Prevalence and diagnosis of chronic respiratory symptoms in adults

To investigate the prevalence and diagnosis of chronic respiratory disease in adults.

Screening questionnaire was sent to all patients aged 40-70 on the register of a group general practice; those responding positively were sent a detailed questionnaire and invited for assessment of respiratory function by forced expiratory volume in one second, forced vital capacity, peak flow rate, and reversibility studies with a beta adrenergic inhaler.

Group general practice in south west London.

Of 2387 patients aged 40-70, 1444 completed a screening questionnaire. Of the 509 patients who reported cough, phlegm, wheeze, or shortness of breath, 324 responded to a detailed questionnaire, 256 of whom had simple respiratory function assessed. Chronic bronchitis affected 106 (17%) men and 58 (7%) women, and wheeze occurring at least once a week affected 60 (9%) men and 20 (3%) women. Only a half to a third of patients had received a diagnostic label of chronic bronchitis or asthma for their symptoms. There was considerable clinical and physiological similarity (including reversibility of the airways) between patients labelled as having asthma and having chronic bronchitis. A label of asthma was used more often for patients of social classes I and II.

Comparison with prevalence surveys carried out in the 1950s showed that respiratory symptoms are as common now as then, but the risk of disabling chronic bronchitis has fallen, more among men than women, probably because of their reduced smoking. Changes in diagnostic fashion, together with increased detection, may have contributed to the upward trend in reported morbidity from asthma over the past 30 years.