Prognostic factors for COPD outcome - a nationwide cohort study

Background. Chronic Obstructive Pulmonary Disease (COPD) is a chronic disease with deterioration in lung function and increasing risk of hospitalization over time. This study aimed to investigate the impact of clinical factors on COPD exacerbations and hospitalizations. Methods: The study was a nationwide, population-based cohort study utilizing Danish health registries. 49.826 patients ≥40 years of age, with an in- and/or outpatient diagnosis of COPD (ICD-10 J44) in 2008–2017, were identified in the nationwide Danish COPD Registry. Multiple descriptive data were registered such as marital status, education, comorbidities, MRC, and smoking status. Patients were followed for 12 months and Poisson regression as well as Cox Regression was used to calculate the impact of these data on exacerbations, hospitalization and death. Exacerbations were divided into moderate and severe exacerbations. Index was the date of the first outpatient visit. Results. In all, 49.826 patients with COPD (mean age 69.2 years, 52% females) were included. COPD related exacerbations and hospitalization were associated with numbers of comorbidities, MRC and FEV1. Same results were found for hospitalization due to any diagnosis. According to survival, results were similar. Furthermore, smoking status was important for survival as never smokers had a significantly lower mortality ratio (HR 0.75, ref. former smokers) than present smokers (HR 1.2, ref. former smokers). Discussion. Smoking is the most important risk factor for COPD and smoking cessation is recommended to all COPD patients in line with physical activity and a healthy diet. This study shows a significant positive impact on smoking cessation for both exacerbations and hospitalizations.