Urinary Albumin To Creatine Ratio Is An Independent Predictor Of Prognosis Of Heart Failure

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Main Category: Cardiovascular / Cardiology
Also Included In: Heart Disease;  Medical Devices / Diagnostics
Article Date: 17 Aug 2009 - 0:00 PDT

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An article in this week's issue of The Lancet reports that the ratio of albumin to creatine in a person's urine is a dominant and independent predictor of prognosis of heart failure. The article is the work of Professor John J V McMurray, British Heart Foundation Cardiovascular Research Centre, University of Glasgow, UK, and collaborators.

It is documented that increased excretion of albumin in urine is a risk factor for mortality, cardiovascular events, and kidney disease in the general population, and in patients with diabetes, high blood pressure, and other types of cardiovascular disease. The authors aimed in this study to measure the prognostic value of a spot urinary albumin to creatine ratio (UACR) in patients with heart failure. They used data from the Candersartan in Heart failure: Assessment of Reduction in Mortality and morbidity (CHARM) Programme.

A total of 2,310 patients were included in the study and during follow-up. Patients were diagnosed with very high albumin excretion (macroalbuminuria), less serious excretion (microalbuminuria) or normal excretion (normoalbuminuria). Results showed that 58 percent of patients had normal UACR, 30 percent had microalbuminuria, and 11 percent had macroalbuminuria. The incidence of increased UACR was comparable in patients with reduced and preserved left ventricular ejection fractions, which is a measure of heart function. Patients with increased UACR were older, had more cardiovascular disease, inferior kidney function, and a higher prevalence of diabetes than did those with normoalbuminuria.

On the other hand, a high prevalence of UACR was still noted in heart failure patients without diabetes, high blood pressure, or kidney disease. Higher UACR was linked with increased risk of death from cardiovascular causes or admission to hospital with deteriorating heart failure. Those are the combined end point of the CHARM study. This was true even after adjustment for kidney function, and diabetes/blood glucose status. Patients with microalbuminuria were 43 percent more likely to reach the combined end point than those with normal UACR. Patients with macroalbuminuria were 75 percent more likely to reach the combined end point than those with regular UACR. When assessing particularly death due to cardiovascular causes, patients with microalbuminuria were 62 percent more likely to die from this cause than those with normal UACR. This probability rose to 76 percent for patients with macroalbuminuria.

The authors write in conclusion: "Increased UACR is a powerful and independent predictor of prognosis in heart failure…Because UACR is a simple, readily available clinical test that is widely used in primary and secondary care, it might be of value in risk stratification of patients with heart failure…Of Potential interest to physicians and patients is whether therapeutic reduction in albumin excretion, which did not occur with candesartan, might be useful in the prediction of improvement in clinical outcomes."

In an associated note, Dr Kevin Damman, Dr Hans L Hillege, and Dr Dirk J van Veldhuisen, Department of Cardiology, University Medical Center Groningen, Netherlands, mention: "The role of albuminuria in heart failure deserves further attention and today's CHARM substudy offers a first glimpse into the relation between albuminuria and outcome, which seems in accordance with observations in the general population and other populations of patients…New prospective studies should answer the question of whether treatment of albuminuria can improve survival or at least, preserve kidney function in patients with heart failure."

"Albuminuria in chronic heart failure: prevalence and prognostic importance"
Colette E Jackson, Scott D Solomon, Hertzel C Gerstein, Sofia Zetterstrand, Bertil Olofsson, Eric L Michelson, Christopher B Granger, Karl Swedberg, Marc A Pfeffer, Salim Yusuf, John J V McMurray for the CHARM Investigators and Committees
Lancet 2009; 374: 543-50
The Lancet

Written by Stephanie Brunner (B.A.)
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