Time rate of blood pressure variation is associated with impaired renal function in hypertensive patients

The rate of blood pressure (BP) variation has been positively associated with intima-media thickness of common carotid arteries and left ventricular mass. We evaluated the association between the rate of BP variation derived from ambulatory blood pressure monitoring (ABPM) data analysis and impaired renal function.

Twenty-four-hour ABPM was performed in 803 untreated hypertensive patients. The estimated glomerular filtration rate (eGFR) was assessed using the abbreviated equation of the Modification Diet for Renal Disease study. Patients were divided into two groups: those with an eGFR less than 60 ml/min per 1.73 m(2) (group A) and those with an eGFR 60 ml/min per 1.73 m(2) or more (group B).

The 24-h rate of systolic BP variation was significantly (P = 0.004) higher in group A [0.616 mmHg/min; 95% confidence interval (CI) 0.596-0.636] than in group B patients (0.585 mmHg/min; 95% CI 0.578-0.591), even after adjusting for baseline characteristics and ABPM parameters. In the entire study population, the multiple logistic regression models revealed the following variables as independent determinants of impaired renal function: age, male sex, office systolic BP and 24-h rate of systolic BP variation. In this model, the odds ratio for impaired renal function associated with each 0.1 mmHg/min increase in 24-h rate of systolic BP variation was 1.49 (95% CI 1.18-1.88, P = 0.001).

The 24-h rate of SBP variation is independently associated with impaired renal function. Target-organ damage in hypertensive patients, in addition to BP levels, dipping status and BP variability, may also be related to a steeper rate of BP fluctuations.