Abstract
Aims:
Asthma is frequently under-diagnosed with a wide variation in incidence rates. We aimed to assess how physicians in a Portuguese sentinel practice network perform using standardised diagnostic criteria.
Method:
Patients consulting one of the 43 network physicians with complaints suggestive of asthma were enrolled in the study over a four-year period. Symptom frequency and diagnoses of asthma were tabulated. Diagnostic accuracy was computed by dividing the rate of asthma diagnosis by the true rate using established diagnostic criteria.
Results:
Over four years, 43 physicians followed 32,103 patients (128,412 patient-years) and diagnosed asthma in 310. The diagnosis was confirmed in 260 cases, giving a true incidence rate of 2.02/1000/year (95% confidence interval 1.8 to 2.2) and an accuracy of diagnosis of 84%.
Conclusions:
Asthma incidence approaches published rates if accepted criteria are used. Educational efforts to ensure more accurate diagnosis may improve outcomes for asthma patients.
Keywords: asthma, incidence, diagnosis, diagnostic accuracy, family practice, general practice, Portugal
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Footnotes
Dr Correia de Sousa has received sponsorship to attend international meetings from Novartis and MSD and honoraria for lecturing and attending advisory boards from AstraZeneca and Altana. His department has received research funding from AstraZeneca. Dr Silva received sponsorship to attend local and international meetings from AstraZeneca and MSD.