Association of poor physical function and cognitive dysfunction with high nocturnal blood pressure level in treated elderly hypertensive patients

Background Our aim was to assess the association between poor physical function, cognitive dysfunction, and high nocturnal systolic blood pressure (SBP), all of which are markers of vulnerability or frailty in elderly persons.MethodsIn this cross-sectional study of 148 treated ambulatory elderly hypertensives (mean age: 75.5 years; 30% men), we evaluated 24-h BP levels, physical function (walking speed and timed up-and-go (TUG) tests), and mini-mental state examination (MMSE). Poor physical function or cognitive dysfunction was defined as a walking speed 1.5m/s or MMSE score 27 points (below the geometric means for either examination).ResultsBoth slower walking speed and lower MMSE scores were associated with high nocturnal SBP level, but not with daytime SBP level, even after adjustment for significant covariates (P = 0.05 and P 0.01, respectively). Slower walking speed was significantly associated with the diminished nocturnal SBP dipping independent of the 24-h BP levels (P = 0.02). Compared with the patients who performed well on both physical and cognitive tests, or with those who had either poor physical function or cognitive dysfunction but not both, patients with both poor physical function and cognitive dysfunction had significantly higher nocturnal SBP levels (120 vs. 123 vs. 128 vs. 134mmHg; P = 0.008 for linear trend) and less marked nocturnal SBP dipping (14.4 vs. 12.9 vs. 10.7 vs. 7.5%; P = 0.02 for linear trend) even after adjustment for significant covariates.ConclusionPoor physical function and/or cognitive dysfunction could be valid markers likely to be associated with high nocturnal SBP, information which could help yield more refined prognosis for treated elderly hypertensives.