Prevalence and clinical characteristics of persistent airflow limitation in a cohort of adults with asthma and/or chronic obstructive pulmonary disease

Rationale: The clinical characteristics of persistent airflow limitation (PAL) were explored in patients aged ≥12 years with physician-assigned diagnoses of asthma, asthma plus chronic obstructive pulmonary disease (COPD), or COPD in the NOVEL Observational longiTudinal studY (NOVELTY) cohort. The NOVELTY study is a prospective study conducted in primary and secondary care in 18 countries. Objectives: To determine the proportion of patients with PAL at baseline, their baseline characteristics, and the stability and prognostic utility of PAL during follow-up. Methods: PAL was defined as post-bronchodilator forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) ratio less than the lower limit of the normal range (European Respiratory Society [ERS]/American Thoracic Society [ATS]) or as <0.7 (Global Initiative for Chronic Obstructive Lung Disease [GOLD] criteria). Results: We studied 9081 patients over 3 years (asthma: 4754; asthma + COPD; 1147; COPD: 3180). Baseline prevalence of PAL was 24.2% and 29.2% (asthma), 63.3% and 74.1% (asthma + COPD), and 65.4% and 75.8% (COPD) using ERS/ATS and GOLD criteria, respectively. Patients with PAL had markedly worse symptom burden and a history of more frequent moderate and severe exacerbations. In patients with asthma, PAL was associated with higher blood eosinophils and fractional exhaled nitric oxide (FeNO) values; 60% had never smoked. Of patients with PAL at baseline 84% continued to meet PAL criteria at Year 3. Irrespective of physician diagnosis, PAL was a marker of increased risk of moderate and severe exacerbations and poor symptom control during the 3-year follow-up. Conclusions: PAL is a stable trait associated with more severe disease and poor outcomes in adults with a physician-assigned diagnosis of asthma and/or COPD.