Considering the large intraindividual variability of UAE excretion, assessment of significant changes should be performed carefully. One recommended way to evaluate changes over time is to define regression when UAE drops more than 50 % from the initial values, along with a reduction of UAE to <30 mg/24 h for microalbuminurics and <300 mg/24 h for proteinurics.

Despite their relevance as a marker of developing organ damage and cardiovascular risk, changes in UAE over time, other than short-term ones induced by antihypertensive treatment, have received little attention. One study has analyzed factors related to the occurrence of new microalbuminuria during antihypertensive treatment [10]. In mild hypertensives, development of microalbuminuria was linked to insufficient BP control and to a progressive increment of glucose values. However there is less information about the long-term changes in initially increased UAE. According to our data, antihypertensive treatment is able to normalize microalbuminuria in half of the patients, although 10 % progress to overt proteinuria despite treatment. Glomerular filtration rate lower than 60 mL/min/1.73 m² decreases the probability to reduce UAE [11].

A significant reduction in proteinuria is a marker of treatment success and is followed by a reduction in the risk to develop end-stage renal disease and cardiovascular events. Whether or not changes in UAE overtime have prognostic value and can be used as an intermediate objective, it is a matter of discussion. Post hoc analyses from the Losartan Intervention for Endpoint Reduction in Hypertension (LIFE) [12], Action in Diabetes and Vascular Disease (ADVANCE) [13–15], Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET), and Telmisartan Randomized Assessment Study In ACE-Intolerant Subjects with Cardiovascular Disease (TRASCEND) have reported positive results in terms of a reduction in UAE being followed by risk reduction [16]. However, Avoiding Cardiovascular Events through Combination Therapy in Patients Living with Systolic Hypertension (ACCOMPLISH) [17] does not confirm the potential prognostic value. Likewise, a prospective study, Olmesartan for the Delay or Prevention of Microalbuminuria in Type 2 Diabetes (ROADMAP) [18], also reported no association between changes in microalbuminuria and cardiovascular events during the double-blind period, although an observational follow-up concluded that the development of microalbuminuria was a marker of cardiovascular events [19]. These studies, which were heterogeneous in terms of patients and analysis of data, did not contribute to the clarification of the potential role of microalbuminuria during antihypertensive treatment. A recent study [20] carried out in a hypertensive clinic demonstrated for first time that, in hypertension, an increment of UAE at any time is a marker of cardiovascular risk. The study also confirms previous observations regarding the prognostic value of microalbuminuria in the risk to develop cardiovascular events and the worse prognosis of persistent or progression to microalbuminuria during treatment.