P.R.S. Tirimanna

Underdiagnosis of asthma: is the doctor or the patient to blame? The DIMCA project

BACKGROUND It is important to diagnose asthma at an early stage as early treatment may improve the prognosis in the long term. However, many patients do not present at an early stage of the condition so the physician may have difficulty with the diagnosis. A study was therefore undertaken to compare the proportion of patients who underpresented their respiratory symptoms with the proportion of underdiagnosed cases of asthma by the general practitioner (GP). A secondary aim was to investigate whether bad perception of dyspnoea by the patient was a determining factor in the underpresentation of asthma symptoms to the GP. METHODS A random sample of 1155 adult subjects from the general population in the eastern part of the Netherlands was screened for respiratory symptoms and lung function and the results were compared with the numbers of asthma related consultations registered in the medical files of the GP. In subjects with reduced lung function the ability to perceive dyspnoea was investigated during a histamine provocation test in subjects who did and did not report their symptoms to their GP. RESULTS Of the random sample of 1155 subjects 86 (7%) had objective airflow obstruction (forced expiratory volume in one second (FEV1) below the reference value corrected for age, length, and sex minus 1.64SD on two occasions) and had symptoms suggestive of asthma. Of these 86 subjects only 29 (34%) consulted the GP, which indicates underpresentation by 66% of patients. Of all subjects with objective airflow obstruction who presented to their GP with respiratory symptoms, 23 (79%) were recorded in the medical files as having asthma, indicating underdiagnosis by the GP in 21% of cases. Of the subjects with objective airflow obstruction who visited the GP with respiratory symptoms 6% had bad perception of dyspnoea compared with 26% of those who did not present to the GP in spite of airflow obstruction (χ2 = 3.02, p = 0.08). CONCLUSIONS Underpresentation to GPs of respiratory symptoms by asthmatic patients contributes significantly to the problem of underdiagnosis of asthma. Underdiagnosis by the GP seems to play a smaller role. Furthermore, there are indications that underpresentation of symptoms by the patient is at least partly explained by a worse perception of dyspnoea.

Association between health-related quality of life and consultation for respiratory symptoms: results from the DIMCA programme

In general practice, diagnosis of chronic obstructive pulmonary disease (COPD) is hampered by underpresentation. A substantial proportion of subjects experiencing respiratory complaints do not consult their general practitioner (GP). In this study, the relationship between disease-specific quality of life and presentation of respiratory symptoms to a GP is investigated. A random sample from the general population (undiagnosed subjects) was screened for symptoms and objective signs of COPD (n=1,155). The lung function of subjects with symptoms of COPD was monitored for 6 months. During this period, 48 new COPD patients with a persistently reduced lung function (forced expiratory volume in one second (FEV1) less than or equal to the predicted value minus 2 SD) were detected. A disease-specific quality-of-life questionnaire (chronic respiratory questionnaire (CRQ)) was administered and clinical and GP consultation data were collected. Multivariate analysis showed that quality-of-life impairments due to dyspnoea and fatigue and variability in lung function (bronchial hyperresponsiveness, reversibility and peak expiratory flow rate variability) were related to medical consultation. Only 31% of the newly detected patients reported that they had ever visited their GP for respiratory complaints. A similarly low percentage was found in the rest of the sample (26%). It is concluded that the mere presence of respiratory symptoms or a (gradually) reduced lung function is insufficient reason for patients to seek medical help. Subjects are more likely to consult their general practitioner once their quality of everyday life is affected or they experience variability in lung function.