Objectives: To estimate the prevalence of undiagnosed chronic obstructive pulmonary disease (COPD) in a population of general practice patients at risk for developing COPD. A further aim was to evaluate the presence of respiratory symptoms as a predictor for the diagnosis of COPD.
Methods: This study was conducted by eight general practitioners (GP) in six semi-rural general practices. During two consecutive months all patients attending their GP were included if they met the following criteria: current smokers between 40 and 70 yr of age, and a smoking history of at least 15 pack-years. A questionnaire regarding smoking history, respiratory symptoms, exposure to dust or chemical fumes, and history of respiratory diseases was completed for all patients. Subjects without known COPD were invited for spirometric testing.
Results: Off the 146 general practice patients included, 17.1% already had an established COPD diagnosis. Screening by spirometry revealed a 46.6% prevalence of COPD. Underdiagnosis of COPD was more frequent in the younger age categories (40-49 Yr; 50-59 Yr). Objective wheezing was the only sign that was significantly more frequent in COPD patients than in non-COPD patients (P<0.001). Patients with previously known COPD were significantly older, and complained more of chronic cough and fatigue than newly detected patients.
Conclusion: Almost half of a general practice population of current smokers between 40 and 70 years of age, with a smoking history of at least 15 pack-years, was diagnosed with COPD, and roughly two thirds of these were newly detected as a result of the case finding programme.