Comparison of GOLD classification and modified BODE index as staging systems of COPD

Objective: To compare GOLD classification of COPD versus the modified BODE index as staging systems of COPD. Background: Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation. The degree of airflow limitation was poorly predictive of dyspnea and quality of life. The BODE index was the first multidimensional assessment system for COPD. Cardiopulmonary exercise testing (CPET) is the most comprehensive, and correlates best with the symptoms of COPD. In this regard, two novel mBODE indices were constructed by replacing 6MWT with V̇O2 peak expressed either as the percentage of predicted values (mBODE%) or as the absolute values in ml/min/kg (mBODE). Methods: This study included 28 patients with a wide range of severities of COPD. Cardiopulmonary exercise test and pulmonary functions were done. GOLD spirometric staging and combined assessment grouping were calculated then compared with the two mBODE indices. Results: Moderate agreement between the GOLD combined assessment grouping and GOLD spirometric staging systems and between mBODE and mBODE% in stratifying severity of COPD patients was observed. Evaluation of mBODE index as predictors of severity of COPD using GOLD spirometric staging as a diagnostic predictor of COPD revealed that mBODE index was 100% sensitive. However, 59.1% and 72.2% specificity were found for mBODE V̇O2ml/min/kg and mBODE V̇O2% predicted, respectively. Conclusion: Multidimensional staging system taking into account the exercise pulmonary function tests is better than unidimensional systems based on the resting pulmonary function tests only. Therefore this suggests the need for integration of the novel multidimensional approach in the diagnostic guidelines of COPD