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

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. ### Competing Interest Statement KK was Chair of the NICE Public Health Guidance (PH38) Type 2 diabetes: Prevention in people at high risk. KK has acted as a consultant, speaker or received grants for investigator-initiated studies for Astra Zeneca, Bayer, Novartis, Novo Nordisk, Sanofi-Aventis, Lilly and Merck Sharp & Dohme, Boehringer Ingelheim, Oramed Pharmaceuticals, Pfizer, Roche and Applied Therapeutics. RJ is currently employed by Diabetes UK. ### Funding Statement There was no dedicated funding for this study ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The UK Statistics Authority Data Ethics Team granted ethical approval for this analysis I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data from the Health Survey for England is available for researchers to access via the UK Data Service.