To assess the value of serum C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), tumor necrosis factor α (TNFα), brain natriuretic peptide (BNP) for diagnosis of community-acquired pneumonia (CAP) in patients with chronic heart failure (CHF).
Material and methods
We conducted prospective observational study in adult patients with confirmed CHF who were hospitalized with suspected CAP. The diagnosis of CAP was verified by chest computed tomography. Patients were distributed into group 1 (with confirmed CAP) and group 2 (without CAP but with other respiratory tract infections). Serum biomarkers were measured in all patients at admission.
Seventy eligible subjects were enrolled in our study (35 patients with verified CAP and 35 patients without CAP). Demographic and baseline clinical characteristics were comparable in the two groups. In group 1, serum CRP, PCT and IL-6 levels were significantly higher than in group 2. ROCanalysis demonstrated excellent efficacy to predict CAP in CHF for CRP (AUC=0,91, 95% CI 0,83-0,98) and good efficacy for PCT (AUC=0,81, 95% CI 0,72-0,90) and IL-6 (AUC=0,81, 95% CI 0,71-0,91). However, sensitivity of PCT and IL-6 was low. CRP level of >28,5 mg/L, which had a sensitivity of 85,7% and a specificity of 91,4%, was considered as optimal threshold to verify CAP in concomitant CHF (positive predictive value of 90,9% and negative predictive value of 86,4%).
Serum CRP level (with cutoff >28,5 mg/L) can be useful for differential diagnosis of CAP and other respiratory tract infections in patients with CHF, while diagnostic value of PCT, IL-6, TNFα and BNP was not confirmed.
Serum biomarkers, inflammation, communityacquired pneumonia, chronic heart failure, diagnosis.