Extremely High NT-proBNP in Unselected Hospital Admissions: A Retrospective Analysis of Diagnoses and Outcomes

Elevated N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations are commonly interpreted as suggestive of heart failure (HF) but may also occur in the context of acute systemic illness and infection.

To evaluate diagnoses and outcomes among hospitalised adults with extremely high NT-proBNP.

Retrospective cohort study.

Adult hospital admissions with NT-proBNP concentrations ≥ 20,000 pg/mL.

Clinical and laboratory data as well as primary diagnosis and all-cause mortality were recorded. Survivors and non-survivors at 6 months were compared. Overall survival was assessed using Kaplan-Meier analysis; associations with mortality were evaluated using multivariable Cox regression.

A total of 415 admissions were included. Median age was 82 years (IQR 73-88), 51.6% were male and median NT-proBNP was 35,000 pg/mL (IQR 26,563-35,000). The most common imaging findings were pulmonary congestion (55.4%) and infection (53.7%). Infection was the most common primary diagnosis (60%) and cause of death (71%), while HF was the primary diagnosis in 19%. Mortality was high: 43.6% in hospital and 64.5% at 6 months. Patients with infection had significantly higher mortality than those with other diagnoses. Cox regression showed older age and lower serum albumin were independent predictors of mortality.

In unselected hospitalised patients, extremely high NT-proBNP levels were more frequently associated with infection and high mortality than with HF. NT-proBNP values occurred across a heterogenous range of acute illnesses and should be interpreted within the wider clinical context rather than as evidence of a single disease process.