Identification of three exercise-induced mortality risk factors in patients with COPD.
COPD
; 11(6): 615-26, 2014 Dec.
Article
em En
| MEDLINE
| ID: mdl-24914923
ABSTRACT
The survival rate of chronic obstructive pulmonary disease (COPD) patients with severely reduced exercise capacity is extremely low. We recently identified three life-threatening pathophysiological conditions during cardiopulmonary exercise testing (CPET) (1) exercise-induced hypoxemia, (2) sympathetic overactivity, and (3) progressive respiratory acidosis at low-intensity exercise. The present prospective observation study aimed to determine whether these parameters constitute risk factors of mortality in moderate-to-very severe COPD. Ninety-six COPD patients were followed-up, monthly, for >3 years. Subsequently, spirometry and CPET were performed to examine parameters of exercise-induced hypoxemia ([PaO2 slope, mmHg/L · min(-1)] = Decrease in PaO2/ΔVË O2 (Difference in ΔVË O2 between at rest and at peak exercise)), progression of acidosis ([ΔpH/ΔVË O2,/L · min(-1)] = Decrease in pH/ΔVË O2), and sympathetic overactivity ([Δnorepinephrine (NE)/ΔVË O2, ng/mL/L · min(-1)] = Increase in NE/ΔVË O2). Univariate analysis revealed a significant association between the three conditions with increased mortality. Kaplan-Meier analysis showed that the quartile combining the steepest PaO2 slope (≤-55 mmHg/ΔVË O2 [L/min]), steepest decrease in arterial blood pH (≤ -1.72/ΔVË O2 [L/min]), and most rapid increase in plasma NE level (≥ 5.2 ng/VO2 [L/min]) during incremental exercise was associated with higher all-cause mortality. These conditions showed cumulative effects on COPD patients' survival. Multivariate analyses revealed that these three life-threatening factors are also independent predictors of mortality based on age, heart rate and PaO2 at rest, body mass index, and forced expiratory volume in 1 s. Thus, these new exercise-induced mortality risk factors may lead to more efficient pulmonary rehabilitation programs for COPD patients based on patient-specific exercise-induced pathophysiological profiles.
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Base de dados:
MEDLINE
Assunto principal:
Exercício Físico
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Tolerância ao Exercício
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Doença Pulmonar Obstrutiva Crônica
Tipo de estudo:
Diagnostic_studies
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Etiology_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article