Reappearance of the J-shaped curve

Increased pulse pressure linked to dementia: further results from the Hypertension in the Very Elderly Trial - HYVET

OBJECTIVES

High blood pressure (BP) has been associated with increased risk of dementia. Concerns have been raised about lowering BP too far in the very elderly and thereby increasing risk. There is some evidence to suggest a potential 'J'-shaped relationship between DBP and risk of cognitive impairment. This was investigated using data from the HYpertension in the Very Elderly Trial (HYVET).

METHODS

HYVET was a double-blind, placebo-controlled trial of antihypertensives in patients aged at least 80 years with an untreated SBP of 160-199 mmHg. Active medication was indapamide sustained release 1.5 mg+/- perindopril 2-4 mg to reach goal pressure of less than 150/80 mmHg. Incident dementia was a secondary endpoint and was not significantly different between the two treatment groups. The relationship between pressure and incident dementia was assessed using Cox proportional hazards regression with BP entered as either a discrete (quartile analysis) or continuous predictor variable. Achieved BP was calculated as the mean of all pressures from the 9 month visit onwards.

RESULTS

During a mean follow-up of 2.2 years 263 incident cases of dementia were diagnosed. After adjustment for various covariates, baseline DBP was inversely related to incident dementia (P=0.0064). Achieved DBP did not predict later dementia in the placebo group (P=0.43), but showed a U-shaped relationship in the active treatment group (P=0.0195). The relationship between incident dementia and DBP did however not differ significantly between the placebo and active treatment groups (P=0.38). SBP was not associated with incident dementia, at baseline (P=0.62) or during follow-up (placebo group P=0.13, active group P=0.36). Wider achieved pulse pressure (PP) was associated with increased risk of dementia in both treatment groups (placebo P=0.032, active P=0.0046). The same tendency was observed for baseline PP (P=0.095).

CONCLUSION

Wider PP may possibly indicate an increased risk for dementia. Active treatment may act to change the shape of the relationship between DBP and dementia. Future studies need to focus on exploring the ideal goal pressure for this age group.

Lower standing systolic blood pressure as a predictor of falls in the elderly: a community-based prospective study

OBJECTIVES

We investigated prospectively the relationships among falls, physical balance, and standing and supine blood pressure (BP) in elderly persons.

BACKGROUND

Falls occur often and adversely affect the activities of daily living in the elderly; however, their relationship to BP has not been clarified thoroughly.

METHODS

A total of 266 community-dwelling elderly persons age 65 years or over (123 men and 143 women, mean age of 76 years) were selected from among residents of Coop City, Bronx, New York. Balance was evaluated at baseline using computerized dynamic posturography (DPG). During a one-year follow-up, we collected information on subsequent falls on a monthly basis by postcard and telephone follow-up.

RESULTS

One or more falls occurred in 60 subjects (22%) during the one-year follow-up. Women fell more frequently than men (28% vs. 16%, p < 0.03), and fallers were younger than nonfallers. Fallers (n = 60) had lower systolic BP (SBP) levels when compared with nonfallers (n = 206) (128 +/- 17 vs. 137 +/- 22 mm Hg for standing, p < 0.006; 137 +/- 16 vs. 144 +/- 22 mm Hg for lying, p < 0.02), whereas diastolic BP was not related to falls. Falls occurred 2.8 times more often in the lower BP subgroup (<140 mm Hg for standing SBP) than in the higher BP subgroup (> or =140 mm Hg, p < 0.0003), and gender-related differences were observed (p = 0.006): 3.4 times for women (p < 0.0001) versus 1.9 times for men (p = 0.30). Loss of balance, as detected by DPG, did not predict future falls and was also not associated with baseline BP levels. Multiple logistic regression analysis demonstrated that female gender (relative risk [RR] = 2.1, p = 0.02), history of falls (RR = 2.5, p = 0.008) and lower standing SBP level (RR = 0.78 for 10 mm Hg increase, p = 0.005) were independent predictors of falls during one year of follow-up.

CONCLUSIONS

Lower standing SBP, even within normotensive ranges, was an independent predictor of falls in the community-dwelling elderly. Elderly women with a history of falls and with lower SBP levels should have more attention paid to the prevention of falls and related accidents.

Diastolic pressure, systolic pressure, or pulse pressure?

Diastolic pressure, systolic pressure, and pulse pressure have all been assigned the role of the best predictor of cardiovascular events during the 20th century. At the dawn of the new millennium, concepts that draw attention to vascular mechanics reconcile the seemingly conflicting results of epidemiologic studies, better define the hypertensive patient, evaluate more accurately the risk and set its markers, and ultimately optimize treatment through a logical approach that aims at the mechanism and not at the manifestation. Pulse wave analysis and measurement of arterial stiffness are valuable tools in the assessment and management of the hypertensive patient.