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Elevated circulating troponin linked to AF risk in older adults
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In ambulatory older adults, circulating troponin T levels appear to be significantly associated with incident atrial fibrillation, according to recent findings.
In a prospective cohort study, researchers evaluated 4,262 participants in the Cardiovascular Health Study (CHS), a longitudinal analysis of adults aged 65 years or older without AF at baseline. At enrollment, participants completed a standardized questionnaire pertaining to various health and behavioral risk factors, and also underwent a physical examination. The researchers confirmed patient self-reports through baseline examination, review of medical records or surveys of treating physicians, with follow-up measurements obtained 2 to 3 years later for 2,870 patients.
Patients were contacted for follow-up every 6 months after initial assessment. Incident AF was determined through ECG results, hospital discharge diagnoses and Medicare files during a median follow-up of 11.2 years.
Cardiac troponin T was undetectable (< 3 ng/L) in 1,419 patients. During follow-up, incident AF occurred in 1,363 participants. Researchers observed a primarily linear association between baseline troponin levels and incident AF after adjusting for age, race, sex, AF risk factors and HF status over time, with a cutoff of 3.25 Log-ng/L, corresponding to a baseline of 24.53 ng/L (HR = 1.39; 95% CI, 1.26-1.53 per log unit increase).
After adjustment for demographics, traditional risk factors and incident HF, higher baseline levels of cardiac troponin T were linked to increased risk for incident AF (HR = 1.75; 95% CI, 1.48-2.08 for third troponin T level tertile vs. undetectable levels). Further adjustment for inflammatory biomarkers and hemodynamic strain did not eliminate the significance of this association (HR = 1.38; 95% CI, 1.16-1.65).
Analysis according to change in cardiac troponin T levels among the 2,870 patients with evaluable follow-up data indicated a significantly greater risk for incident AF with increased troponin T (HR = 1.03; 95% CI, 1.01-1.04 per 1 ng/L per year increment).
“The findings suggest an association of processes which would release troponins from the myocyte into the circulation in ambulatory older adults with incident AF beyond traditional risk factors, incident HF, inflammation and hemodynamic strain,” the researchers concluded. “Such processes involve but are not limited to cardiomyocyte injury, myocardial damage, proteolysis or myocardial contractile protein turnover in HF.” –by Jennifer Byrne
Disclosure: One researcher reports receiving honoraria, consulting and grant support from Roche Diagnostics and Siemens Healthcare Diagnostics, along with consulting and grant support from BG Medicine and Critical Diagnostics.
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