Correlation of cardiopulmonary exercise testing parameters with BODE index in stable chronic obstructive pulmonary disease patients

Abstract

Background Most of chronic obstructive pulmonary disease (COPD) patients show decreased exercise capacity as detected by cardiopulmonary exercise testing (CPET). The multidimensional BODE index including assessment of exercise capacity by 6-min walking distance (6MWD) can predict mortality in COPD patients. Aim To evaluate the association between CPET parameters and BODE index in stable COPD patients. Patients and methods The study included 30 stable COPD patients [mean age, 56.6±7.2 years, forced expiratory volume in the first second (FEV1%) of predicted was 40.9±18.1%]. Each studied patient underwent CPET. They had their BMI, spirometric function (forced vital capacity % and FEV1%), dyspnea score rating (using modified Medical Research Council), and 6MWD assessed. Results Positive correlations were demonstrated between BODE index and [minute ventilation (max/pred), breathing reserve, maximum oxygen consumption (VO2max) (l/min), VO2max (ml/kg/min), VO2max percentage of predicted and anerobic threshold] as r=0.395,−0.370,−0.365,−0.389, and 0.414, respectively. Furthermore, positive correlation was found between FEV1% and breathing reserve as P value less than 0.001, r=0.624. Also, 6MWD showed positive correlations with minute ventilation (max/pred), breathing reserve, VO2max (l/min), VO2max (ml/kg/min), VO2max percentage of predicted and anerobic threshold as r=−0.636, 0.429, 0.853, 0.945, 0.947, and 0.664, respectively. Conclusion The present study showed significant correlations between BODE index and different parameters of CPET.