Pulmonary exercise testing predicts prognosis in patients with chronic obstructive pulmonary disease.
OBJECTIVE
In patients with chronic obstructive pulmonary disease (COPD), patient age and initial value of forced expiratory volume in 1 second (FEV1) have been considered the most accurate predictors of mortality among the parameters obtained from pulmonary exercise tests. However, few studies have examined the predictive variables of prognosis among exercise parameters in COPD. We therefore attempted to identify the best index for predicting long-term survival in patients with COPD among the cardiopulmonary variables obtained during exercise testing.


METHODS
Fifty-eight patients with COPD (50 men and 8 women) without hypoxemia at rest or other serious complications performed resting pulmonary function tests followed by a symptom-limited ramp exercise test on a cycle ergometer with breath-by-breath gas analysis and arterial blood gas sampling.


RESULTS
After 3,570+/-1,373 days follow-up (mean+/-SD), 21 died because of deaths by respiratory failure. The overall survival rates calculated by the Kaplan-Meier method were 92.9% and 75.8% at 5 years and 10 years, respectively. In univariate Cox hazards analysis, age, FEV1, VC, RV/TLC, VEmax, VO2max, VCO2max, PaO2max, PacO2max, and PaO2 at rest were found to be significant prognostic indices of survival. However, multivariate analysis revealed only FEV1, PaO2max, and age as independent predictors of mortality. In severe COPD patients (FEV1 <50% predicted, n=35), PaO2max and age also correlated with prognosis, whereas FEV1 did not.


CONCLUSIONS
Pulmonary exercise testing is useful in predicting prognosis in patients with COPD.
Tojo
Naoko
N
Departments of Clinical Laboratory Medicine, Tokyo Medical and Dental University, Tokyo.
Ichioka
Masahiko
M
Chida
Mamoru
M
Miyazato
Itsuro
I
Yoshizawa
Yasuyuki
Y
Miyasaka
Nobuyuki
N
D000368:Aged; D001784:Blood Gas Analysis; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D029424:Pulmonary Disease, Chronic Obstructive / Q000401:mortality*; D012129:Respiratory Function Tests