Changes of urinary albumin excretion and cardiovascular events: a meta-regression analysis of 32 randomized trials and 80,812 patients

Background: The association between Urinary Albumin Excretion (UAE) and Cardiovascular (CV) risk has been well established. However, it has been not demonstrated whether regression of UAE is associated with reduced CV risk. The aim of the current study was to evaluate the relationship between changes of UAE induced by pharmacologic therapies and CV events. Methods: The MEDLINE, Cochrane, ISI Web of Science and SCOPUS database were searched for articles about UAE until October 2012. Randomized trials assessing UAE at baseline and at the end of follow-up, enrolling more than 200 hypertensive and/or diabetic patients and reporting clinical end-points (all-cause death, Myocardial Infarction (MI), stroke and CV death) were included in the study. Meta-regression analysis was performed to test the relationship between UAE changes and clinical end-points. The influence of baseline patients' characteristics, follow-up, study publication year, Detsky quality score, changes in blood pressure from baseline to the end of follow-up, degree of albuminuria, glomerular filtration rate, comorbidities and concomitant pharmacological treatments were also explored. Egger's method was used to assess publication bias. Results: 32 trials enrolling 80,812 participants were included. In meta-regression analysis, a relationship between UAE changes from baseline to end of follow-up and risk MI (change in Tau2 (t)=2.74; p Tau (p)=0.011), stroke (t=2.35; p=0.030) and CV events (including MI, stroke and CV death) (t=3.74; p=0.001) was found. Results were confirmed by sensitivity analysis. No heterogeneity among studies or publication bias were detected. Conclusions: In diabetic and/or hypertensive patients, a decrease in UAE is associated with reduced risk of MI, stroke and the composite of MI/stroke/CV death. These findings may have implications for monitoring CV risk in clinical practice.