Prognostic utility of N-terminal pro-B-type natriuretic peptide in adult and elderly patients with community acquired pneumonia

Objective:
N-terminal pro-B-type natriuretic peptide (NT-proBNP) is suggested as a prognostic biomarker for communityacquired pneumonia (CAP). However, its predictive value for an individual adult and elderly CAP patients has not been fully investigated.
Method:
Patients with CAP aged 18 years and older, who visited the emergency department (ED) from March 1, 2016 to March 31, 2019, were included in this study. Patients were divided into the adult group and the elderly group (age ≥70 years). Data was collected from the ED-based registry, and medical charts were retrospectively reviewed. The registry data included sociodemographic and past medical characteristics, as well as laboratory findings including NT-proBNP and C-reactive protein (CRP), Pneumonia Severity Index (PSI), and CURB65 (confusion, urea, respiratory rate, blood pressure, and aged 65 or more). The independent potential of NT-proBNP to predict mortality was assessed in both groups using multivariable logistic regression, and its predictive ability was evaluated in terms of performance (using areas under the curve [AUCs]) and goodness-of-fit (using the Bayesian information criterion [BIC]).
Results:
Totally, 325 CAP patients were evaluated, of which 208 (64%) belonged to the elderly group. NT-proBNP was identified as an independent predictor of CAP mortality in elderly patients, but not in adult patients. Moreover, AUC of the NT-proBNP for mortality was comparable to AUC of the PSI, but was higher than that of the CURB65, in elderly CAP patients. Similarly, the NT-proBNP had a better overall fit (lower BIC value) compared to the CURB65, for mortality. Additionally, both AUC and overall fit of the NT-proBNP for mortality were significantly superior to values obtained for CRP.
Conclusion:
For elderly CAP patients in the ED, the NT-proBNP is an independent and useful predictor of mortality.

Key words: Natriuretic peptides; Prognosis; Elderly; Pneumonia