Albuminuria in chronic heart failure: prevalence and prognostic importance

BACKGROUND: Increased excretion of albumin in urine might be a marker of the various pathophysiological changes that arise in patients with heart failure. Therefore our aim was to assess the prevalence and prognostic value of a spot urinary albumin to creatinine ratio (UACR) in patients with heart failure. METHODS: UACR was measured at baseline and during follow-up of 2310 patients in the Candesartan in Heart failure: Assessment of Reduction in Mortality and morbidity (CHARM) Programme. The prevalence of microalbuminuria and macroalbuminuria, and the predictive value of UACR for the primary composite outcome of each CHARM study--ie, death from cardiovascular causes or admission to hospital with worsening heart failure--and death from any cause were assessed. FINDINGS: 1349 (58%) patients had a normal UACR, 704 (30%) had microalbuminuria, and 257 (11%) had macroalbuminuria. The prevalence of increased UACR was similar in patients with reduced and preserved left ventricular ejection fractions. Patients with an increased UACR were older, had more cardiovascular comorbidity, worse renal function, and a higher prevalence of diabetes mellitus than did those with normoalbuminuria. However, a high prevalence of increased UACR was still noted among patients without diabetes, hypertension, or renal dysfunction. Elevated UACR was associated with increased risk of the composite outcome and death even after adjustment for other prognostic variables including renal function, diabetes, and haemoglobin A1c. The adjusted hazard ratio (HR) for the composite outcome in patients with microalbuminuria versus normoalbuminuria was 1.43 (95% CI 1.21-1.69; p<0.0001) and for macroalbuminuria versus normoalbuminuria was 1.75 (1.39-2.20; p<0.0001). The adjusted values for death were 1.62 (1.32-1.99; p<0.0001) for microalbuminuria versus normoalbuminuria, and 1.76 (1.32-2.35; p=0.0001) for macroalbuminuria versus normoalbuminuria. Treatment with candesartan did not reduce or prevent the development of excessive excretion of urinary albumin. INTERPRETATION: Increased UACR is a powerful and independent predictor of prognosis in heart failure. FUNDING: AstraZeneca.