Low serum albumin levels occur in a variety of disease states and are related to in-hospital mortality and length of stay. The purpose of this study was to evaluate the association of commonly measured biochemical markers in critically ill patients such as serum albumin or C-reactive protein (CRP) with the need for intensive respiratory or vasopressor support (IRVS) in patients with 2009 influenza A (H1N1).


A total of 104 patients from an H1N1 registry database of 2436 patients were enrolled. Clinical characteristics and laboratory findings within 24 h of admission were reviewed to evaluate whether serum biochemical markers can be used as predictors of illness severity in adult patients with H1N1 based on the need for IRVS.


Twenty-four (23.1%) of the 104 patients enrolled in the study received IRVS during the study period. Independent predictors of the need IRVS were serum glucose level on admission (OR 1.02; 95% CI 1.00–1.04; p = 0.021) and serum albumin level on admission (OR 0.12; 95% CI 0.02–0.63; p = 0.013). The diagnostic sensitivity of albumin levels for predicting the need for IRVS in patients with confirmed H1N1 with a cut-off value of 2.7 g/dl was 79.17% (95% CI 57.8–92.9), the specificity was 85.71% (95% CI 75.9–92.6), the positive predictive value was 63.3% (95% CI 43.9–80.1) and the negative predictive value was 93.0% (95% CI 84.3–97.7). The area under the receiver operation characteristic curve was 0.860 (95% CI 0.773–0.923) for albumin, 0.808 (95% CI 0.713–0.882) for glucose and 0.734 (95% CI 0.633–0.821) for CRP.


Serum albumin levels and glucose levels on admission were predictors of the need IRVS in adult patients with H1N1. Based on these findings, the level of albumin at presentation may serve as a novel and simple early biomarker to identify patients at high risk for a complicated clinical course of disease.