Background: We investigated the effect of having clinic and/or ambulatory blood pressures (BPs) not at goal on cardiorenal risk in patients with non-dialysis-dependent chronic kidney disease (CKD).
Study design: Multicenter prospective study.
Setting & participants: 489 consecutive hypertensive patients with CKD (stages 1-5) with concomitant assessment of ambulatory and clinic BPs followed up in tertiary nephrology clinics.
Predictors: Achievement of goal for ambulatory (day- and night-time BPs <135/85 and <120/70mmHg, respectively) and clinic (<140/90mmHg) BPs was used to create 4 BP groups: clinic and ambulatory BPs at goal (group 1), clinic BP above goal and ambulatory BP at goal (group 2), clinic BP at goal and ambulatory BP above goal (group 3), and clinic and ambulatory BPs above goal (group 4).
Outcomes: Composite cardiovascular event outcome (fatal and nonfatal myocardial infarction, congestive heart failure, stroke, revascularization, peripheral vascular disease, and nontraumatic amputation) and a composite renal outcome (maintenance dialysis therapy or death).
Measurements: Clinic and 24-hour ambulatory BPs.
Results: Mean age was 64.4±14.2 (SD) years; 41% were women, and diabetes and previous cardiovascular disease were present in 36% and 30%, respectively. Groups 1-4 contained 16.8%, 22.1%, 14.5%, and 46.6%, respectively, of the overall number of participants. Median follow-up was 5.2 years. Compared to group 1, the adjusted risk of the composite cardiovascular outcome was higher in groups 3 (HR, 3.17; 95%CI, 1.50-6.69) and 4 (HR, 2.83; 95%CI, 1.50-5.34), but not in group 2 (HR, 1.55; 95%CI, 0.75-3.19). Similarly, the risk of the composite renal outcome was higher in groups 3 (HR, 3.59; 95%CI, 2.05-6.27) and 4 (HR, 2.96; 95%CI, 1.83-4.78), but not group 2 (HR, 1.24; 95%CI, 0.67-2.27). Sensitivity analyses confirmed that these results were independent from the thresholds used for defining groups.
Limitations: Only white patients were enrolled. Observational design does not allow for causality to be established.
Conclusions: In patients with treated CKD, clinic BP above goal and ambulatory BP at goal identify a low-risk condition, whereas clinic BP at goal and ambulatory BP above goal are associated with higher cardiorenal risk, similar to that observed in patients with both clinic and ambulatory BPs above goal.
Keywords: Chronic kidney disease (CKD); ambulatory blood pressure (BP); blood pressure control; blood pressure goal; cardiorenal risk; clinic blood pressure; masked hypertension; white coat hypertension.
Copyright © 2014 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.