Abstract 2748: Relationship Between Chronic Kidney Disease And Nocturnal Blood Pressure Dipping Status: A Predictor Of Cardiovascular Events In Japanese Elderly Hypertensives
Background: Non-dippers (sleep/awake systolic BP rate>0.90) in ambulatory BP is reported to have an increased risk for cardiovascular events. Chronic kidney disease (CKD) can cause non-dipper. We evaluated cardiovascular risk in elderly hypertensives with/without CKD in relation to different nocturnal BP dipping status.
Methods: We performed ambulatory BP monitoring and evaluated the estimated glomerular filtration rate (eGFR) (Cockcroft-Gault equation) in 811 older hypertensive patients (clinic BP≥140/90 mmHg and age≥50 years old) at baseline. CKD was defined as eGFR<60 ml/min. Cardiovascular events were evaluated during the follow-up period.
Results Prevalence of CKD in each dipping status at baseline was as follows: non-dippers 73.3 %, dippers 56.0 %, and extreme-dippers (sleep/awake systolic BP rate<0.80) 50.9 % (P<0.001). During the follow-up period (average 41 ± 14 months, person-year: 2799), 66 patients had cardiovascular events (59 stroke events and 11 myocardial infarction events). In Cox regression analysis, non-dippers and extreme-dippers had an increased risk for cardiovascular events [non-dippers: hazard ratio (HR) 2.44, 95 % confidence interval (CI) 1.35– 4.40, P = 0.003, extreme-dippers: HR 1.98, 95 %CI 0.98 – 4.00, P = 0.058]; however, after adjustment for confounding factors including CKD, the risk of non-dipper reduced, and that of extreme-dipper increased [non-dippers: HR 1.79, 95%CI 0.98 –3.26, P = 0.058, extreme-dippers: HR 2.56, 95 %CI 1.25–5.26, P=0.010, presence of CKD: HR 2.19, 95%CI 0.89 – 4.91, P=0.057]. Extreme-dippers with CKD (HR 6.74, 95%CI 1.45–31.38, P=0.031), extreme-dippers without CKD (HR 4.36, 95%CI 0.79 –24.06, P=0.090), and non-dippers with CKD (HR 5.21, 95%CI 1.16 –23.49, P=0.015) had a higher risk of cardiovascular events in comparison with dippers without CKD, even after adjustment for known confounding factors, while the risk of non-dippers without CKD was not significant (P=0.42).
Conclusions Patients with CKD have an increased risk of cardiovascular events regardless of dipping status. When taking account of presence of CKD, the cardiovascular risk of non-dippers reduce and that of extreme-dipper increase.