Correlates of systolic hypertension in patients with chronic kidney disease

Abstract

Hypertension in patients with chronic kidney disease (CKD) is predominantly systolic. The contribution of risk factors for hypertension to the overall systolic blood pressure (BP) is unknown. To study the relationship between risk factors for hypertension and systolic BP in patients with CKD, 232 veterans (mean age 67 years; 96% men; 20% black; 39% with diabetes mellitus; estimated glomerular filtration rate [GFR] 48 mL/min per 1.73 m2) had clinic (routine and standardized measurements) and out-of-clinic (home and 24-hour ambulatory) BPs recorded. In multivariate analysis, using 17 risk factors, the log of the urine protein/creatinine ratio was the strongest predictor of systolic BP regardless of the BP measurement technique. The strength of the relationship between proteinuria and systolic BP was in the order ambulatory > home > standardized clinic > routine clinic BP measurement. Other independent predictors were age, race, and number of antihypertensive drugs used, and the model fit was better for out-of-clinic than clinic BP recordings. Estimated GFR was not an independent predictor of systolic BP by any technique. Nocturnal dipping was associated with higher estimated GFR, higher serum albumin, younger age, and less proteinuria. Proteinuria is the most important correlate of systolic BP in older men, the strongest relationship of which was with ambulatory and home systolic BP. Out-of-clinic BP recordings correlate better with target organ damage, as measured by proteinuria, and may be of greater clinical value than clinic BP recordings in predicting hypertension-related outcomes such as end-stage renal disease and death.