Prognostic impact of baseline urinary albumin excretion rate in patients with resistant hypertension: a prospective cohort study

Moderately increased albuminuria, defined as urinary albumin excretion rate (UAER) between 30 and 300 mg/24 h is a well-known cardiovascular risk factor, especially in diabetic and hypertensive patients. This study aim to analyze the prognostic value of baseline UAER in a still understudied group, patients with resistant hypertension (RHT). This is a prospective observational study, which had enrolled 1048 outpatients with RHT, who were submitted to a clinical-laboratory assessment and ambulatory blood pressure monitoring (ABPM) during the follow-up. Primary endpoints were a composite of fatal and non-fatal cardiovascular events, all-cause mortality and cardiovascular mortality. Survival analysis by multiple Cox regression assessed the associations among endpoints, baseline UAER, glomerular filtration rate (GFR), and ABPM control. After a mean 7.5 years follow-up, 233 patients died, 120 from cardiac death; 215 cardiovascular events occurred, 90 strokes and 116 coronary diseases. UAER above 30 mg/24 h increased above 40% the risk of fatal and non-fatal cardiovascular events, and of all-cause mortality. At these UAER levels, secondary outcomes were associated to increased risk of stroke and risk of end-stage renal disease, but did not affect coronary events. Both the GFR below 60 mL/min and uncontrolled ABPM were related to nearly two-fold raised risk of fatal and non-fatal cardiovascular events, when coupled with UAER above 30 mg/24 h. In conclusion, moderately increased albuminuria predicts cardiovascular events and all-cause mortality in RHT, and its prognostic impact is enhanced in association with a GFR under 60 mL/min and uncontrolled baseline ABPM.