Causes of Troponin Elevation and Associated Mortality in Young Patients

Background: While increased serum troponin levels are often due to myocardial infarction, increased levels may also be found in a variety of other clinical scenarios. Although these causes of troponin elevation have been characterized in several studies in older adults, they have not been well characterized in younger individuals. Methods: We conducted a retrospective review of patients 50 years of age or younger who presented to two large tertiary care centers between January 2000 and April 2016 with elevated serum troponin levels. Patients with prior known coronary artery disease were excluded. The cause of troponin elevation was adjudicated via review of electronic medical records. All-cause death was determined using the Social Security Administration's death master file. Results: Of the 6081 cases meeting inclusion criteria, 3574 (58.8%) patients had a myocardial infarction, while 2507 (41.2%) had another cause of troponin elevation. Over a median follow-up of 8.7 years, all-cause mortality was higher in patients with non-myocardial infarction causes of troponin elevation compared with those with myocardial infarction (adjusted HR: 1.30, 95% CI: 1.15-1.46, p<0.001). Specifically, mortality was higher in those with central nervous system pathologies (adjusted HR: 2.21, 95% CI: 1.85-2.63, p<0.001), non-ischemic cardiomyopathies (adjusted HR: 1.66, 95% CI: 1.37-2.02, p<0.001), and end stage renal disease (adjusted HR: 1.36, 95% CI: 1.07-1.73, p=0.013). However, mortality was lower in patients with myocarditis compared with those with an acute myocardial infarction (adjusted HR: 0.43, 95% CI: 0.31-0.59, p<0.001). Conclusion: There is a broad differential for troponin elevation in young patients, which differs based on demographic features. Most non-myocardial infarction causes of troponin elevation are associated with higher all-cause mortality compared with acute myocardial infarction.