The Global Initiative for Chronic Obstructive Lung Disease (GOLD) guideline removed stage 0 (chronic cough and sputum without airflow obstruction, GOLD-0) because of poor prognostic value. Preventative intervention may be relevant for those with chronic symptoms; therefore, we assessed the stability, morbidity, and FEV1 decline associated with GOLD stage 0 in a representative adult population cohort.
Baseline (n = 4,060) and follow-up (n = 3,206, mean 3.5 years) clinic assessment of the North West Adelaide Health Study included postbronchodilator spirometry, anthropometry, and measures of doctor-diagnosed asthma, respiratory symptoms, smoking status, quality of life, and depression.
Baseline GOLD-0 prevalence was 17.0% (n = 584). At follow-up (n = 420), 39.8% remained stable, 1.4% progressed to GOLD stages 1 to 2, and 58.8% resolved to no symptoms. Persistent GOLD-0 at follow-up was associated with persistent smoking (men: odds ratio [OR] = 11.9, 95% CI, 6.4-22.1; women: OR = 4.0, 95% CI, 2.1-7.4), and depressive symptoms (men: OR = 3.8, 95% CI, 1.9-7.6; women: OR = 3.2, 95% CI, 1.7-5.9), with highest quartile of FEV1 decline (mL) per year (OR = 2.1, 95% CI, 1.2-3.7) and the metabolic syndrome (OR = 1.7, 95% CI, 1.01-3.0) in men, and with older age in women. These associations generally held in smokers and never-smokers. Resolving GOLD-0 was associated with smoking cessation (OR = 13.7; 95% CI, 4.6-40.1), FEV1 decline (mL) per year below the median (OR = 2.0; 95% CI, 1.1-3.5), normal BMI, and younger age groups. Sensitivity analyses based on the presence of sputum did not change the observed associations.
Persistent GOLD-0 identified people with physical and psychologic morbidity in both smokers and nonsmokers. Identification of those with persistent respiratory symptoms is therefore important. Excess FEV1 decline in men suggests GOLD-0 may identify a group at risk to progress to COPD over time.