Interhospital transfer of critically ill patients: demographic and outcomes comparison with nontransferred intensive care unit patients.

PURPOSE: We examined the association between access to intensive care services and mortality in a cohort of critically ill patients.

MATERIALS AND METHODS: We conducted an observational study involving 6298 consecutive admissions to the intensive care units (ICUs) of a tertiary care hospital. Data including demographics, admission source, and outcomes were collected on all patients. Admission source was classified as "transfer" for patients admitted to the ICU from other hospitals, "ER" for patients admitted from the emergency room, and "ward" for patients admitted from non-ICU inpatient wards.

RESULTS: Transfer patients had higher crude ICU and hospital mortality rates compared with emergency room admissions (crude odds ratio [OR], 1.51; 95% confidence interval [CI], 1.32-1.75). After adjusting for age, sex, diagnosis, comorbidities, and acute physiology scores, the difference in ICU mortality remained significant (OR, 1.30; 95% CI, 1.09-1.56); however, hospital mortality did not (OR, 1.19; 95% CI, 1.00-1.41). Compared with ward patients, transfer from other hospitals was associated with lower hospital mortality after adjusting for severity of illness and other case-mix variables (OR, 0.81; 95% CI, 0.68-0.95).

CONCLUSIONS: We found some evidence to suggest that differential access to intensive care services impacts mortality within this case mix of patients. These findings may have implications for current efforts to centralize and regionalize critical care services.