Modeling to identify patients with risk of bronchial asthma and chronic obstructive pulmonary disease overlap

Abstract

According to Russian clinical COPD guidelines (2024), 101 bronchial asthma (BA) patients were diagnosed with a possible BA and COPD overlap (32.7%). The main clinical and functional characteristics were compared in patients with BA without (BA group) and with COPD overlap (BA+COPD group). Against the background of a higher rate of pack-years indicator, severe asthma with more pronounced bronchial obstruction and reduced SpO2 levels was more common in BA+COPD group. According to the results of 6MWT in BA+COPD group, we revealed a more pronounced impairment of physical performance against the background of a more significant decrease in all main characteristics of blood oxygenation before, during and after 6MWT combined with high levels of desaturation-distance ratio (DDR) and the need for additional O2 flow during physical activity (O2-GAP index). The potential diagnostic regression model included: age, the factor of the severe asthma presence, the factor of the lack of complete control of bronchial asthma according to GINA, the DDR value, the dynamics of dyspnea as a result of 6MWT, average blood oxygenation after 6MWT, FEV1 , FVC and pack-years indicator. Three independent factors were included in the final model to accurately determine the probability of a combination of bronchial asthma and COPD: DDR, FEV1 , and pack-years indicator. The developed model has characteristics: AUC=0,88 (p<0.001), the sensitivity is 75.0%, specificity is 90.6%. The BA and COPD overlap was highly probable with the diagnostic threshold of the model ≥0.481.