The estimated prevalence of chronic obstructive pulmonary disease in a general practice population

To estimate the prevalence of chronic obstructive pulmonary disease (COPD) in a general practice population in the UK. Four postal respiratory questionnaire surveys were carried out between 1993 and 2001. Subjects from the 2001 study were invited for spirometry if they were aged 30 years or more, had indicated that they were 'ever smokers' in any of the surveys, and/or had been considered to have likely obstructive airways disease on the basis of their replies to the 2001 questionnaire. 2646 subjects were invited for spirometry of whom 871 (32.9%) attended. Results were available for 825 participants. 163 of these subjects were categorised as having COPD. The estimated prevalence in the whole population was 4.1% with the highest prevalence (14.7%) in those aged 60-69 years. In those aged over 40 years it was 9.6%. This study suggests that the prevalence of COPD is much higher than the previous estimates of between 1 and 2%.