Statistical analysis of pneumonia severity scoring systems

January 01, 0001

Statistical analysis of pneumonia severity scoring systems

Various scoring systems have been used to predict mortality in cases of community-acquired pneumonia. These UK researchers searched MEDLINE and EMBASE for prospective studies reporting mortality in cases of radiographically-confirmed community-acquired pneumonia. They looked specifically at the Pneumonia Severity Index (PSI) and the versions of the CURB (confusion, urea nitrogen, respiratory rate, blood pressure) scale know as CURB-65, CURB, CRB-65). Random effects meta-analysis determined test performance and receiver operating characteristic curves were used for predicting mortality.

The researchers report: "402 articles were screened and 23 studies involving 22?753 participants (average mortality 7.4%) were retrieved. The respective diagnostic odds ratios for mortality were 10.77 (PSI), 6.40 (CURB- 65), 5.97 (CRB-65) and 5.75 (CURB). Overall, PSI had the highest sensitivity and lowest specificity for mortality, CRB-65 was the most specific (but least sensitive) test and CURB-65/CURB were between the two. Negative predictive values for mortality were similar among the tests, ranging from 0.94 (CRB-65) to 0.98 (PSI), whereas positive predictive values ranged from 0.14 (PSI) to 0.28 (CRB-65)."

The researchers concluded: "The current risk stratification scales (PSI, CURB-65, CRB-65 and CURB) have different strengths and weaknesses. All four scales had good negative predictive values for mortality in populations with a low prevalence of death but were less useful with regard to positive predictive values."

This meta-analysis finds pneumonia severity scores are most useful to identify patients at low mortality risk.

For the full abstract, click here.

Thorax 65(10):884-890, October 2010
© 2010 BMJ Publishing Group Ltd & British Thoracic Society
Value of severity scales in predicting mortality from community-acquired pneumonia: systematic review and meta-analysis -- Loke et al. --. Yoon K Loke, Chun Shing Kwok, Alagaratnam Niruban, Phyo K Myint. Correspondence to Yoon K Loke:

Category: R. Respiratory. Keywords: community acquired pneumonia, severity, Pneumonia Severity Index, CURB scale, mortality, systematic review with meta-analysis, journal watch.
Synopsis edited by Dr Paul Schaefer, Toledo, Ohio. Posted on Global Family Doctor 8 October 2010

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