Impact of Interhospital Transfer in Mortality of Critically Ill Patients

ABSTRACT

PURPOSE: Interhospital transfer of critically ill patients is often necessary for optimal patient care. However it is known that transport of critically ill patients has been associated with high rate of potentially detrimental complications. This study was designed to determine whether mortality of critically ill patients with interhospital transfers is different from critically ill patients with direct admissions. METHODS: The retrospective cohort study was conducted at an academic medical center with 3906 critically ill patients from 2003 to 2004, of whom 1652 were direct admissions and 2254 were interhospital transfers. Death within 48 hours in interhospital transfers and direct admissions were compared using univariate and multivariate regression analyses that adjusted for severity of illness. Severity of illness was measured using Simplified Acute Physiology Score (SAPS) II and Charles comorbidity score. To measure hospital performance standardized mortality ratio (SMR) was calculated by dividing observed mortality by SAPS II-predicted mortality. RESULTS: Death within 48 hours were not significantly higher for interhospital transfer patients than for directly admitted patients (7.5% vs 8.1%, p<0.05). But directly admitted patients had significantly higher SMR than transferred patients (0.94 vs 0.81, p=0.001). Finally, transferred patients with hepatic failure had significantly higher mortality rates (odds ratio=4.636) as compared with directly admitted patients, confirming the "transfer effect"for this patients' subgroup. CONCLUSION: Admission source is not an important determinant of outcome.