Relation of short-term blood pressure variability to early renal effects in hypertensive patients with controlled blood pressure.

Abstract

Microalbuminuria is a common early hypertension-mediated organ damage, which correlates with the overall cardiovascular risk and development of end-stage renal damage. Lately, blood pressure variability has shown an additive value over traditional BP measurement in prediction of cardiovascular and renal involvement. Investigate the relation between short-term blood pressure variability and microalbuminuria in controlled hypertensive patients. Ninety non-diabetic hypertensive patients with controlled blood pressure and normal estimated glomerular filtration rate had 24-hour ambulatory blood pressure monitoring with calculation of short-term blood pressure variability indices (SD, coefficient of variation and average reading variability of systolic and diastolic blood pressure for 24-hour, daytime and nighttime], and measurement of the albumin/creatinine ratio. Patients were classified into group 1 (61 patients without microalbuminuria) and group 2 (29 patients with microalbuminuria). No significant difference was observed between both groups regarding age, sex, body mass index, office blood pressure, average 24-hour ambulatory blood pressure monitoring readings and dipping status, but significantly longer duration of hypertension in group 2. All blood pressure variability indices were significantly higher in group 2, which showed strong positive correlations with microalbuminuria level. Multivariate analysis represented an average reading variability of 24-hour systolic blood pressure as the most powerful independent predictor for microalbuminuria (r = 0.516, P = 0.001). Receiver operating characteristic curve analysis revealed that average reading variability of 24-hour systolic blood pressure (>12.55) could predict microalbuminuria (sensitivity = 89.7%, specificity = 88.5%, area under curve = 0.949, P = 0.001). Short-term blood pressure variability correlated well with early renal effects in controlled hypertensive patients. Average reading variability of 24-hour systolic blood pressure was the strongest predictor for microalbuminuria in such patients.