In-hospital mortality is associated with high NT-proBNP level

Objective
To compare in-hospital mortality in unselected adult patients according to N-terminal pro-brain natriuretic peptide (NT-proBNP) levels.
Method
Retrospective study including 3833 adult patients (median age 72 years, 45% women) hospitalized between January 2013 and April 2015 in a Swiss university hospital, with at least one NT-proBNP level measurement during hospitalization. Patients were categorized in quintiles regarding their highest NT-proBNP level. In-hospital mortality and length of stay (LOS) were compared between the highest and the other quintiles.
Results
In-hospital mortality rate and LOS (average±standard deviation) were higher in the fifth quintile than in the others (6.5% vs 20.3%, and 20.8±24.0 vs. 14.9±26.5 days respectively, both p<0.001). After multivariate adjustment on age, gender, principal diagnoses, stage 5 renal failure and type of management, patients in the fifth quintile had a hazard ratio [95% confidence interval] of 1.97 [1.57–2.46] for in-hospital mortality and an adjusted LOS (average±standard error) of 20.4±1.0 vs. 14.9±0.5 days for the other quintiles (p<0.001). Further stratification on the main diagnosis at discharge led to similar findings.
Conclusion
Patients with high levels of NT-proBNP are at higher risk of in-hospital mortality and longer LOS, regardless of their clinical characteristics. NT-proBNP level can be a helpful tool for predicting in-hospital patient outcome in unselected adult patients.