NPPB and susceptibility to pneumonia measurement: A clinical history of cardiac failure was associated with higher NT-proBNP values and was a significant predictor of 30-day mortality in age-adjusted analysis (OR = 3.5, 95% CI = 3.4 to 17.9, p = 0.005), but was a weaker predictor than NT-proBNP and was of borderline statistical significance in analyses adjusted for both NT-proBNP and the Pneumonia Severity Index (OR 2.2, 95% CI, 0.9 to 5.5, p = 0.081).