Exacerbation-susceptible subtype may exist in COPD
Metabolic syndrome predicts death, cardio disease
Patients who have chronic obstructive pulmonary disease (COPD) with frequent exacerbations may have a distinct phenotype in moderate and severe disease stages, researchers found.
Researchers reviewed exacerbations in 2,138 patients for three years in a large observational study, the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study. Recruitment criteria included ages 40 to 75, a history of 10 or more pack-years of smoking, forced expiratory volume in 1 second (FEV1) of less than 80% of predicted value after bronchodilator use, and FEV1 to forced vital capacity of 0.7 or less. Patients were measured at baseline, at three and six months, and every six months for three years.
Exacerbations were defined by the patients' primary doctors based on common clinical criteria, such as events that led a clinician to prescribe antibiotics and/or corticosteroids, or that led to hospitalization. Researchers applied Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages. Results appeared in the Sept. 16 New England Journal of Medicine. The study was funded by GlaxoSmithKline.
Exacerbation rates increased as GOLD stage severity did. But the single best predictor of exacerbations across all GOLD stages was an exacerbation treated in the previous year (odds ratio, 4.3; 95% CI, 3.58 to 5.17; P<0.001). Among 945 patients with moderate COPD, 208 (22%) had two or more during the first year of the study. Among the 293 patients in the study with severe COPD, 138 (47%) had two or more exacerbations during the first year of the study, and 84 (29%) had no exacerbations.
Severe COPD patients free of exacerbations one year prior to study entry were less likely to have them during the three-year study period (odds ratio, 4.53; 95% CI, 2.62 to 7.82; P<0.001). No other variables were significantly associated with exacerbations.
The study author wrote that if the exacerbation-susceptibility phenotype exists, it may represent an intrinsic susceptibility or exposure to triggers such as respiratory viral infections. Identifying this phenotype may help doctors better target patients for interventions.