Albuminuria in heart failure: Associated with heart failure severity and predictor of poor clinical outcome

Background: Urinary albumin to creatinine ratio (UACR) is common in patients with heart failure (HF) and may have an impact on clinical outcomes. We evaluated the effect of UACR on clinical outcomes in a real-world cohort of patients with HF.

Methods: We analyzed UACR in patients with HF at a health maintenance organization and followed for cardiac-related hospitalizations and death.

Results: The study cohort included 4,668 HF patients and was divided into 3 groups based on UACR: normal range albuminuria (2,085 patients; 45%), microalbuminuria (1,769 patients; 38%), and macroalbuminuria (814 patients; 17%). Microalbuminuria and macroalbuminuria were both associated with increasing age, diabetes mellitus, hypertension, peripheral vascular disease, atrial fibrillation, and NYHA class 3 and 4. Microalbuminuria and macroalbuminuria were directly associated with decreased event-free survival from death as well as death and cardiovascular-hospitalizations, Figure 1. Cox regression analysis after adjustment for significant predictors demonstrated that microalbuminuria was associated with an increase in mortality (hazard ratio (HR) 1.18, 95% CI 1.18-1.38, P=0.03) and macroalbuminuria (HR 1.33, 95% CI 1.10-1.61, P<0.001). Albuminuria was also an independent predictor of death and cardiovascular-hospitalizations. Analysis of albuminuria as a continuous parameter (natural logarithm transformed) showed that UACR was an independent predictor of mortality as well as death and cardiovascular-hospitalizations. Subclinical albuminuria (UACR 12-29µg/mg) was directly associated with reduced survival. Cox regression analysis using restricted cubic splines demonstrated an independent continuous increase in mortality with increasing albuminuria (P

Conclusions: Albuminuria provides important information regarding several detrimental processes in HF and is a significant predictor of a worse outcome.

Figure 1. [A]. Histogram of UACR. [B]. Kaplan Meier survival analysis. Increasing UACR levels were directly associated with reduced survival; Log-rank P<0.001. [C]. Kaplan Meier event-free survival. Increasing UACR levels were directly associated with reduced event-free survival from death or cardiovascular-hospitalizations; Log-rank P<0.001.