Correlation of cardiopulmonary exercise testing parameters with quality of life in stable COPD patients.
BACKGROUND
The precise head to head relationships between Cardio-pulmonary exercise testing (CPET) parameters and patients' daily symptoms/activities and the disease social/emotional impact are less well defined. In this study, the correlation of COPD daily symptoms and quality of life [assessed by St. George's Respiratory Questionnaire (SGRQ)] and COPD severity index (BODE-index) with CPET parameters were investigated.


METHODS
Symptom-limited CPET was performed in 37 consecutive COPD (GOLD I-III) subjects during non-exacerbation phase. The SGRQ was also completed by each patient.


RESULTS
SGRQ-score correlated negatively with FEV1 (r=-0.49, P<0.01), predicted maximal work-rate (%WR-max) (r=-0.44, P<0.01), V'O2/WR (r=-0.52, P<0.01) and breathing reserve (r=-0.50, P<0.01). However it did not correlate with Peak-V'O2% predicted (r=-0.27, P=0.10). In 20 (54.1%) subjects in which leg fatigue was the main cause for stopping the test, Peak-V'O2, %WR-max, HR-Reserve and Breathing reserve were higher (P=0.04, <0.01, 0.04 and <0.01 respectively) than the others. There was also a significant correlation between BODE-index and ∆VO2/∆WR (r=-0.64, P<0.001) and breathing-reserve (r=-0.38, P=0.018).


CONCLUSIONS
The observed relationships between CPET parameter and daily subjective complaints in COPD were not strong. Those who discontinued the CPET because of leg fatigue were in the earlier stages of COPD. Significant negative correlation between ∆VO2/∆WR and BODE-index suggests that along with COPD progression, regardless of negative past history, other comorbidities such as cardiac/musculoskeletal problems should be sought.
Thoracic Research Center, Tehran University of Medical Sciences, Tehran, Iran ;
Mahsa
M
Mirdamadi
Thoracic Research Center, Tehran University of Medical Sciences, Tehran, Iran ;
Besharat
B
Rahimi
Thoracic Research Center, Tehran University of Medical Sciences, Tehran, Iran ;
Enayat
E
Safavi
Thoracic Research Center, Tehran University of Medical Sciences, Tehran, Iran ;
Hamidreza
H
Abtahi
Thoracic Research Center, Tehran University of Medical Sciences, Tehran, Iran;; Department of Internal Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Soheil
S
Peiman
Chronic obstructive pulmonary disease (COPD); cardio-pulmonary exercise testing (CPET); exercise capacity; quality of life; ventilatory efficiency