NT-proBNP Cutoffs for HFpEF Diagnosis May Need Adjustments

Key Points

• Current NT-proBNP cutoffs for diagnosing heart failure with preserved ejection fraction (HFpEF) may not be optimal in outpatient settings.
• Obesity impacts NT-proBNP thresholds, requiring lower values for accurate HFpEF diagnosis.
• Atrial fibrillation (AF) itself is a strong marker of HFpEF, making NT-proBNP less useful in these patients.

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Study Findings

• Current NT-proBNP threshold of <125 pg/mL to rule out HFpEF had:
  • 77% sensitivity overall.
  • 82% sensitivity in patients with BMI < 35 kg/m².
  • 67% sensitivity in patients with BMI ≥ 35 kg/m².
• Lowering the cutoff to <50 pg/mL improved sensitivity to:
  • 97% in BMI < 35 kg/m².
  • 86% in BMI ≥ 35 kg/m².
• To rule in HFpEF, the cutoff should be:
  • ≥ 500 pg/mL for BMI < 35 kg/m² (85% specificity).
  • ≥ 220 pg/mL for BMI ≥ 35 kg/m² (88% specificity).

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Key Implications

• Current cutoffs may lead to misdiagnosis, especially in obese patients with HFpEF.
• Lower NT-proBNP values (30-50 pg/mL) may be necessary to truly rule out HFpEF.
• Nearly all AF patients in the study (98%) also had HFpEF, making NT-proBNP less helpful in diagnosing HFpEF in this group.

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Why This Matters

• HFpEF treatments are now effective, so accurate diagnosis is crucial.
• Missing HFpEF due to incorrect NT-proBNP thresholds could delay life-saving treatment.

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Call for Further Research

• New biomarkers, such as endothelin-1 and adrenomedullin, may be better for HFpEF diagnosis, as they are not affected by obesity.
• Larger, multicenter studies with invasive validation are needed to confirm findings.

This study suggests that clinicians should reconsider NT-proBNP cutoffs for HFpEF, particularly in obese patients, to improve diagnosis and treatment outcomes.