Sociodemographic and health-related differences in non-diabetic hyperglycaemia and undiagnosed type 2 diabetes in the Health Survey for England 2013-2019

Abstract Background Type 2 diabetes is a leading cause of morbidity and mortality but is often undiagnosed. Non-diabetic hyperglycaemia increases T2D risk, and its prevalence is increasing. Understanding the scale of undiagnosed T2D and NDH and identifying at-risk groups is important for detection and intervention. Methods We used the 2013-2019 Health Survey for England, an annual, nationally representative, cross-sectional survey. Respondents aged 16 + who were not pregnant and had valid HbA1c measurements were included. Outcomes were undiagnosed T2D (HbA1c ≥48 mmol/mol (6·5%) and no T2D diagnosis), and NDH (HbA1c 42-47 mmol/mol (6·0-6·4%) and no diagnosis). Age-adjusted prevalence was estimated across sociodemographic and health-related characteristics. Independent associations were assessed using logistic regression. Findings An estimated 2·25% (95% confidence interval 2·05-2·45) of adults had undiagnosed T2D and 11·54% (11·11-11·97) had NDH; an estimated 999,700 and 5,121,800 adults respectively. Prevalence was higher in those with known risk factors for T2D, such as older age or Black or Asian ethnicity. Among those with T2D, 30·21% (28·13-32·28) were undiagnosed. Younger adults and those self-reporting better health were most likely to be undiagnosed. For women, lower BMI, and waist circumference, not being prescribed antidepressants, and living in rural areas, were associated with increased likelihood of being undiagnosed. Interpretation Nearly a third of T2D cases were undiagnosed. Some groups less likely to have T2D were most likely to be undiagnosed. NDH is prevalent across all groups, even those considered low risk. Findings highlight the burden of T2D and NDH and emphasise the need for awareness across the population.