Importance of Basal Metabolic Index in the Diagnosis of Heart Failure With B-Type Natriuretic Peptide

Diagnostic and prognostic considerations for use of natriuretic peptides in obese patients with heart failure

Natriuretic peptides (NPs, B-type natriuretic peptide /BNP and NT-proBNP) are universally used biomarkers with established cut-points to aid in the diagnosis of heart failure (HF). It has been demonstrated that an inverse relationship exists between obesity, defined by the body mass index (BMI), and NPs, such that the application of NPs to diagnostic algorithms in HF remains challenging in overweight and obese patients. Some have advocated that lowering the cut-offs for NPs or using a correction for high BMI may improve the diagnostic accuracy in obese individuals. The inverse relationship of NPs with high BMI is present in both HF with reduced (HFrEF) and with preserved (HFpEF) ejection fraction, although levels tend to be higher in HFrEF. Nevertheless, data from several studies have shown that the prognostic value of NPs is preserved across BMI classes, and that increasing circulating levels of NPs correlate with adverse outcomes including all-cause mortality and HF hospitalizations. While NPs can still be used in diagnosis of HF in obese individuals, lower thresholds and the clinical context should be utilized in decision making. Additionally, given the validated prognostic value even in obesity, NPs can be employed in risk-stratification of individuals with obesity and HF, although there remains limited evidence about use in those with severe obesity (BMI >40 kg/m²).