From the Guidelines
There is a link between pro BNP elevation and obesity in acute Congestive Heart Failure (CHF), with obese patients tend to have lower levels of BNP and NT-proBNP.
Key Points
- Obese patients with HF have lower levels of BNP and NT-proBNP, which may be due to a defect in NP secretion or clearance receptors in adipose tissue 1.
- The diagnostic accuracy of BNP and NT-proBNP is reduced in obese patients, making it more challenging to diagnose HF in this population 1.
- Adjustment of cut-off values for BNP and NT-proBNP is recommended in obese patients to improve diagnostic accuracy, with lower cut-points suggested for patients with a BMI >35 kg/m2 1.
- Obesity is associated with lower levels of BNP and NT-proBNP, thereby reducing their diagnostic sensitivity 1.
- The use of BNP and NT-proBNP in clinical trials should take into account the impact of obesity on their levels, with consideration of lowering enrollment thresholds by at least 20%-30% for patients with BMI ≥30 kg/m² 1.
Clinical Implications
- Clinicians should be aware of the potential for lower BNP and NT-proBNP levels in obese patients with HF, and consider alternative diagnostic approaches or adjusted cut-off values to improve diagnostic accuracy.
- The use of BNP and NT-proBNP in risk stratification and management of HF should take into account the patient's BMI and potential impact on biomarker levels.
- Further research is needed to fully understand the relationship between obesity, BNP, and NT-proBNP in HF, and to develop more effective diagnostic and therapeutic strategies for this population.
From the Research
Relationship Between Pro BNP Elevation and Obesity in Acute Congestive Heart Failure (CHF)
- The relationship between pro BNP elevation and obesity in acute CHF is complex, with studies suggesting that obesity is associated with lower B-type natriuretic peptide (BNP) levels in patients with acute CHF 2, 3, 4.
- A study published in the American Heart Journal found that median NT-proBNP and BNP levels decreased with increasing body mass index (BMI) in patients with acute CHF, suggesting a BMI-related defect in natriuretic peptide secretion 2.
- Another study published in the Journal of the American College of Cardiology found that BNP levels were significantly lower in overweight and obese patients with advanced systolic HF compared to lean patients, despite elevated BNP being associated with worse symptoms and higher mortality in all BMI categories 3.
- The inverse relationship between BMI and BNP levels has been observed in other studies, including one published in Clinical Chemistry, which found that concentrations of both BNP and NT-proBNP were lower in obese patients without CHF or CKD 5.
- A study published in the International Journal of Cardiology found that BNP levels were lower in patients with acute decompensated heart failure with preserved vs. reduced ejection fraction, and decreased as BMI increased within the LVEF groups 4.
Clinical Implications
- The lower BNP levels in obese patients with acute CHF may lead to false-negative results, making it more challenging to diagnose CHF in this population 2, 3.
- The use of NT-proBNP as a diagnostic tool may be more sensitive than BNP in overweight and obese individuals, but both markers may have reduced sensitivity in these patients 2.
- The prognostic value of BNP is independent of BMI, and elevated BNP levels are associated with worse symptoms, impaired hemodynamics, and higher mortality in all BMI categories 3, 4.
Mechanisms and Pathophysiology
- The mechanisms underlying the relationship between obesity and lower BNP levels are not fully understood, but may involve changes in natriuretic peptide secretion or clearance 6.
- Adipose tissue may play a role in the regulation of natriuretic peptide levels, with some studies suggesting that natriuretic peptides can affect the quality and behavior of fatty tissue 6.