Rethinking the association of high blood pressure with mortality in elderly adults: the impact of frailty.
BACKGROUND
The association of hypertension and mortality is attenuated in elderly adults. Walking speed, as a measure of frailty, may identify which elderly adults are most at risk for the adverse effects of hypertension. We hypothesized that elevated blood pressure (BP) would be associated with a greater risk of mortality in faster-, but not slower-, walking older adults.


METHODS
Participants included 2340 persons 65 years and older in the National Health and Nutrition Examination Survey, 1999-2000 and 2001-2002. Mortality data were linked to death certificates in the National Death Index. Walking speed was measured over a 20-ft (6 m) walk and classified as faster (≥ 0.8 m/s [n = 1307]), slower (n = 790), or incomplete (n = 243). Potential confounders included age, sex, race, survey year, lifestyle and physiologic variables, health conditions, and antihypertensive medication use.


RESULTS
Among the participants, there were 589 deaths through December 31, 2006. The association between BP and mortality varied by walking speed. Among faster walkers, those with elevated systolic BP (≥ 140 mm Hg) had a greater adjusted risk of mortality compared with those without (hazard ratio [HR], 1.35; 95% CI, 1.03-1.77). Among slower walkers, neither elevated systolic nor diastolic BP (≥ 90 mm Hg) was associated with mortality. In participants who did not complete the walk test, elevated BP was strongly and independently associated with a lower risk of death: HR, 0.38; 95% CI, 0.23-0.62 (systolic); and HR, 0.10; 95% CI, 0.01-0.81 (diastolic).


CONCLUSIONS
Walking speed could be a simple measure to identify elderly adults who are most at risk for adverse outcomes related to high BP.
College of Public Health and Human Sciences, Oregon State University, Corvallis, OR 97331, USA. Michelle.Odden@oregonstate.edu
Michelle C
MC
Odden
Carmen A
CA
Peralta
Mary N
MN
Haan
Kenneth E
KE
Covinsky
D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure; D015986:Confounding Factors, Epidemiologic; D005260:Female; D016330:Frail Elderly; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000401:mortality / Q000503:physiopathology; D008297:Male; D009026:Mortality; D009749:Nutrition Surveys; D010809:Physical Fitness; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D016138:Walking
D000959:Antihypertensive Agents