Correlation of BODE Index with Diffusing Capacity of Lung for Carbon Monoxide in Assessing Disease Severity in Chronic Obstructive Pulmonary Disease

Background: Chronic Obstructive Pulmonary Disease (COPD) is the third leading cause of death globally but about 90 % of COPD mortality occurs in low- and middle-income nations. There are several studies in literature on role of BODE Index and DLCO (Diffusion capacity of carbon monoxide) as independent factors in predicting prognosis and disease severity in COPD. But there is paucity of data pertaining to relationship between BODE Index and DLCO in establishing disease severity in COPD. In this study, we intend to analyze correlation between BODE index and DLCO in patients with various stages of COPD Methods: The study was conducted as an observational, cross-sectional, study involving stable COPD patients ( diagnosed and grouped according to GOLD guidelines) of all age groups attending respiratory medicine OPD of a tertiary care hospital. The 73 patients selected were subjected to spirometery, DLCO and Six minute walk Test ( 6MWT) after taking proper history and detailed physical examination. Subsequently BODE index was calculated and patients were categorized among four quartiles of BODE index, similarly patients were also categorized based on DLCO (Mild, Moderate, Severe, Very severe). Uncategorized and categorized data on BODE index and DLCO were correlated independently various groups of GOLD classification (Group A, B, C& D). Association between various study variables was done by chi-square test. Spearman correlation coefficient was used to correlate BODE Index and DLCO. Results: Majority of patients in our study were belonging to quartile -2 of BODE score, Medium grade according to CAT score and category D according to GOLD. In our study BODE score was much better in predicting the prognosis in COPD than FEV1. BODE index was correlated well with GOLD scoring. Conclusion: Overall BODE index is accurate in categorising COPD severity. Cross tabulation with DLCO categories and GOLD categories showed better correlation compared to BODE index.