Defining high probability when making a diagnosis of asthma in primary care: mixed-methods consensus workshop. Issue 4 (20th April 2020)

• Record Type: Journal Article
• Authors: Daines, Luke; Lewis, Steff; Schneider, Antonius; Sheikh, Aziz; Pinnock, Hilary
• Is Part Of: BMJ open. Volume 10:Issue 4(2020)
• Publication Date: 2020-04-20
• Subjects: asthma -- primary care -- qualitative research; Medicine -- Research -- Periodicals; 610.72
• DOI: 10.1136/bmjopen-2019-034559
• Languages: English
• ISSNs: 2044-6055

Abstract

Abstract : Objective: Making the diagnosis of asthma is challenging. Guidelines recommend that clinicians identify a group at 'high probability' of asthma. High probability, however, is not numerically defined giving rise to uncertainty. The aim of this work was to build consensus on what constitutes a high probability of asthma in primary care. High probability was defined as the probability threshold at which there is enough information to make a firm diagnosis of asthma, and a subsequent negative test would not alter that opinion (assumed to be a false negative). Design: Mixed-methods study. Setting: A consensus workshop using modified nominal group technique was held during an international respiratory conference. Participants: International conference attendees eligible if they had knowledge/experience of working in primary care, respiratory medicine and spoke English. Methods: Participants took part in facilitated discussions and voted over three rounds on what constituted a high probability of asthma diagnosis. The workshop was audio-recorded, transcribed and qualitatively analysed. Results: Based on final votes, the mean value for a high probability of asthma in primary care was 75% (SD 7.6), representing a perceived trade-off between limiting the number of false positives (more likely if a lower threshold was used) and pragmatism on the basis that first-line preventive therapies (ie, low-dose inhaled corticosteroids) are relatively low risk. The need to review response to treatment was strongly emphasised for detecting non-responders and reviewing the diagnosis. Conclusion: A consensus probability of 75% was the threshold at which the primary care participants in this workshop felt confident to establish the diagnosis of asthma, albeit with the caveat that a review of treatment response was essential. Contextual factors, including availability and timing of tests and the ease with which patients could be reviewed, influenced participants' decision making.