Prognostic value of B-type natriuretic peptide for nursing- and healthcare-associated pneumonia and aspiration pneumonia in comparison with procalcitonin and A-DROP score: a prospective cohort study.

Abstract

Pneumonia in elderly patients who require nursing care is becoming more and more common among the aging populations of developed countries, and treatment is an important topic worldwide. A simpler prognostic indicator would be expected to improve the treatment of pneumonia. This single-center, prospective cohort study aimed to compare the usefulness of B-type natriuretic peptide (BNP), procalcitonin (PCT), and the A-DROP score, which have been reported to correlate with pneumonia prognoses, such as aspiration pneumonia (AP). We included patients who were admitted to the Kanazawa Medical University Himi Municipal Hospital with a diagnosis of either nursing- and healthcare-associated pneumonia (NHCAP) or AP between January 1, 2012 and July 31, 2019. We collected demographic, clinical, and laboratory characteristics and outcome data from electronic medical records, and calculated A-DROP scores. The primary outcome was 30-day mortality. We evaluated correlations with the primary outcome using the chi-square test, Fisher exact test, t-test, Cox-regression analysis, and receiver operating characteristic curve analysis. Of the 1,215 patients with pneumonia, 297 were eligible for the study, of whom 37 (12%) died whin 30 days. After univariate analysis, we performed Cox proportional-hazards analysis for BNP, PCT, A-DROP score, albumin, C-reactive protein, and disseminated intravascular coagulation, which were significantly correlated with the primary outcome in univariate analysis. As a result, only BNP showed a significant correlation (P=0.008, 95% CI: 1.30-6.06). No significant correlation was obtained in PCT (P=0.529) and A-DROP score (P=0.107). Furthermore, we generated receiver operating characteristic curve to estimate the prognostic cut-off values of BNP for the primary outcome of NHCAP and AP. The optimal cut-off value of BNP for predicting death was 179.3 pg/mL (sensitivity 62.2%, specificity 76.2%, negative likelihood ratio 0.50%, positive likelihood ratio 2.61%). And, BNP yielded the highest area under the curve (0.72) in comparison with PCT (0.67) and A-DROP score (0.69). BNP may be a more clinically useful prognostic factor for NHCAP and AP than PCT or A-DROP score, and should be considered as a routine test at the beginning of these treatments.