The finding of 34% of nonsmokers among COPD patients is higher than expected, but this was probably due to misclassification of former smokers as nonsmokers. The use of anamnestic questionnaires with a very detailed series of information probably helped in addressing the clinical reasoning toward a more confident diagnosis. There is evidence in the literature that the systematic use of a simple questionnaire on smoking and symptoms of COPD is very helpful in case finding. We have no comparison data on whether evaluation of patients by GPs in a “native” setting without a standard questionnaire would have yielded a lower probability of case finding and correct diagnosis of COPD or asthma.
The main symptoms at the moment of the enrollment visit were cough in the majority of patients, followed by dyspnea, wheezing, and chest tightness. According to logistic regression analysis, the peculiar characteristics of asthmatic patients were as follows: young age, allergy, wheezing, and absence of tobacco smoking. On the contrary, smoker subjects with dyspnea, age > 65 years, history of occupational exposure, and no allergy had the highest probability to receive a diagnosis of COPD. However, GPs should be enabled to diagnose early mild or mild-to-moderate asthma or COPD, when the use of questionnaires is insensitive and the possibility of access to spirometry may be even more important than in advanced cases.
It is interesting to observe that some of the limitations emerging in our research were also reported in studies of similar or larger extension than ours on the field application (ie, outside a definite research protocol) of office spirometry conducted in other countries. In Ontario, economic incentives proved to influence the use of office spirometry increasing the number of GPs involved but not the volume of activity of each GP; notwithstanding, wide regional variations were found in spirometry utilization with a small number of GPs performing a very high number of studies without any quality and appropriateness control and, conversely, several areas with insufficient access to spirometry.