Serum Albumin As an Outcome Predictor in Hospital Emergency Medical Admissions

Background: To examine the relationship between admission serum albumin and 30-day mortality during an emergency medical admission.

Methods: An analysis was performed of all emergency medical patients admitted to St. James's Hospital (SJH), Dublin between 1st January 2002 and 31st December 2008, using the hospital in-patient enquiry (HIPE) system, linked to the patient administration system, and laboratory datasets. Mortality was defined as an in-hospital death within 30 days. Logistic regression was used to calculate unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals for defined albumin subsets.

Findings: Univariate analysis using predefined criteria based on distribution, identified the groups of <10% and between 10 and 25% of the serum albumin frequency distribution as at increased mortality risk. Their mortality rates were 31.7% and 15.4% respectively; their unadjusted odds rates were 6.35 (5.68, 7.09) and 2.11 (1.90, 2.34). Patients in the lowest 25% of the distribution had a 30-day mortality of 19.9% and this significantly increased risk persisted, after adjustment for other outcome predictors including co-morbidity and illness severity (OR 2.95 (2.49, 3.48): p<0.0001).

Interpretation: Serum albumin is predictive of 30-day mortality in emergency medical patients; mortality is non-linearly related to baseline albumin. The disproportionate increased death risk for patients in the lowest 25% of the frequency distribution (<36 g/L) is not due to co-morbidity factors or acute illness severity.