A new analysis of patients' heart data has shown that even a slight increase in a protein linked to heart attacks, called troponin, is linked to an increased risk of early death at all ages.
Clinicians use troponin testing, alongside other investigations, to determine whether a patient is having a heart attack and to inform treatment choices. It has been assumed that the higher the amount of troponin in the blood, the higher the risk of death in all age groups.
In a large new study, published in the British Medical Journal, researchers from the National Institute of Health Research Health Informatics Collaborative (NIHR-HIC) led by Imperial College Healthcare NHS Trust and Imperial College London found that a raised troponin level was associated with an increase in risk of death in all age groups. This was seen even if the troponin result was slightly raised, with the increased risk of death occurring very early.
They also showed that that regardless of age, the higher the amount of troponin in the blood, the higher the risk of death in patients with a heart attack. The results suggests that even a small rise in troponin in all age groups is clinically significant and can indicate underlying health problems.
However, the team also found that, contrary to what they expected, very high levels of troponin in the blood in patients with a heart attack was associated with a lower risk of dying. They suggest that a possible reason is that patients with very high troponin levels are more likely to have a type of heart attack which can be treated by an operation to improve blood flow to the heart and therefore reduce the risk of dying.
Amit Kaura, lead author of the research and NIHR Clinical Research Fellow at Imperial College London, said: "There have been many advances in treating heart disease yet it remains the leading cause of death in the UK and around the world. This is the first study to address the implications of raised troponin in a real world large sample of patients across a wide range of ages. Doctors will be able to use this information to help identify the risk of early death in patients who have a troponin level measured; this could lead to interventions at a much earlier stage in a wider group of patients than are currently treated."
The researchers found that in young patients (18-29 years), those whose blood showed a raised troponin had a 10-fold higher risk of death than those whose blood did not. This increased risk fell with age, reaching 1.5 times the risk in patients over the age of 90. Nevertheless, even in very elderly patients, raised troponin in the blood signifies a higher risk of dying. Over the age of 80, almost half of patients with a raised troponin level died within three years.
They also found that even when doctors do not think the primary problem is a heart attack, the presence of a raised troponin in the blood signifies an increased risk of death. Therefore, the troponin result provides meaningful information in all age groups, regardless of the underlying problem.
Troponins are a group of proteins that helps regulate the contractions of the heart and skeletal muscle. The heart releases troponin into the bloodstream following an injury to the heart such as a heart attack. High levels of troponin usually mean there is a problem with the heart.
Doctors carry out a blood test to measure the levels of troponin in the blood which enables them to assess the damage caused to the heart and how patients are responding to treatment. It has previously been assumed that higher levels of troponin, mean a higher mortality risk.
However, 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 researchers behind today's study wanted to examine the impact of raised troponin across different ages, specifically the very elderly. They also wanted to investigate the significance of very small troponin levels, compared with larger levels, on patients' prognosis.
The team analysed the anonymised cardiovascular data of more than 250,000 patients who had troponin tests at National Institute for Health Research Health Informatics Collaborative sites including: Imperial College Healthcare NHS Trust, University College London Hospitals NHS Foundation Trust, Oxford University Hospitals NHS Foundation Trust, King's College Hospital NHS Foundation Trust and Guy's and St Thomas' NHS Foundation Trust from 2010-2017. The team grouped the patients by age and compared their troponin results with their outcomes over a period of three years.
The team are currently designing a trial to see if patients with a raised troponin, without a heart attack, may benefit from cardiac treatments including cholesterol lowering medication, such as a statin.
The work is part of the NIHR Health Informatics Collaborative (NIHR-HIC) which Imperial College London and Imperial College Healthcare NHS Trust is part of. The NIHR-HIC was established to improve the quality and availability of patient data for research purposes. This will enable researchers to gain new insights into areas such as the effectiveness of different treatments and what factors influence patient outcomes and recovery.
The collaboration is between five leading NHS trusts, each of which has a strong relationship with a partner university.
The ultimate aim of all this work is to find ways to improve the experience and outcomes of patients in the NHS.
The study was funded by NIHR Imperial Biomedical Centre (BRC) and was conducted using National Institute for Health Research Health Informatics Collaborative (NIHR HIC) data resources.
This research is an example of the work carried out by Imperial College Academic Health Science Centre, a joint initiative between Imperial College London and three NHS hospital trusts. It aims to transform healthcare by turning scientific discoveries into medical advances to benefit local, national and global populations in as fast a timeframe as possible.
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Notes to Editors
1. About Imperial College Academic Health Science Centre (AHSC) The AHSC is a partnership between Imperial College London, The Institute of Cancer Research, Imperial College Healthcare NHS Trust, Royal Brompton & Harefield NHS Foundation Trust and the Royal Marsden NHS Foundation Trust, based in West London. Established in 2007, it was the first AHSC to be created in the UK and was formally designated by the Department of Health in 2009. The partnership brings together multi-disciplinary research and education from across all faculties at the College with the resources and critical mass of the three Trusts to advance discovery and innovation within healthcare. The purpose of Imperial College AHSC is to utilise excellence in research and education to transform health outcomes, and support the UK's globally competitive position in healthcare related industries by increasing societal and economic gain. The AHSC is nested within Imperial College Health Partners, the Academic Health Science Network for North West London, which will ensure that discoveries and innovations are applied on a national and global scale.
2. About Imperial College London
Imperial College London is one of the world's leading universities. The College's 16,000 students and 8,000 staff are expanding the frontiers of knowledge in science, medicine, engineering and business, and translating their discoveries into benefits for society.
Founded in 1907, Imperial builds on a distinguished past - having pioneered penicillin, holography and fibre optics - to shape the future. Imperial researchers work across disciplines to improve health and wellbeing, understand the natural world, engineer novel solutions and lead the data revolution. This blend of academic excellence and its real-world application feeds into Imperial's exceptional learning environment, where students participate in research to push the limits of their degrees. Imperial collaborates widely to achieve greater impact. It works with the NHS to improve healthcare in west London, is a leading partner in research and education within the European Union, and is the UK's number one research collaborator with China. Imperial has nine London campuses, including its White City Campus: a research and innovation centre that is in its initial stages of development in west London. At White City, researchers, businesses and higher education partners will co-locate to create value from ideas on a global scale.
3. About Imperial College Healthcare NHS Trust
Imperial College Healthcare NHS Trust is one of the largest hospital Trust's in England, providing acute and specialist healthcare for a population of nearly two million people. The Trust has five hospitals - Charing Cross, Hammersmith, Queen Charlotte's & Chelsea, St Mary's and The Western Eye - as well as community services.
4. The National Institute for Health Research (NIHR) is the nation's largest funder of health and care research. The NIHR:
* Funds, supports and delivers high quality research that benefits the NHS, public health and social care * Engages and involves patients, carers and the public in order to improve the reach, quality and impact of research * Attracts, trains and supports the best researchers to tackle the complex health and care challenges of the future * Invests in world-class infrastructure and a skilled delivery workforce to translate discoveries into improved treatments and services * Partners with other public funders, charities and industry to maximise the value of research to patients and the economy The NIHR was established in 2006 to improve the health and wealth of the nation through research, and is funded by the Department of Health and Social Care. In addition to its national role, the NIHR supports applied health research for the direct and primary benefit of people in low- and middle-income countries, using UK aid from the UK government.
This work uses data provided by patients and collected by the NHS as part of their care and support and would not have been possible without access to this data. The NIHR recognises and values the role of patient data, securely accessed and stored, both in underpinning and leading to improvements in research and care.