Classification of Obstructive Pulmonary Diseases Through Clinical Characteristics in a Prospective Cohort Study.

Introduction: The use of clinical characteristics to differentiate obstructive lung diseases remains unclear, with limited supporting studies. This study aims to assess the effectiveness of signs and symptoms from clinical questionnaires in diagnosing obstructive lung diseases.

Methods: This prospective cohort study included patients diagnosed with chronic obstructive pulmonary disease (COPD), asthma, or asthma-COPD overlap (ACOS) based on spirometry. Clinical symptoms were gathered using questionnaires and incorporated into a multinomial logistic prediction model to evaluate their role in diagnosing obstructive lung diseases.

Results: A total of 1443 patients were analyzed: 177 (12.3%) with COPD, 135 (9.4%) with asthma, 163 (11.3%) with ACOS, and 968 (67.1%) without obstruction. The average age was 64 years (SD 13.23), with COPD patients being older than those with asthma or ACOS. Forced expiratory volume in the first second of expiration/forced vital capacity ratios after bronchodilator use were 61.1 (SD 8.48) for COPD, 78.9 (SD 6.99) for asthma, 57.3 (SD 9.48) for ACOS, and 81.7 (SD 7.15) for non-obstructed patients. The area under the curve for diagnosing COPD was 0.75, for asthma 0.68, and for ACOS 0.78 (all PP  <  0.001).

Conclusions: Clinical variables can identify patients with obstructive lung diseases effectively, offering strong diagnostic performance and precision.