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.