Socioeconomic status and prognosis of COPD in Denmark

We investigated the association between length of school education and 5-year prognosis of chronic obstructive lung disease (COPD), including exacerbations, hospital admissions and survival. We used sample of general population from two independent population studies: The Copenhagen City Heart Study and Copenhagen General Population Study. A total of 6,590 individuals from general population of Copenhagen with COPD defined by the Global initiative for obstructive lung disease criteria were subdivided into 4 groups based on the length of school education: 1,590 with education < 8 years; 3,131 with education 8-10 years, 1,244 with more than 10 years, but no college/university education and 625 with college/university education. Compared with long education, short education was associated with current smoking (p < 0.001), higher prevalence of respiratory symptoms (p < 0.001) and lower forced expiratory volume in the first second in percent of predicted value (FEV1%pred) (p < 0.001). Adjusting for sex, age, FEV1%pred, dyspnea, frequency of previous exacerbations and smoking we observed that shortest school education (in comparison with university education), was associated with a higher risk of COPD exacerbations (hazards ratio 1.65, 95% CI 1.15-2.37) and higher risk of all-cause mortality (hazards ratio 1.96, 95% CI 1.28-2.99). We conclude that even in an economically well-developed country with a health care system (which is largely free of charge), low socioeconomic status, assessed as the length of school education, is associated with a poorer clinical prognosis of COPD.