture, respectively. This difference persisted after accounting for overall injury severity and patient access to high- or low-volume treatment centers, and potentially reflects a resource allocation bias against uninsured patients within the hospital setting. This information adds to the growing literature detailing the benefits of health reform initiatives seeking to expand access for the uninsured.

Keywords: CI = confidence interval; ICD-9 = International Classification of Diseases, Ninth Revision; ICISS = ICD-based Injury Severity Score; LOC = loss of consciousness; NIS = Nationwide Inpatient Sample; OR = odds ratio; extraaxial intracranial hematoma; socioeconomic; spinal vertebral fracture; surgical outcomes research; trauma.