Insurance Coverage Predicts Mortality in Patients Transferred Between Hospitals: a Cross-Sectional Study.

Abstract

Patients transferred between hospitals are at high risk of adverse events and mortality. The relationship between insurance status, transfer practices, and outcomes has not been definitively characterized. To identify the association between insurance coverage and mortality of patients transferred between hospitals. We conducted a single-institution observational study, and validated results using a national administrative database of inter-hospital transfers. Three ICUs at an academic tertiary care center validated by a nationally representative sample of inter-hospital transfers. The single-institution analysis included 652 consecutive patients transferred from 57 hospitals between 2011 and 2012. The administrative database included 353,018 patients transferred between 437 hospitals. Adjusted inpatient mortality and 24-h mortality, stratified by insurance status. Of 652 consecutive transfers to three ICUs, we observed that uninsured patients had higher adjusted inpatient mortality (OR 2.67, p = 0.021) when controlling for age, race, gender, Apache-II, and whether the patient was transferred from an ED. Uninsured were more likely to be transferred from ED (OR 2.3, p = 0.026), and earlier in their hospital course (3.9 vs 2.0days, p = 0.002). Using an administrative dataset, we validated these observations, finding that the uninsured had higher adjusted inpatient mortality (OR 1.24, 95% CI 1.13-1.36, p < 0.001) and higher mortality within 24h (OR 1.33 95% CI 1.11-1.60, p < 0.002). The increase in mortality was independent of patient demographics, referral patterns, or diagnoses. This is an observational study where transfer appropriateness cannot be directly assessed. Uninsured patients are more likely to be transferred from an ED and have higher mortality. These data suggest factors that drive inter-hospital transfer of uninsured patients have the potential to exacerbate outcome disparities.