Published: 06 February 2020
The NHS collects billions of data points from patients each year, but using this routinely collected data in health research is a challenge. Jamil Mayet, Amit Kaura, Ben Glampson and Dimitri Papadimitriou outline how the NIHR Health Informatics Collaborative is making such data available and the collaboration’s first big research success in heart attacks.
Every year there are more than 17 million hospital admissions in England, according to NHS Digital Hospital Episode Statistics (HES). Every time a person is admitted to hospital, the NHS collects a range of health data, from their age to what condition they’ve been admitted for to what tests they’ve received.
This wealth of data is largely used to make sure that patients receive the best care. But what if this unique data, collected from every hospital in the country, was available for health research?
From a challenge to a collaborative
In 2014 Dame Sally Davies, former Chief Medical Officer, set this exact challenge to the five NHS Trusts in England with the largest NIHR Biomedical Research Centres (BRCs). The NIHR Health Informatics Collaborative (HIC) was formed to demonstrate how sharing of NHS clinical information, held electronically, could facilitate more effective clinical research, and lead to benefits for patients and the public, researchers and NHS staff.
The HIC was initially made up of five BRCs and their respective NHS Trusts and university partners – Oxford University Hospitals NHS Foundation Trust, Imperial College Healthcare NHS Trust, Guy's and St Thomas' NHS Foundation Trust/Kings College Hospital NHS Foundation Trust, Cambridge University Hospitals NHS Foundation Trust and University College London Hospitals NHS Foundation Trust. Since then the collaborative has expanded to include 23 NHS Trusts from across England.
Using routinely collected NHS data
The aim of the HIC is to improve the availability and quality of routinely captured hospital data and to make it available for multi-site translational research. The collaborative then uses this data in an anonymised form to answer pressing clinical and research questions, helping us understand the complex care delivered in the NHS and how care can be improved to provide the best services to patients.
Collecting data directly from electronic patient record systems drastically reduces the time and cost for data collection for research, and allows for the creation of much larger datasets compared to traditional research projects, which rely on recruiting patients individually.
The use of routinely captured data does however also bring its own challenges. The fact that each participating NHS site has its own electronic patient record system means that data are captured differently at each trust; this can make the process of compiling all sites’ data into one dataset challenging. Additionally, not all data are collected electronically at each site, and large amounts of crucial electronic data are often recorded in free text rather than in a structured format.
The HIC overcomes these issues by creating data warehouses at each site that read in and transform data to standardised structures and formats, validating and cataloguing data so that it is clear what the data was captured for and how it should be used. The collaborative also has projects running that aim to extract structured data from free text and share methods and codes across the NHS to reduce duplication of methods.
Collating data on acute coronary syndrome
Acute coronary syndrome (ACS) is one of the initial research themes of the HIC. ACS is the term for a group of cardiovascular diseases where the arteries that supply blood to the heart muscle become blocked, which can lead to a heart attack. There are over 80,000 hospital admissions in England each year for heart attack - around one admission every six minutes.
Troponins are a group of proteins that help regulate the pumping of the heart and are released into the bloodstream during a heart attack. Patients with suspected heart attack usually undergo a troponin blood test.
It has previously been assumed that higher levels of troponin mean a higher risk of dying. Additionally, it has been unclear how to manage patients who have small troponin rises, particularly if they do not have other symptoms associated with heart disease or a heart attack.
The ACS theme, led by the NIHR Imperial Biomedical Research Centre and Imperial College Healthcare NHS Trust, set out collect data on demographics and biochemistry, echocardiogram and angiogram results for all patients who had a troponin test ordered. Once the data discovery process had been completed, a dataset was formed consisting of de-identified information on 250,000 patients from the participating HIC sites.
Understanding troponin levels
The first big research finding for the theme, and in fact from the HIC as a whole, is from a study investigating troponin level, age and mortality.
The TROP-RISK study found that a raised troponin level was associated with an increase in risk of death in people of any age with suspected heart attack, with the increased risk of death occurring very soon after a high troponin level was detected. This link was seen even if the troponin result was only slightly raised.
The study, published in the BMJ, also showed that that regardless of age, the higher the level of troponin in the blood, the higher the risk of death in patients with a heart attack. The results suggest that even a small rise in troponin in any age group is clinically significant and can indicate underlying health problems.
However, the team also found that, contrary to what they expected, a very high level of troponin in the blood in patients with a heart attack was associated with a lower risk of dying. A possible reason is that patients with very high troponin levels are more likely to have a type of heart attack that can be treated by an operation to improve blood flow to the heart.
There are now 15 approved projects using the initial ACS dataset, and work is underway to expand the data collection to more organisations and to capture data in even more detail.
Impact on clinical care
The findings of the TROP-RISK study could have a significant influence on clinical practice. For example, clinicians will be able to use this information to help identify the risk of early death in patients who have a slightly raised troponin level following testing, so that those at highest risk may benefit from additional treatments.
Without the routinely captured patient data, creating a database of this size, consisting of this many patients, would simply have not been possible. The size of the database is what gives the researchers at the HIC the ability to answer complex research questions.
It also allows HIC researchers to conduct research at a much lower cost - a study the size of the TROP-RISK study would have been prohibitively expensive without the ACS dataset.
Learning from how we treat patients on a grand scale allows us to find out more about hospital care, and how it can be delivered more effectively and efficiently.
Jamil Mayet, Professor of Cardiology, Imperial College London
Amit Kaura, NIHR Academic Clinical Fellow, Imperial College London
Ben Glampson, NIHR Health Informatics Collaborative Programme Manager, Imperial College Healthcare NHS Trust
Dimitri Papadimitriou, Deputy Research Informatics Programme Manager, Imperial College Healthcare NHS Trust