Clinical Significance of NT-proBNP in Patients with Low BNP Requiring Non-Surgical Intensive Care

Serum N-terminal pro-brain-type natriuretic peptide (NT-proBNP) and brain-type natriuretic peptide (BNP) levels are rarely evaluated simultaneously in patients requiring intensive care.A total of 4,724 patients were screened, and 1,755 patients with BNP levels < 100 pg/mL were analyzed. Patients were divided into two groups, according to the median value of the NT-proBNP/BNP ratio (low-NT-proBNP/BNP group [Group L] versus high-NT-proBNP/BNP group [Group H]). A multivariate logistic regression model showed that the C-reactive protein levels (per 1-mg/dL increase) and serum creatinine levels (per 1-mg/dL increase) were independently associated with a high NT-proBNP/BNP ratio (odds ratio: 1.251, 95% confidence interval [95% CI]: 1.172-1.335 and odds ratio: 1.941, 95% CI: 1.468-2.567, respectively). The Kaplan-Meier curve analysis showed that the prognosis was significantly poorer in Group H than in Group L. Moreover, a multivariate Cox regression model revealed that a high NT-proBNP/BNP ratio was an independent predictor of 365-day mortality (hazard ratio: 1.468, 95% CI: 1.027-2.067). The same significant trend in prognostic impact was observed in the low-creatinine (< 0.83 mg/dL, n = 883), high-creatinine (≥ 0.83 ng/dL, n = 872), and high- C-reactive protein (≥ 0.16 mg/dL, n = 842) cohorts.A high NT-proBNP/BNP ratio was associated with a non-cardiac condition. Consequently, it was independently associated with adverse outcomes in patients requiring intensive care, even in those with a low BNP value on admission.