Patient Factors and Clinical Efficacy of Early Identification and Treatment of COPD and Asthma

The Undiagnosed COPD and Asthma Population trial showed that early diagnosis and treatment of asthma and COPD by pulmonologists improved healthcare utilization, respiratory symptoms, and quality of life. To determine if the benefits of early diagnosis and treatment were greater in individuals with more advanced disease, or in individuals with asthma as opposed to COPD. We also assessed whether pulmonologist-directed care benefited asthma and COPD subgroups equally. Case finding was used to identify undiagnosed adults with chronic respiratory symptoms in the community. Five hundred and eight newly diagnosed participants with COPD or asthma were randomized to a pulmonologist-care intervention or usual care. Low and high disease-burden categories for St. Georges Respiratory Questionnaire (SGRQ) and COPD Assessment Test (CAT) were defined using a median-split of baseline scores, and MCID thresholds were used to define significant responses. Benefits of pulmonologist care were assessed by evaluating treatment effects within subgroups and by assessing treatment-by-subgroup interactions. Patients with higher disease burden at diagnosis were more likely to benefit from early diagnosis and treatment compared to those with lower disease-burden. 71% of those with high disease-burden improved their CAT by ≥ 2 points over 12 months compared to 47% with low disease burden; OR 2.78, 95% CI: 1.90 to 4.07, p<0.001. Similar results were seen for SGRQ and FEV1 improvements. In contrast, responses to early diagnosis and treatment were similar for those with asthma vs COPD. Individuals with asthma randomized to pulmonologist-directed care showed greater one-year improvements in CAT, SGRQ, SF36 and FEV1 compared to individuals randomized to primary care. However, individuals with COPD experienced similar improvements regardless of whether their treatment was managed by a pulmonologist or primary care provider. Treatment-by-disease interaction terms were not statistically significant. Patients with greater disease burden who exhibited more advanced and symptomatic asthma and COPD at the time of diagnosis, benefited more from earlier diagnosis and treatment. Patients with asthma tended to derive greater benefit from pulmonologist-directed care than patients with COPD.