The analysis of national scale patient data has been central to pandemic responses both in the UK and internationally, as we monitor, learn, and provide evidence to help mitigate the effects of COVID-19 in near real-time.

The advances made during these extraordinary circumstances also present major opportunities to drive forward innovation and data-informed improvements in healthcare, and outcomes for many other conditions.

In health settings with established electronic health record infrastructures, health data collected in the real world as part of routine service provision offer a hugely valuable resource to improve our understanding of diseases and treatments. Data are continuously updated, cover long periods of time, and can provide a population-wide perspective.

These large-scale data provide the opportunity to explore patterns in specific groups, such as people with particular medical conditions, ethnic minorities, age groups, sex, affluence, and other characteristics. They can be used to complement clinical trials, including information from those who would not be eligible to take part, and allow the ability to monitor trends and changes in near real-time.

Routinely collected health data are particularly useful when multiple datasets can be linked together to follow the patient journey.

EAVE II – a national scale dataset

Set up in the early stages of the COVID-19 pandemic, EAVE II (Early Pandemic Evaluation and Enhanced Surveillance of COVID-19) is a pioneering study using de-identified patient data to track COVID-19 across Scotland.

Our study is a collaboration across Scottish universities, led by the University of Edinburgh in conjunction with Public Health Scotland, and supported by BREATHE – The Health Data Research Hub for Respiratory Health.

Together, we set up one of the first national-scale datasets in the world, covering 5.4 million individuals, or 99% of the Scottish population. Health data from different sources are securely linked together by experts creating an important end-to-end resource, including information from GP consultations, prescriptions, vaccination, out-of-hours consultations, use of accident and emergency, hospital admissions, intensive care unit admissions, deaths, and results from COVID-19 tests.

This has allowed our trained, approved researchers to understand more about the COVID-19 pandemic across the whole population, in near real-time.

The EAVE II study has been transformative for national and international health, social, and economic planning during the pandemic. Using detailed, nationwide analysis we can explore answers to questions being asked by the public and governments and enable policymakers to make crucial decisions based on the latest health data.

In early 2021, we were the first to report on the real-world impact of the COVID-19 vaccination programme at a national level, with data across Scotland indicating a substantial reduction in the risk of hospital admissions following a first dose of the Oxford-AstraZeneca or Pfizer-BioNTech vaccines.

By being able to focus on different age groups, our team found that hospital admissions were reduced by 83% in those aged 80 and over. This was particularly important because elderly people were under-represented in the original vaccine trials and hence, there was uncertainty if vaccines would be effective in this age group. Estimates of this kind would not have been possible without the national scale of the dataset.

Several international countries – including France, Canada, and Germany – altered their policy positions following publication of EAVE II findings, such as making the Oxford-AstraZeneca vaccine available to older people.

Alongside broader population-level policy decisions, findings on this scale also have the potential to deliver impact at a more individual level.

A recent study using the EAVE II dataset found that children with poorly controlled asthma are three to six times more likely to be hospitalised with COVID-19 than those without the condition.

Our findings indicate that children with poorly controlled asthma are particularly likely to benefit from COVID-19 vaccination and provide further evidence of the importance of getting asthma under control in children, through measures such as supported self-management.

None of these insights – which have been crucial to supporting the COVID-19 pandemic response – would have been possible without population-level patient data. When de-identified data from many individuals are brought together, it helps us to see the big picture – every patient provides a piece of the puzzle.

Public trust is paramount to this type of research. The public must have confidence that their privacy is robustly protected with appropriate restrictions and safeguards, and data are only used where there is a clear public benefit.

The goal of our research is to harness population health data to ultimately deliver benefits back to patients. It is therefore important to ensure our research directly addresses patient needs.

In partnership with charities, including the Asthma UK and British Lung Foundation Partnership and Cystic Fibrosis Trust, a recent research prioritisation exercise involving people with underlying lung diseases has led to the launch of a new UK-wide study, supported by BREATHE and the Asthma UK Centre for Applied Research.

Announced by Health Data Research UK and the Alan Turing Institute, the research project will use national data to find out if those with chronic lung diseases are at a higher risk of cardiovascular complications after having COVID-19 than people who do not have lung diseases. The study will help better understand complications following COVID-19 in people with lung disease; if we should be treating them differently or even if some treatments are taken for lung disease protect from some COVID-19 complications.

The COVID-19 pandemic has catalysed a new era for population health. We have witnessed pioneering research inform life-saving decisions across the globe, with significant scope for similar techniques to be used for other diseases.

Health systems are typically flying blind without access to the data they need or working from information that is out of date. National scale data could provide decision-makers with more real-time information to help combat diseases like cancer, diabetes, cardiovascular disease, and respiratory disease in the UK and across the world.

Cross-institution and cross-sector collaborations, such as BREATHE and the Asthma UK Centre for Applied Research, have an important role to play in achieving this vision. Working together, we are driving ground-breaking research and innovation for respiratory health, with the support and tools needed to realise the full potential of health data.

As attention begins to shift from an urgent COVID-19 pandemic response to day-to-day management, it is imperative that we keep these open flows of data and not close the door on the opportunity to translate the huge strides in research we have seen in COVID-19 to other conditions. The potential benefits for the future of health and care are enormous.

Professor Aziz Sheikh, OBE is the Director of the Usher Institute at The University of Edinburgh as well as Study Lead of EAVE II. He is also Director of BREATHE – The Health Data Research Hub for Respiratory Health and Director of Asthma UK Centre for Applied Research.

This article was published in issue 20 of Health Europa Quarterly.