New research finds that raised levels of a protein called troponin are a "highly clinically meaningful" indicator of death risk, regardless of age or underlying cause.
The medical community recognizes the protein troponin as a biomarker for diagnosing heart attacks. Furthermore, previous studies have found a link between higher troponin levels and plaque rupture, acute coronary obstruction, and poorer myocardial perfusion — a measure of how well blood circulates through the heart.
Troponins are regulatory proteins that play a key role in the heart's muscle contractions.
Now, new research finds that even a slight increase in the levels of this protein is consistently associated with a higher risk of death among all age groups.
Amit Kaura is the lead author of the new research and a clinical research fellow at Imperial College London in the United Kingdom. His and his team's findings appear in the BMJ.
Death risk 10 times higher
Kaura and colleagues examined the data of more than 250,000 people in an effort to gauge the link between age, troponin level, and mortality.
Between 2010 and 2017, doctors had measured the troponin levels of each of the study participants, whose ages ranged from 18 years to over 90 years. The scientists clinically followed these individuals for 3 years.
Overall, the researchers found a dose-response link between high levels of troponin in the blood and early death risk, meaning that the higher the troponin levels were, the higher the risk of death. This association held regardless of age.
When looking specifically at different age groups, the analysis revealed that young adults — that is, those between the ages of 19 and 29 years — with raised troponin levels were 10 times more likely to die than those whose blood did not have elevated levels of the protein.
The risk declined gradually with age, with people over the age of 90 years with raised troponin levels being 1.5 times more likely to die than others of a similar age.
However, almost half of the participants with high troponin levels who were over 80 years of age died within 3 years, note the researchers, confirming the notion that high troponin levels signal a higher likelihood of dying.
Finally, the results also revealed a paradox: In people who had experienced a heart attack, extremely high levels of troponin were linked with a lower death risk.
The researchers explain that this may be because a higher proportion of these participants were suitable candidates for an operation that improves blood flow to the heart.
Overall, the authors conclude, "A positive troponin result is, therefore, highly clinically meaningful, regardless of age, with the excess mortality associated with a raised troponin level being heavily concentrated in the first few weeks."
The findings, say the researchers, emphasize the fact that troponin levels may be a useful tool for assessing longevity, even in those who have not had a heart attack.
Furthermore, the research team is currently working on a clinical trial to examine whether cardiovascular treatments such as statins improve the heart health of those with raised troponin levels.
Kaura comments on the findings, saying, "There have been many advances in treating heart disease, yet it remains the leading cause of death in the U.K. 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," the researcher adds.
"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."