Relationship between Ambulatory BP and Clinical Outcomes in Patients with Hypertensive CKD

Background and objectives Abnormal ambulatory BP (ABP) profiles are commonplace in CKD, yet the prognostic value of ABP for renal and cardiovascular outcomes is uncertain. This study assessed the relationship of baseline ABP profiles with CKD progression and subsequent cardiovascular outcomes to determine the prognostic value of ABP beyond that of clinic BP measurements. Design, setting, participants, & measurements Between 2002 and 2003, 617 African Americans with hypertensive CKD treated to a clinic BP goal of <130/80 mmHg were enrolled in this prospective, observational study. Participants were followed for a median of 5 years. Primary renal outcome was a composite of doubling of serum creatinine, ESRD, or death. The primary cardiovascular outcome was a composite of myocardial infarction, hospitalized congestive heart failure, stroke, revascularization procedures, cardiovascular death, and ESRD. Results Multivariable Cox proportional hazard analysis showed that higher 24-hour systolic BP (SBP), daytime, night-time, and clinic SBP were each associated with subsequent renal (hazard ratio, 1.17-1.28; P<0.001) and cardiovascular outcomes (hazard ratio, 1.22-1.32; P<0.001). After controlling for clinic SBP, ABP measures were predictive of renal outcomes in participants with clinic SBP <130 mmHg (P<0.05 for interaction). ABP predicted cardiovascular outcomes with no interaction based on clinic BP control. Conclusions ABP provides additional information beyond that of multiple clinic BP measures in predicting renal and cardiovascular outcomes in African Americans with hypertensive CKD. The primary utility of ABP in these CKD patients was to identify high-risk individuals among those patients with controlled clinic BP. Clin J Am Soc Nephrol 7: 1770-1776, 2012. doi: 10.2215/CJN.11301111