Introduction: N-terminal pro-brain natriuretic peptide (NT-proBNP) is useful in the diagnosis of heart failure. We compared NT-proBNP levels in patients with and without a diagnosis of arterial hypertension.
Patients and method: Participants were recruited from a random sample of 999 inhabitants from the Community of Valencia (eastern Spain). Of these patients, 432 said they suffered from dyspnea and were referred to their hospital (10 hospitals involved), where blood samples were taken, an echo-Doppler study was performed, and the patients completed a questionnaire. Of the 432 participants with dyspnea, 215 gave informed consent for their inclusion in the study, and 202 completed the study. Hypertension was diagnosed in 72 participants and 130 were normotensive.
Results: For the whole population, NT-proBNP, expressed as the median and range, was 88 (0-2586) pg/mL. When we compared hypertensive with normotensive participants, we found higher NT-proBNP levels in the former group: median 123, range 0-2184 pg/mL, versus median 77, range 0-2586 pg/mL (P<.01). When we excluded subjects with systolic left ventricular dysfunction, we found higher levels in participants with hypertension: 119 (0-2184 pg/mL) vs 72 (0-997 pg/mL) (P<.01). When we also excluded subjects with diastolic dysfunction, we found (median 85, range 0-430 pg/mL) and (median 66, range 0-997 pg/mL), respectively (p = NS).
Conclusion: In a population study of subjects with dyspnea, hypertensive patients have higher NT-proBNP levels than subjects with normal blood pressure. This difference disappeared when patients with diastolic dysfunction were excluded from the analysis. Hypertension can thus be a confounding factor that potentially decreases the specificity of NT-proBNP levels for the diagnosis of heart failure. These findings should be taken into account when conducting clinical and epidemiological studies in which patients with both heart failure and hypertension are included.