Validation of predictive rules and indices of severity for community acquired pneumonia

Abstract

Background: A study was undertaken to validate the modified American Thoracic Society (ATS) rule and two British Thoracic Society (BTS) rules for the prediction of ICU admission and mortality of community acquired pneumonia and to provide a validation of these predictions on the basis of the pneumonia severity index (PSI). Method: Six hundred and ninety six consecutive patients (457 men (66%), mean (SD) age 67.8 (17.1) years, range 18-101) admitted to a tertiary care hospital were studied prospectively. Of these, 116 (16.7%) were admitted to the ICU. Results: The modified ATS rule achieved a sensitivity of 69% (95% CI 50.7 to 77.2), specificity of 97% (95% CI 96.4 to 98.9), positive predictive value of 87% (95% CI 78.3 to 93.1), and negative predictive value of 94% (95% CI 91.8 to 95.8) in predicting admission to the ICU. The corresponding predictive indices for mortality were 94% (95% CI 82.5 to 98.7), 93% (95% CI 90.6 to 94.7), 49% (95% CI 38.2 to 59.7), and 99.5% (95% CI 98.5 to 99.9), respectively. These figures compared favourably with both the BTS rules. The BTS-CURB criteria achieved predictions of pneumonia severity and mortality comparable to the PSI. Conclusions: This study confirms the power of the modified ATS rule to predict severe pneumonia in individual patients. It may be incorporated into current guidelines for the assessment of pneumonia severity. The CURB criteria may be used as an alternative tool to PSI for the detection of low risk patients.

Comparison of Severity Scoring Systems in Community-Acquired Pneumonia

“…In some studies, the need for IRVS was found to be 27%-37% within the low risk classes of PSI (classes I-III) (33)(34)(35)(36). In our study, no requirement for IRVS was observed in PSI classes I-III and the low risk group of SMART-COP (<3 points), but one patient in CURB-65 group 1 and four patients in group 2 were followed-up in the ICU.…”

Predicting mortality with pneumonia severity scores: importance of model recalibration to local settings

“…Only class I of the recalibrated PSI score can therefore be used to identify patients who qualify for outpatient management. Prior validation studies have prospectively evaluated severity scores in different clinical settings and reported high mortality rates particularly in patients of PSI class III or above and CURB65 class 1 or above [10][11][12][13][14][15][16][17]. These studies, however, focused mainly on the overall discriminatory ability of the prediction rules with varying results as expressed by differences in the area under the ROC curves.…”

“…With only few exceptions [10], external validation studies of pneumonia severity scores have focused on discriminative properties, i.e. the ability of the score to distinguish patients with CAP and fatal outcome from those surviving [10][11][12][13][14][15][16][17]. Despite good discriminatory abilities, most validation studies found higher mortality rates of patients with PSI class III and CURB65 class 1 than was reported in the original studies.…”

The impact of a delay in intensive care unit admission for community-acquired pneumonia

“…The mortality for this group of patients is extremely high and ranges 20-50% in some studies [6]. Although the Infectious Disease Society of America (IDSA) and the American Thoracic Society (ATS) issued guidelines in 2007 which recommended that patients with severe CAP be promptly admitted to the ICU [1], onethird to a half of such patients are in fact first transferred from the emergency department (ED) to the general wards [7,8]. Part of the problem is that while patients who require emergent mechanical ventilation and/or vasopressors (defined by the IDSA/ATS as major criteria for severe CAP) and hence direct ICU admission may easily be identified [2], clinical findings at the ED which suggest a rapidly progressive pneumonia are often more subtle.…”