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. 2012:5:583-9.
doi: 10.2147/IJGM.S33628. Epub 2012 Jul 12.

Blood urea nitrogen to serum albumin ratio independently predicts mortality and severity of community-acquired pneumonia

Motoi Ugajin  1 , Kenichi Yamaki, Natsuko Iwamura, Takeo Yagi, Takayuki Asano
Affiliations

Blood urea nitrogen to serum albumin ratio independently predicts mortality and severity of community-acquired pneumonia

Motoi Ugajin et al. Int J Gen Med. 2012.

Abstract

Background: Early studies of community-acquired pneumonia showed that nonsurvivors had higher blood urea nitrogen levels and lower serum albumin levels than survivors. Therefore, elevation of the blood urea nitrogen to serum albumin (B/A) ratio may identify patients with community-acquired pneumonia who are becoming critically ill. This study investigated the correlation between commonly used laboratory markers, in particular the B/A ratio, and clinical outcomes of community-acquired pneumonia.

Methods: This observational study was performed in consecutive patients with community-acquired pneumonia admitted to our hospital over a period of one year. Blood counts, commonly used laboratory markers, microbiological tests, and calculation of Pneumonia Severity Index (PSI) and CURB-65 were done on admission. The endpoints were mortality within 28 days of admission and requirement for intensive care.

Results: One hundred and seventy-five patients with community-acquired pneumonia were enrolled. Nineteen patients died within 28 days of admission and 29 patients required intensive care. Using multivariate analysis, independent factors associated with mortality were the requirement for intensive care (odds ratio [OR] 14.96, 95% confidence interval [CI] 3.73-60.03, P < 0.001), PSI class (OR 3.55, 95% CI 1.08-11.66, P = 0.037), and B/A ratio (OR 1.10, 95% CI 1.01-1.20, P = 0.037). Similarly, independent factors associated with need for intensive care were PSI class (OR 5.35, 95% CI 1.90-15.06, P = 0.002), CURB-65 (OR 2.37, 95% CI 1.26-4.45, P = 0.007), and B/A ratio (OR 1.27, 95% CI 1.09-1.47, P = 0.002).

Conclusion: The B/A ratio is a simple but independent predictor of mortality and severity of community-acquired pneumonia.

Keywords: CURB-65; Pneumonia Severity Index; blood urea nitrogen to serum albumin ratio; community-acquired pneumonia; mortality; severity.

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Figures

Figure 1
Figure 1
Analysis of receiver-operating characteristics curve for predicting mortality. The area under the curve was 0.83 for B/A ratio, 0.82 for PSI class, 0.81 for CURB-65, and 0.55 for CRP. Abbreviations: B/A ratio, blood urea nitrogen to serum albumin ratio; PSI, Pneumonia severity index; CRP, C-reactive protein.
Figure 2
Figure 2
Analysis of receiver-operating characteristics curve for predicting need for intensive care. The area under the curve was 0.86 for B/A ratio, 0.86 for PSI class, 0.84 for CURB-65, and 0.58 for CRP. Abbreviations: B/A ratio, blood urea nitrogen to serum albumin ratio; PSI, Pneumonia severity index; CRP, C-reactive protein.
See this image and copyright information in PMC

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