COPD in the general population: prevalence, incidence and survival

Worldwide, COPD is a leading cause of chronic morbidity and mortality. Although its prevalence is already well documented, very few studies have measured its incidence. We therefore investigated the prevalence, incidence and lifetime risk of COPD in the general population. In a population-based study including subjects ≥ 40, with 12 months of history available in the Dutch IPCI database, we identified COPD cases by a two-step validation algorithm. Among 185,325 participants with 601,283 years of follow-up, 7308 subjects with COPD were identified, and 1713 had incident COPD. The overall IR of physician-diagnosed COPD was 2.92/1000PY (95%CI 2.78-3.06). The incidence of COPD was higher in men (3.54; 95%CI 3.33-3.77) than in women (2.34; 95%CI 2.17-2.52), and the overall baseline prevalence of COPD was 3.02% (95%CI 2.94-3.10). For people who had entered the study free of COPD at the age of 40, the risk of developing COPD within the next 40 years was 12.7% for men and 8.3% for women. In patients with very severe COPD, 26% died after 1 year of follow-up, whereas 2.8% died among the non-COPD subjects. In the general population in the Netherlands, three on 1000 subjects were diagnosed with COPD per year. The incidence increased rapidly with age and was higher in men than in women. One in eight men and one in 12 women, being COPD free at the age of 40, will develop COPD during their further life. Mortality rates differed substantially between COPD patients and non-COPD subjects of the same age, underlining the burden of this disease.