Aims: We aimed to evaluate the impact of glycometabolic imbalance as assessed by glycosylated haemoglobin [HbA(1c)] on neurohormonal activation and outcome in chronic heart failure (CHF).
Methods and results: Nine hundred and twenty CHF patients (65 ± 12 years, left ventricular ejection fraction 33 ± 10%, 29% diabetic patients) underwent a thorough humoral and clinical characterization, including HbA(1c), and were then followed up for the endpoint of cardiac death. In the whole population, diagnosis of diabetes resulted in no difference in neurohormonal or echocardiographic data, or in outcome. Conversely, the diabetic patients with HbA(1c) above 7% showed, in comparison to both diabetic patients with HbA(1c) below 7% and non-diabetic individuals, higher plasma renin activity (1.81, 0.48-5.68 vs. 1.23, 0.43-2.8 and 1.29, 0.44-5 ng/ml/h, respectively; P < 0.01 for both), N-terminal pro-brain natriuretic peptide (NT-pro-BNP) (1602, 826-3498 vs. 1022, 500-3543 and 1134, 455-3545 ng/l, respectively; P < 0.01 for both) and worse symptoms with a higher rate of cardiac mortality vs. both diabetic patients with HbA1(c) below 7% and non-diabetic individuals (P < 0.05 for both). In the left ventricular ejection fraction 38-50% tertile (mild left ventricular dysfunction), elevated HbA(1c) was associated with higher NT-pro-BNP and PRA (P < 0.01), and, alongside NT-pro-BNP, resulted the only independent predictor of outcome beyond diagnosis of diabetes. HbA(1c) failed to show up differences in neuroendocrine activation or in outcome in moderate and severe left ventricular dysfunction tertiles.
Conclusion: Glycometabolic imbalance, as represented by HbA(1c), is associated with neurohormonal activation and poor prognosis in CHF patients, beyond diabetes. The impact of metabolic derangement on prognosis appears greater at the early stages of CHF, when it might exacerbate neurohormonal activation.