Both Chronic Kidney Disease and Nocturnal Blood Pressure Associate with Strokes in the Elderly

BACKGROUND: Among elderly hypertensive patients, we aimed to assess the association of nocturnal blood pressure (BP) pattern on stroke; interaction of dipping pattern with kidney disease was explored. METHODS: We retrospectively analyzed the records of 1,276 elderly (≥60 years) hypertensive Japanese patients (mean 74 years; 40% were men) who had measurements of estimated glomerular filtration rate and ambulatory BP. RESULTS: Stroke events occurred in 73 people over an average of 3.2 years (4,026 person-years). Chronic kidney disease (CKD) at baseline (n = 634, 50%) was more prevalent in people with strokes (71%) than those without strokes (48%; p < 0.01). Both CKD and nocturnal systolic BP (SBP) increase (10 mm Hg) were independently associated with increased risk for stroke [hazard ratio (HR), 1.9; 95% confidence interval (CI), 1.1-3.1 for CKD and HR 1.2; 1.1-1.4 for SBP]. After adjustment for office SBP, a 10-mm Hg increase in nocturnal SBP was similarly associated with strokes in patients with CKD (HR 1.2; 95% CI 1.0-1.3) and those without CKD (HR 1.2; 95% CI 0.97-1.5). Although reverse dipping (nocturnal SBP ≥ daytime SBP) was associated with stroke only in patients with CKD (HR 2.1; 95% CI 1.1-4.1) and not those without CKD (HR 1.1; 95% CI 0.3-3.8), the interaction effect was not significant (p = 0.30). CONCLUSION: In elderly hypertensive patients, both high nocturnal SBP and CKD are independent risk factors for stroke.