Both chronic kidney disease and nocturnal blood pressure associate with strokes in the elderly

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.

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.

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).

In elderly hypertensive patients, both high nocturnal SBP and CKD are independent risk factors for stroke.