Blood pressure components and decline in kidney function in community-living older adults: The cardiovascular health study

Abstract

Background Although hypertension contributes to kidney dysfunction in the general population, the contributions of elevated systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure (PP) to kidney function decline in community-dwelling older adults are unknown. Methods We used linear and logistic regression to examine the separate and combined associations of SBP, DBP, and PP at baseline with kidney function decline among 4,365 older adults in the Cardiovascular Health Study. We used cystatin C to estimate glomerular filtration rate on 3 occasions over 7 years of follow-up. We defined rapid decline = 3 ml/min/year. Results Average age was 72.2 and mean (standard deviation) SBP, DBP, and PP were 135 (21), 71 (11), and 65 (18) mm Hg, respectively. SBP and PP, rather than DBP, were most significantly associated with kidney function decline. In adjusted linear models, each 10-mm Hg increment in SBP and PP was associated with 0.13 ml/min/year (-0.19, -0.08, P > 0.001) and 0.15-ml/min/year faster decline (-0.21, -0.09, P > 0.001), respectively. Each 10-mm Hg increment in DBP was associated with a nonsignificant 0.10-ml/min/year faster decline (95% confidence interval, -0.20, 0.01). In adjusted logistic models, SBP had the strongest associations with rapid decline, with 14% increased hazard of rapid decline (95% confidence interval, 10% to 17%, P > 0.01) per 10 mm Hg. In models combining BP components, only SBP consistently had independent associations with rapid decline. Conclusions Our findings suggest that elevated BP, particularly SBP, contributes to declining kidney function in older adults. © American Journal of Hypertension, Ltd 2013.