External national validation of the Leicester Self-Assessment score for Type 2 diabetes using data from the English Longitudinal Study of Ageing

AimsTo validate the Leicester Self-Assessment score using a representative English dataset for detecting prevalent non-diabetic hyperglycaemia or undiagnosed Type 2 diabetes (defined as HbA(1c) 6.0%) and for identifying those who may go on to develop Type 2 diabetes within 10 years. MethodsData were taken from the English Longitudinal Study of Ageing, a nationally representative dataset of people aged 50 years. The area under the receiver-operator curve and performance metrics for the score at the recommended score threshold (16), were calculated for the outcomes of HbA(1c) 42 mmol/mol (6.0%) at baseline and self-reported Type 2 diabetes within 10 years in those aged 50-75 years at baseline. ResultsA total of 3203 individuals had a baseline HbA(1c) measurement, of whom 247 (7.7%) had an HbA(1c) concentration 42 mmol/mol (6.0%). The area under the receiver-operator curve was 69.4% (95% CI 66.0-72.9) for baseline HbA(1c) 42 mmol/mol. A total of 3550 individuals had diabetes status recorded at 10 years, of whom 324 (9.1%) were diagnosed with Type 2 diabetes within this time; the area under the receiver-operator curve for this outcome was 74.9% (95% CI 72.4-77.5). The score threshold of 16 had a sensitivity of 89.2% (95% CI 85.3-92.4) and a specificity of 42.3% (95% CI 40.5-44.0) for Type 2 diabetes within 10 years. ConclusionsThe Leicester Self-Assessment score is validated for use across England to identify people with non-diabetic hyperglycaemia or undiagnosed Type 2 diabetes. Those with a high score are at high risk of developing diabetes in the future.