Obesity and Serial NT‐proBNP Levels in Guided Medical Therapy for Heart Failure With Reduced Ejection Fraction: Insights From the GUIDE‐IT Trial

BACKGROUND: Obese patients have lower NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) levels. The prognostic implications of achieving NT‐proBNP levels ≤1000 pg/mL in obese patients with heart failure (HF) receiving biomarker‐guided therapy are not completely known. We evaluated the prognostic implications of obesity and having NT‐proBNP levels (≤1000 pg/mL) in the GUIDE‐IT (Guiding Evidence‐Based Therapy Using Biomarker‐Intensified Treatment in HF) trial participants. METHODS AND RESULTS: The risk of adverse cardiovascular events (HF hospitalization or cardiovascular mortality) was assessed using multivariable‐adjusted Cox proportional hazard models based on having NT‐proBNP ≤1000 pg/mL (taken as a time‐varying covariate), stratified by obesity status. The study outcome was also assessed on the basis of the body mass index at baseline. The predictive ability of NT‐proBNP for adverse cardiovascular events was assessed using the likelihood ratio test. Compared with nonobese patients, obese patients were mostly younger, Black race, and more likely to be women. NT‐proBNP levels were 59.0% (95% CI, 39.5%–83.5%) lower among obese individuals. The risk of adverse cardiovascular events was lower in obese (hazard ratio [HR], 0.48; 95% CI, 0.29–0.59) and nonobese (HR, 0.32; 95% CI, 0.19–0.57) patients with HF who had NT‐proBNP levels ≤1000 pg/mL, compared with those who did not. There was no interaction between obesity and having NT‐proBNP ≤1000 pg/mL on the study outcome (P>0.10). Obese patients had a greater risk of developing adverse cardiovascular events (HR, 1.39; 95% CI, 1.01–1.90) compared with nonobese patients. NT‐proBNP was the strongest predictor of adverse cardiovascular event risk in both obese and nonobese patients. CONCLUSIONS: On‐treatment NT‐proBNP level ≤1000 pg/mL has favorable prognostic implications, irrespective of obesity status. NT‐proBNP levels were the strongest predictor of cardiovascular events in both obese and nonobese individuals in this trial. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01685840.