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Am Fam Physician. 2009;80(11):1302-1304

Background: The Severe Community-Acquired Pneumonia (SCAP) score (see accompanying table) was developed to predict clinically relevant outcomes in community-acquired pneumonia (CAP). Currently used scores such as the pneumonia severity index (PSI) and the British Thoracic Society's CURB-65 are useful for predicting pneumonia-related mortality; however, their ability to predict other clinically relevant outcomes is unknown. For instance, several studies have reported that the PSI and CURB-65 suboptimally predict the need for intensive care unit (ICU) admission. Yandiola and colleagues attempted to validate the SCAP score and to compare it to the PSI and CURB-65.

Major criteria
pH < 7.30
Systolic blood pressure < 90 mm Hg
Minor criteria
Urea > 30 mg per dL (10.71 mmol per L)
Respiratory rate > 30 beats per minute
Multilobar bilateral pneumonia on radiography
PaO2 < 54 mm Hg, or PaO2/FiO2 < 250 mm Hg
Age ≥ 80 years

The Study: The authors prospectively evaluated the three scoring systems using internal and external validation groups that included 1,860 consecutive adults hospitalized with CAP. Patients were excluded if they were chronically immunosuppressed, positive for human immunodeficiency virus infection, required recent hospitalization, or were nursing home residents. Scoring systems were evaluated for their ability to predict four adverse outcomes: ICU admission, need for mechanical ventilation, progression to severe sepsis, and treatment failure. Risk classes for PSI, CURB-65, and SCAP were assigned based on the original authors' designations.

Results: Adverse outcomes occurred in 39 percent of both validation groups and were more common in the higher-risk categories of all three scoring systems in the external validation group. Mortality rates were equivalent after adjusting for terminal conditions and age.

Being classified as high-risk according to SCAP more accurately predicted adverse outcomes than did the other scoring systems. These patients were more likely to require ICU admission (odds ratio [OR] = 9.05 for SCAP, versus 3.07 for PSI and 2.63 for CURB-65), develop severe sepsis (OR = 15.13, 6.88, and 4.16, respectively), and require mechanical ventilation (OR = 12.26, 5.63, and 2.78, respectively). All three systems were relatively inaccurate in predicting treatment failure (OR = 2.41, 1.82, and 1.32, respectively).

Conclusion: The SCAP score was as accurate or better than the PSI or CURB-65 scores in predicting adverse outcomes beyond mortality in patients hospitalized with CAP. This could be useful for identifying higher-risk patients who should be monitored more closely.

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Copyright © 2009 by the American Academy of Family Physicians.

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