Diagnostic Criteria and Treatment Approaches for Obstructive and Restrictive Lung Diseases

Spirometric Differentiation

Obstructive lung disease is defined by a post-bronchodilator FEV1/FVC ratio <0.7, while restrictive disease shows reduced FVC and FEV1 with a normal or elevated FEV1/FVC ratio, confirmed by reduced total lung capacity (TLC) 1
FEV1/FVC <0.7 post-bronchodilator is the diagnostic threshold for airflow obstruction, as recommended by the European Respiratory Society 2, 1
Pre-bronchodilator spirometry should be used initially to rule out COPD, with post-bronchodilator measurements required to confirm diagnosis, according to the American Thoracic Society 1
Post-bronchodilator testing uses 400 mcg salbutamol or 80 mcg ipratropium bromide, as stated by the European Respiratory Society 3
FEV1 percentage predicted determines severity: Mild (≥80%), Moderate (50-79%), Severe (30-49%), Very Severe (<30%), as classified by the Global Initiative for Chronic Obstructive Lung Disease 1

Long-acting bronchodilators (LAMA or LABA) are first-line therapy for symptomatic COPD patients, with short-acting bronchodilators reserved for rescue use, as recommended by the American College of Chest Physicians 1, 4, 5
Long-acting anticholinergics or long-acting β2-agonists reduce exacerbations by 13-25% compared to placebo, according to the American College of Physicians 6
Combination inhaled corticosteroids plus long-acting β2-agonists reduce mortality compared to placebo (RR 0.82, 95% CI 0.69-0.98) and inhaled corticosteroids alone (RR 0.79, 95% CI 0.67-0.94), as reported by the American Thoracic Society 6
Add inhaled corticosteroids for patients with repeated exacerbations and FEV1 <50% predicted, as recommended by the Global Initiative for Chronic Obstructive Lung Disease 4, 5

Pulmonary rehabilitation improves health status and dyspnea in symptomatic patients with FEV1 <60% predicted, as stated by the American College of Chest Physicians 4, 5, 6
Supplemental oxygen reduces mortality (RR 0.61, 95% CI 0.46-0.82) in symptomatic patients with resting hypoxia, according to the American Thoracic Society 4, 6

Screening spirometry in asymptomatic adults has no net benefit and is not recommended, as stated by the American Academy of Family Physicians 8
Post-bronchodilator results near the 0.7 threshold should be repeated to ensure diagnostic accuracy, as recommended by the American College of Chest Physicians 1