Relationship of age and exercise performance in patients with heart failure: the HF-ACTION study.
BACKGROUND
More than three fourths of patients with heart failure (HF) are 65 years and older, and older age is associated with worse symptoms and prognoses than is younger age. Reduced exercise capacity is a chief HF complaint and indicates poorer prognosis, especially among elderly persons, but the mechanisms underlying functional decline in older patients with HF are largely unknown.


METHODS
Baseline cardiopulmonary exercise testing data from the HF-ACTION trial were assessed to clarify age effects on peak oxygen consumption (VO(2)) and ventilation-carbon dioxide production (VE/VCO(2)) slope.


RESULTS
Among 2,331 New York Heart Association class II-IV patients with HF, increased age corresponded to decreased peak VO(2) (-0.14 mL kg(-1) min(-1) per year >40 years; P < .0001) and increased VE/VCO(2) slope (0.30 U/y >70 years; P < .0001). In a multivariable model with 34 other potential determinants, age was the strongest independent predictor of peak VO(2) (partial R(2) 0.130, total R(2) 0.392; P < .001) and a significant but relatively weaker predictor of VE/VCO(2) slope (partial R(2) 0.037, total R(2) 0.199; P < .001). Blunted peak heart rate was also a strong predictor of peak VO(2). Although peak heart rate and age were strongly correlated, both were significant independent predictors of peak VO(2) when analyzed simultaneously in a model. Aggregate comorbidity increased significantly with age but did not account for age effects on peak VO(2).


CONCLUSIONS
Age is the strongest predictor of peak VO(2) and a significant predictor of VE/VCO(2) slope in the HF-ACTION population. Age-dependent comorbidities do not explain changes in peak VO(2). Age-related changes in cardiovascular physiology, potentially magnified by the HF disease state, should be considered a contributor to the pathophysiology and a target for more effective therapy in older patients with HF.
Forman
Daniel E
DE
Cardiovascular Division, Brigham and Women's Hospital, and Geriatric Research, Education, and Clinical Center (GRECC), VA Boston Healthcare System, Boston, MA, USA.
Clare
Robert
R
Kitzman
Dalane W
DW
Ellis
Stephen J
SJ
Fleg
Jerome L
JL
Chiara
Toni
T
Fletcher
Gerald
G
Kraus
William E
WE
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology; D002245:Carbon Dioxide / Q000378:metabolism; D003625:Data Collection / Q000706:statistics & numerical data; D015444:Exercise / Q000502:physiology; D005080:Exercise Test / Q000706:statistics & numerical data*; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D011379:Prognosis; D012123:Pulmonary Ventilation / Q000502:physiology; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology
D002245:Carbon Dioxide