COPD prevalence is underestimated

Epidemiologic studies examining the incidence of respiratory symptoms show that COPD is a major health problem in Europe. They also indicate that COPD is often under-diagnosed, so that the true prevalence rates and the burden of disease may be much higher than the currently available data suggest (Pauwels, 2000; Wouters, 2003; Halbert et al., 2003).

Estimates of COPD prevalence rates vary widely, from 0.2% to 18.3%, partly as a result of real differences in prevalence among countries and regions, and partly because of other factors. These factors include the method by which the prevalence is estimated (expert opinion, patient-reported diagnosis, symptom-based or spirometry-based), the definition of COPD that was used, age and smoking status of the population included, etc. Some well-designed studies have found a measured prevalence of COPD in Europe between 4% and 10% of adults (Halbert et al., 2003).

Spirometry-based estimates of COPD prevalence in selected EU countries are taken from a study (Halbert et al., 2003) that has recently summarised the available prevalence data on the world scale. Only 32 sources in 17 countries could be identified, that estimated COPD prevalences for a population and clearly described the methods that were used. Poor comparability of the COPD prevalence data hinders meaningful comparisons among EU countries.

Factors determining COPD prevalence

The COPD prevalence increases with age. Since COPD is a low-progressive disease, it is easier to find it in elderly people. The rapid decline of pulmonary function, which is typical of COPD, can be associated with the physiological decline of the function itself.

Lower socio-economic status, independent of smoking behaviour, negatively affects the pulmonary function and thus also the susceptibility to, and the severity of COPD (Pauwels, 2000).

Men have a higher prevalence than women, due to the greater smoking exposure. Among non-smokers women have a higher presence of COPD than men. Research suggests that about 85% of aged never-smokers with COPD are women (Massaro & Massaro, 2004).

Trends in COPD prevalence

Smoking is the primary risk factor for developing COPD, and the COPD prevalence trends generally follow the tobacco smoking behaviour in the population. However, some countries record a low COPD prevalence in spite of high rates of smoking. Data obtained by objective measurements (spirometry) suggest that prevalence underestimates are responsible for this discrepancy (Halbert et al., 2003).

With smoking prevalence rates still increasing among European women, it is likely that COPD will in particular affect that segment of population in the near future.

The expected ageing of the EU population will further contribute to the burden of COPD in the coming decades.

More comparable data are required to assess the extent of COPD morbidity and its future trends in the EU.