Impact of COVID-19 on diagnoses, monitoring and mortality in people with type 2 diabetes: a UK-wide cohort study involving 14 million people in primary care

AIMS To compare trends in diagnoses, monitoring and mortality in patients with type 2 diabetes, before and after the first COVID-19 peak. METHODS We constructed a cohort of 25 million patients using electronic health records from 1831 UK general practices registered with the Clinical Practice Research Datalink (CPRD), including 14 million patients followed between March and December 2020. We compared trends using regression models and 10-year historical data. We extrapolated the number of missed/delayed diagnoses using UK Office for National Statistics data. RESULTS In England, rates of new type 2 diabetes diagnoses were reduced by 70% (95% CI 68%-71%) in April 2020, with similar reductions in Northern Ireland, Scotland and Wales. Between March and December, we estimate that there were approximately 60,000 missed/delayed diagnoses across the UK. In April, rates of HbA1c testing were greatly reduced in England (reduction: 77% (95% CI 76%-78%)) with more marked reductions in the other UK nations (83% (83-84%)). Reduced rates of diagnosing and monitoring were particularly evident in older people, in males, and in those from deprived areas. In April, the mortality rate in England was more than 2-fold higher (112%) compared to prior trends, but was only 65% higher in Northern Ireland, Scotland and Wales. CONCLUSIONS As engagement increases, healthcare services will need to manage the backlog and anticipate greater deterioration of glucose control due to delayed diagnoses and reduced monitoring in those with pre-existing diabetes. Older people, men, and those from deprived backgrounds will be groups to target for early intervention. What is already known about this subject? What is the key question? What are the new findings? How might this impact on clinical practice in the foreseeable future? ### Competing Interest Statement All authors have completed the Unified Competing Interest form (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years. DMA reports research funding from AbbVie, Almirall, Celgene, Eli Lilly, Novartis, Janssen, UCB and the Leo Foundation outside the submitted work. MKR has received consulting fees and non-promotional lecture fees from Novo Nordisk in relation to cardiovascular disease and diabetes. The company has had no role in influencing the proposed study and is not expected to benefit from this work. Outside the submitted work, MKR reports receiving research funding from Novo Nordisk, consultancy fees from Novo Nordisk and Roche Diabetes Care, and modest owning of shares in GlaxoSmithKline. NM reports honorarium for presentations from Napp Pharmaceuticals, Novo Nordisk, Sanofi, MyLan, Boehringer Ingelheim, Lilly Diabetes, Abbott, Omnia-Med, Takeda UK and AstraZeneca. All other authors declare no competing interests. There are no other relationships or activities that could appear to have influenced the submitted work. ### Funding Statement This work was funded by the National Institute for Health Research (NIHR) Greater Manchester Patient Safety Translational Research Centre. The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. The funders of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the report. ### 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: This study is based on data from the Clinical Practice Research Datalink obtained under license from the UK Medicines and Healthcare products Regulatory Agency. The study and use of CPRD data was approved by the Independent Scientific Advisory Committee for Clinical Practice Research Datalink research (protocol number: 20_182R). All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. 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 and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The clinical codes used in this study are published on ClinicalCodes.org. Electronic health records are, by definition, considered "sensitive" data in the UK by the Data Protection Act and cannot be shared via public deposition because of information governance restriction in place to protect patient confidentiality. Access to data are available only once approval has been obtained through the individual constituent entities controlling access to the data. The primary care data can be requested via application to the Clinical Practice Research Datalink.