JAPAN: Elders' Exaggerated BP Variability Linked to Decline In Cognitive Function, Shows Study

NEW YORK, NY (WebMD), May 25, 2006: A new study shows that exaggerated BP variability is associated with decline in cognitive function among elderly patients over 80 years of age, a finding that suggests more aggressive antihypertensive treatment in this population may provide a cognitive benefit [1]. "Although clinicians may be reluctant to treat older patients aggressively, perhaps because of perceived lower benefits or possible increased risk of medication side effects, these findings show the potential value of interventions," said lead author Dr Kenichi Sakakura of Public Kiwa Clinic, Kumano, Mie, Japan. Dr Kenichi Sakakura The study, along with a second report from this group showing a similar relationship between pulse pressure and cognitive dysfunction [2], was presented here at the American Society of Hypertension 21st Annual Scientific Meeting and Exposition. Exaggerated BP variability BP variability is the standard deviation (SD) between high and low readings on 24-hour blood-pressure monitoring. Blood pressure is not static over the course of a day but rises during the daytime and drops at night during sleep in normal subjects. However, exaggerated BP variability has been associated with cognitive dysfunction and with aging, Sakakura and colleagues point out. Few data are available on the effect of exaggerated BP variability in the very elderly age group. The researchers looked at the relationship between BP variability in patients aged over 80 years and cognitive dysfunction. Twenty-four-hour ambulatory blood-pressure monitoring was performed in 101 Japanese patients, and the standard deviation of daytime systolic BP was calculated as a measure of BP variability. Patients were also assessed using the Mini-Mental State Examination (MMSE); on this 30-point scale, a score of less than 24 is considered diagnostic of cognitive dysfunction. Mean 24-hour BPs were 138.1+17.6/75.9+8.0 mm Hg for the group. Mean SD in daytime SBP was 21.2+4.2, and the mean MMSE score was 23.1+4.2—55.4% of patients had cognitive dysfunction. They report that cognitive functioning declined across tertiles for daytime systolic BP, with greater evidence of decline seen among patients with SBP variability in the highest tertile (22.9-33.3 mm Hg) vs those in the lowest tertile (12.1-19.5 mm Hg), p=0.006. The association remained significant after they controlled for daytime SBP level, suggesting an independent relationship between BP variability and cognitive function. At a press conference here, Sakakura speculated that long-acting blood-pressure medications that would reduce variability may modify this relationship but pointed out that further studies are required to confirm that reducing BP variability would have an effect in reducing cognitive decline in these patients. In a separate paper also presented here, Sakakura et al also showed a relationship with increasing pulse pressure—the difference between systolic and diastolic readings—and cognitive dysfunction in this same group of subjects. Mean 24-hour pulse pressure in the group was 62.1+12.7 mm Hg. They report that mean MMSE scores declined significantly across tertiles of standard deviation in 24-hour pulse pressure (p=0.012), and the association remained significant after controlling for 24-hour mean blood pressure (p=0.022). Sources Sakakura K, Ishikawa J, Okuno M, et al. The relationship between exaggerated blood pressure variability and cognitive dysfunction in the very elderly. American Society of Hypertension 21st Annual Scientific Meeting and Exposition; May 16-20, 2006; New York, NY. Abstract P-289. Sakakura K, Ishikawa J, Okuno M, et al. Increased 24-hour pulse pressure affects cognitive dysfunction in the very elderly. American Society of Hypertension 21st Annual Scientific Meeting and Exposition; May 16-20, 2006; New York, NY. Abstract P-28. By Susan Jeffrey Copyright© 1994-2006 by WebMD. All rights reserved.