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93 Risk factors associated with potentially serious incidental findings and with serious final diagnoses on multimodal imaging in the UK biobank imaging study
  1. Lorna Gibson
  1. University of Edinburgh


Objectives Some form of clinical assessment, such as imaging, blood tests, primary or secondary care appointments and invasive procedures, is usually generated when healthy research participants receive feedback of potentially serious incidental findings (PSIFs, defined here as findings that indicate the possibility of conditions which, if confirmed, would carry a real prospect of seriously threatening life span, or of having a substantial impact on major body functions or quality of life). However, only around 1/5 PSIFs turn out to represent serious disease. Understanding the factors associated with increased risks of PSIFs and of serious final diagnoses may influence individuals’ decisions to participate in imaging research, and will inform researchers’ designs of appropriate PSIFs policies for future research studies in order to minimise the risks of overdiagnosis in healthy research volunteers.

Methods We included all UK Biobank participants who undertook an imaging assessment up to December 2015 (n=7334, median age 63 [interquartile range 56–68], 3,804 [51.9%] women). Brain, cardiac and body magnetic resonance, and dual energy x-ray absorptiometry images from the first 1000 participants were reviewed systematically by radiologists for PSIFs. Subsequently, radiographers flagged potentially concerning images for review by radiologists. We classified final diagnoses as serious or not based on survey data from participants and their GPs, and clinical correspondence collected up to six months following feedback of a PSIF. We used binomial logistic regression models to investigate associations between PSIFs protocol, age, sex, ethnicity, socio-economic deprivation, private healthcare use, alcohol intake, diet, physical activity, smoking, body mass index and morbidity with both PSIFs and serious final diagnoses.

Results Systematic radiologist review generated 13 times more PSIFs than radiographer flagging (179/1000 [17.9%] versus 104/6334 [1.6%], OR 13.3, 95% CI 10.3–17.1, p<0.001) and proportionally fewer serious final diagnoses (21/179 [11.7%] versus 33/104 [31.7%]). Older age was associated with increased odds of PSIFs and of serious final diagnoses under both protocols (sex-adjusted ORs [95% CI] for oldest [67–79 years] versus youngest [44–58 years] group for PSIFs and serious final diagnoses, respectively: 1.59 [1.07–2.38] and 2.79 [0.86–9.0] for systematic radiologist review; 1.88 [1.14–3.09] and 2.99, 95% CI [1.09–8.19] for radiographer flagging). No other investigated factor was convincingly associated with either PSIFs or serious final diagnoses.

Conclusion Systematic radiologist review generates many more PSIFs, and proportionally fewer serious final diagnoses, compared to radiographer flagging. The risks of PSIFs and serious final diagnosis are most greatly affected by PSIFs protocol, and to a lesser extent by age. Only around 1/5 PSIFs are finally diagnosed as serious disease, and appropriate PSIFs protocol design is therefore paramount to minimise the risks of overdiagnosis in healthy research participants. Direct comparison of different PSIFs protocols are essential to inform the design of PSIFs protocols for future imaging studies.

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