Diagnostic accuracy of primary care asthma/COPD working hypotheses, a real life study

Misdiagnoses are inevitable when working hypotheses of asthma/COPD of General Practitioners (GPs) are not checked by spirometry. To reduce misdiagnoses, Asthma/COPD-support services (AC-services) offer support by performing spirometry assessed together with written medical history by consulting pulmonologists.

Which criteria do GPs use to justify their asthma/COPD working hypotheses? How do diagnostic assessments by an AC-service change GPs' working hypotheses? Do GPs' justifications for their working hypotheses influence the extent to which working hypotheses correspond with diagnoses given by an AC-service?

We investigated the working hypotheses of 17 GPs for 284 patients with respiratory problems and their justifications: "clinical symptoms", "office spirometry", or "specialist's correspondence". Working hypotheses were compared with diagnoses given by an AC-service, and the influence of the different justifications categories on diagnostic accuracy of the working hypotheses was described.

49% of the working hypothesis were only based on clinical information, 21% were also based on office spirometry. For 30% additional specialist information was available. 50% of the working hypotheses were confirmed by the AC-service. The working hypothesis asthma was confirmed more frequently (62%) than the working hypothesis COPD (40%). The justifications for the working hypotheses given by GPs did not influence these results.

Diagnostic assessments of the AC-service differed significantly from the working hypotheses of GPs, even when these were based on previous specialists' correspondence or on office spirometry. To optimize the diagnoses in primary care, diagnostic support of an AC-service is recommended for all primary care patients with respiratory problems.