Prognostic importance of baseline and serial changes in microalbuminuria in patients with resistant hypertension

Abstract

ObjectiveThe prognostic value of microalbuminuria is unsettled in resistant hypertension. The objective was to evaluate the importance of baseline and serial changes in albuminuria as predictors of cardiovascular morbidity and mortality in patients with resistant hypertension. Methods531 resistant hypertensives had urinary albumin excretion rate (UAER) measured prospectively at baseline and at the 2nd year of follow-up. Primary endpoints were a composite of fatal and non-fatal cardiovascular events, all-cause and cardiovascular mortalities. Total strokes and coronary heart disease (CHD) events were secondary endpoints. Multiple Cox regression assessed the associations between UAER and endpoints. ResultsAfter a median follow-up of 4.9 years, 72 patients died, 42 from cardiovascular causes; 96 cardiovascular events occurred, 42 strokes and 47 CHD events. After adjustment for several cardiovascular risk factors, baseline UAER, either analyzed as a continuous variable or dichotomized at different cut-off values, was an independent predictor of the composite endpoint, all-cause and cardiovascular mortality, strokes and CHD events. Each 10-fold increase in UAER implied a significant 1.6, 1.5, 2.0, 1.5 and 1.6-fold higher risk, respectively, for each of the above endpoints. Serial changes in microalbuminuria status during follow-up tended to parallel changes in cardiovascular risk, regression of microalbuminuria was associated with a 27% lower risk and development with a 65% higher risk of having a cardiovascular event. ConclusionsBaseline albuminuria strongly predicts cardiovascular morbidity and mortality in resistant hypertensive patients and serial changes in microalbuminuria may translate into changes in risk. Microalbuminuria reduction may be a goal of anti-hypertensive treatment.