Even a small spike in a heart attack-related protein may raise the risk of a premature death, scientists say.
Data from 250,000 people showed having raised troponin levels tripled the odds of death within three years.
And it was linked to a 10-fold higher risk in adults aged between 18 and 29, Imperial College London researchers found.
Doctors in A&E units across the UK already use troponin tests to examine if a patient has experienced a heart attack.
The protein is found in the muscles of the heart and regulates its contractions. It is released into the bloodstream if the heart is damaged.
Even a small increase in a protein linked to heart attacks could increase the risk of an early death across all ages, scientists say
Experts say an increase in troponin levels should be investigated urgently because it could indicate other underlying heart problems.
Patients may not have any symptoms usually tied to heart disease or a heart attack – but would benefit from medications such as statins.
Dr Amit Kaura, lead author, said: ‘This is the first study to address the implications of raised troponin in a real world large sample of patients.
‘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 team analysed anonymised cardiovascular data of thousands of patients who had troponin tests in five leading NHS trust hospitals.
Patients were grouped by age and their troponin results were compared with their outcomes over a period of three years.
Even when doctors have not diagnosed a heart attack, raised troponin signified an increased risk of death, results revealed.
Almost half (46 per cent) of patients over the age of 80 with a raised troponin level died within three years – mostly within six months.
A surprising findings however, was that patients with high levels of troponin actually had a lower risk of dying.
This may be because these people were more likely to have had surgery for a severe heart attack, improving their blood flow and survival rates.
The study, published in the British Medical Journal, is one of the first to suggest any increase at all could be dangerous.
Dr Kaura and team wrote: ‘Regardless of age, a raised troponin level is an important clinical signal that should not be dismissed lightly.’
They also warned a ‘conservative wait and see approach’ may not be appropriate, given the risks.
Dr Kaura 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.’
WHAT CAN MEASURING TROPONIN LEVELS IN THE BLOOD SHOW?
Measuring cardiac troponin levels in the blood allows doctors to diagnose a heart attack or other heart-related conditions more effectively – and provide immediate treatment.
In healthy people, troponin levels are low enough to be undetectable.
If you’ve experienced chest pain but troponin levels are still low 12 hours after the chest pain started the possibility of a heart attack in unlikely.
High levels are an immediate red flag. Troponin levels can elevate within three to four hours after the heart has been damaged and can remain high for up to 14 days.
Troponin levels are measured in nanograms per milliliter. Normal levels fall below the 99th percentile in the blood test.
If troponin results are above this level, it may be an indication of heart damage or heart attack.