On the crest of a wave: Danish prevalence of hospitalisation-required COPD 2002-2009

Symptoms, mortality, and costs of chronic obstructive pulmonary disease (COPD) concentrate among patients who have been hospitalised with the disease. Nevertheless, no solid estimates exist of trends in the prevalence of this condition. This study aimed to investigate age- and sex-specific trends in the prevalence of hospitalisation-required COPD.

Using national registers, a cohort trend study was conducted covering the entire Danish population (5.4 million citizens) from 1994 to 2009. Subjects were classified as prevalent in the period between first COPD hospitalisation and either death, migration, or the end of an individual 8-year period with no COPD hospitalisations.

In 2009 in Denmark the prevalence of hospitalisation-required COPD was: For males 45-59 years 0.36%, 60-74 years 1.37%, 75-84 years 4.13%, 85+ years 4.33%, and for females: 45-59 years: 0.49%, 60-74 years: 1.74%, 75-84 years: 3.96%, 85+ years: 2.99%. During the period from 2002 to 2009 the overall prevalence remained constant. However, among subjects aged above and below 75 years, respectively, substantial decreases and increases were found. An increasing female prevalence exceeded male prevalence, which decreased.

Some 4% of the Danish population aged above 75 years have been hospitalised with COPD. During the period from 2002 to 2009 the overall prevalence of hospitalisation-required COPD remained constant. However, significant age-specific trends indicate that within a few years, ageing of birth cohorts with low COPD prevalence will lead to a substantial decrease in the prevalence of hospitalisation-required COPD.