Survey of public definitions of the term 'overdiagnosis' in the UK

Objectives: To determine how 'overdiagnosis' is currently conceptualised among adults in the UK in light of previous research, which has found that the term is difficult for the public to understand and awareness is low. This study aimed to add to current debates on healthcare in which overdiagnosis is a prominent issue. Design: An observational, web-based survey was administered by a survey company. Setting: Participants completed the survey at a time and location of their choosing. Participants: 390 consenting UK adults aged 50-70 years. Quota sampling was used to achieve approximately equal numbers in three categories of education and equal numbers of men and women. Primary outcome measures: Participants were asked whether they had seen or heard the term 'overdiagnosis'. If they had, they were then invited to explain in a free-text field what they understood it to mean. If they had not previously encountered it, they were invited to say what they thought it meant. Responses were coded and interpreted using content analysis and descriptive statistics. Results: Data from 390 participants were analysed. Almost a third (30.0%) of participants reported having previously encountered the term. However, their responses often indicated that they had no knowledge of its meaning. The most prevalent theme consisted of responses related to the diagnosis itself. Subthemes indicated common misconceptions, including an 'overly negative or complicated diagnosis', 'falsepositive diagnosis' or 'misdiagnosis'. Other recurring themes consisted of responses related to testing (ie, 'too many tests'), treatment (eg, 'overtreatment') and patient psychology (eg, 'overthinking'). Responses categorised as consistent with 'overdiagnosis' (defined as detection of a disease that would not cause symptoms or death) were notably rare (n=10; 2.6%). Conclusions: Consistent with previous research, public awareness of 'overdiagnosis' in the UK is low and its meaning is often misunderstood or misinterpreted.