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News : Using Census 2021 data to unlock diabetes prevalence estimates

IDS Icons Health

The objective

In England, latest figures show that over 3.5 million people have been diagnosed with type 2 diabetes. However, evidence supports that a significant number of people with type 2 diabetes are undiagnosed. Analysis from the Office for National Statistics (ONS) estimates that around 30% of people that have type 2 diabetes are undiagnosed. 

And key to ensuring good decision making, and the most appropriate service design and delivery by our healthcare commissioners and providers is a detailed understanding of these estimates.

Last year, a team of analysts from the Clinical Epidemiology team in the UK Office for Health Improvement and Disparities (OHID) (opens in a new tab)  set out to significantly update invaluable sub-national estimates of disease prevalence in England in 2021. 

How they did it 

The team used the Integrated Data Service (IDS) - a Trusted Research Environment that enables approved users to access a wealth of linked de-identified datasets in a safe and secure way. 

One key dataset within the IDS is the Census 2021. With the Census being the largest national survey undertaken by the ONS, it provides rich and diverse information on household demographics.

The team at OHID used record-level Census 2021 data to calculate the count of usual residents (aged 16 or over) in England. These were further arranged by: 

  • sex
  • age group
  • ethnic group
  • area deprivation 

Area deprivation was selected for the whole of England, alongside: 

  • Local authorities
  • Administrative regions
  • Integrated Care Boards (ICB)
  • sub-ICB locations
  • National Health Service (NHS) Regions 

For the first time, this enabled more robust estimates on the prevalence of diagnosed and undiagnosed type 2 diabetes (opens in a new tab)  for local areas across England. 

Previously, older data from the Census 2011, combined with less reliable administrative data sources, was used for this work.

What they found 

Since this work, the total prevalence of type 2 diabetes in England (for those aged 16 and over) in 2021 was estimated at 7.8% of the population. 

The West Midlands region had the highest estimated prevalence (8.6%) with the South East region the lowest (7.0%).  

2831 IDS Diabetes Prevalence Graphic v1 00 02
Figure 1: estimated total diagnosed and undiagnosed type 2 diabetes prevalence (and 95% confidence intervals), people aged 16 and over, England regions, 2021.

These estimates summarise the level of risk of having type 2 diabetes for the general population. You can read more about the new available diabetes data (opens in a new tab)  from the ‘Fingertips public health profiles’ on the Department for Health and Social Care website. 

How the findings will be used

Integrated Care Boards have begun to use this data to make business cases around diabetes care and to demonstrate unmet need.

Previously, prevalence estimates have been used to calculate the costs of diabetes care for the NHS, published by Diabetes UK using the economic impact of undiagnosed diabetes, and its growing prevalence. 

Further, the NHS Rightcare and NHS England can use the findings to identify areas with the largest undiagnosed prevalence and areas with the largest populations at risk of having diabetes. 

As this data is not available anywhere else, local authorities also make use of this data - helping to emphasise the importance of the NHS Health Check Programme. 

Additionally, Diabetes UK have previously used the estimates to raise awareness and advocate for improving care recover post-pandemic. You can read their article (opens in a new tab)  published in 2023. 

Next steps

The team further plans to use the population structure results to model the prevalence of type 2 diabetes for the years beyond 2021. They also hope to expand this work with other health conditions, such as non-diabetic hyperglycaemia, for local areas.