High sensitivity cardiac troponin T and interleukin‐6 predict adverse cardiovascular events and mortality in anticoagulated patients with atrial fibrillation

Summary. There are limited data on the prognostic role of biomarkers in anticoagulated patients with atrial fibrillation (AF). We evaluated the prognostic value of high sensitivity TnT (hsTnT) and high‐sensitivity interleukin‐6 (hsIL6) in a large cohort of AF patients taking oral anticoagulant therapy (OAC) as both biomarkers have been associated with adverse cardiovascular events. Methods: We studied 930 patients (51% male; median age 76) with permanent/ paroxysmal AF who were stabilized (for at least 6 months) on OAC (INRs 2.0–3.0). Plasma hsTnT and hsIL6 levels were quantified by electrochemiluminescense immunoassay at baseline. Patients were followed‐up for up to 2 years, and adverse events (thrombotic and vascular events, mortality and major bleeding) were recorded. Results: At follow‐up, 96 patients (3.97%/year) died whilst 107 had an adverse cardiovascular event (3.14%/year). On multivariate analysis, high hsTnT and high hsIL6 remained significantly associated with prognosis even after adjusting for CHADS₂ score: HR 2.21 (1.46–3.35, P < 0.001) for high hsTnT and 1.97 (1.29–3.02, P = 0.002) for high hsIL6, for adverse cardiovascular events. For all‐cause mortality, the HRs were 1.79 (1.13–2.83, P = 0.013) and 2.48 (1.60–3.85, P < 0.001), respectively. The integrated discrimination index (IDI) values of clinical scores (CHADS₂ and CHA₂DS₂‐VASc) were improved by the addition of hsTnT and/or hsIL6 (all P < 0.05). Conclusion: In a large ‘real world’ cohort of anticoagulated AF patients, both hsTnT and hsIL6 levels provided prognostic information that was complementary to clinical risk scores for prediction of long‐term cardiovascular events and death, suggesting that these biomarkers may potentially be used to refine clinical risk stratification in AF.