Severity assessment of healthcare-associated pneumonia and pneumonia in immunosuppression

The study compares the ability of the PSI (pneumonia severity index), CURB-65 (confusion, urea >7 mol-L-1, respiratory rate 330 breaths.min(-1), blood pressure <90 mmHg systolic or <= 60 mmHg diastolic, and age >= 65 yrs), CURB and CAB-65 scales and the Severe Community-Acquired Pneumonia (SCAP) score to predict 30-day mortality in healthcare-associated pneumonia (HCAP) patients, and analyses differences in the demographics, aetiology and outcomes of community-acquired pneumonia (CAP), HCAP and pneumonia in immunocompromised patients. 629 consecutive patients admitted to a tertiary care university hospital were prospectively categorised as having CAP (n=322) or HCAP (n=307), and the HCAP patients were further subdivided into those who were immunocompromised (n=219) or immunocompetent (n=88). The 30-day mortality rate was 9.0% in the CAP group and 24.1% in the HCAP group. In the HCAP group, the PSI and SCAP scores had similar prognostic power (area under the curve (AUC) of 0.68 and 0.67, respectively) and performed better than the CURB-65 score (AUC <= 0.62). Among the immunocompetent HCAP patients, the PSI and CURB-65 scores were more sensitive than the others at every threshold, whereas SCAP was more specific than both of these. In the immunocompromised group, the PSI was highly sensitive but poorly specific at all thresholds. Our results suggest that prognostic tools should be designed for subsets of HCAP patients.