Clinical correlates of ambulatory BP monitoring among patients with CKD.

Background And Objectives: Ambulatory BP monitoring (ABPM) allows a better risk stratification than office BP in hypertensive patients. However, the clinical relevance of ABPM has not been extensively investigated in the CKD population.

Design, Setting, Participants, & Measurements: Within the Chronic Kidney Disease Japan Cohort study, 2977 patients enrolled (62% men, aged 60.8±11.6 years) and ABPM was conducted in a subgroup of patients from September 2007 to April 2010. Data from 1075 patients (682 men) were analyzed to determine BP control and factors associated with the ABPM parameters.

Results: The prevalence of masked hypertension was 30.9%, whereas that of white-coat hypertension was 5.6%. With advancing CKD stage, the percentage of persistent hypertension increased from 21.7% to 36.1%. Diabetes, antihypertensive medicine use, and low estimated GFR (eGFR) were significantly associated with the difference between office BP and ambulatory BP (1.7 mmHg, 2.6 mmHg, and 0.6 mmHg per 10 ml/min per 1.73 m(2), respectively). There tended to be fewer nondippers and risers in stage 3 than in stages 4 and 5. In the nocturia-negative group, low eGFR, diabetes, and summer season were identified as factors associated with lower nocturnal BP change (-0.5 mmHg, -2.0 mmHg, and -2.8 mmHg, respectively). Morning BP change was greater with older age (0.2 mmHg per 10 years) and higher body mass index (0.6 mmHg per 1 kg/m(2)), and in winter (4.5 mmHg) versus summer.

Conclusions: Various factors including eGFR, diabetes, antihypertensive medication use, and season are associated with higher BP and abnormal BP patterns in CKD patients.