Troponin-T and age as predictors for mortality in patients with atrial fibrillation at the emergency department

Abstract

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Grants from Region Östergötland County Medical Research Council of Southeast Sweden Background Atrial fibrillation/flutter (AF) is a common heart arrhythmia and medical condition at the emergency room, making up approximately 1-2% of the visits and hospital admissions. Previous studies have shown an association between elevated Troponin-T levels and mortality (1). However, there is limited data in whether mildly elevated Troponin-T levels together with age correlates with an increased mortality. Purpose The purpose of this study was to analyse the usage of Troponin-T and its prognostic value for mortality together with age in patients with AF at the emergency department. Methods A comparison of when Troponin-T was used and when multiple sampling occurred was made. A comparison of Troponin-T together with age was also made to analyse potential associations with mortality. Patients were identified through the ICD-10 code for AF (I48) and the data was collected through medical records and diagnostic registers. Patients were divided in three groups based on Troponin-T (< 15 ng/L, 15-50 ng/L and > 50 ng/L) and four subgroups based on age (< 60, 60-69, 70-79 and > 80 years). Primary outcomes were all-cause mortality at 30 days and 1 year. The association between Troponin-T, age and mortality were analysed through hazard ratio (HR) with 95% confidence interval (CI). Results 771 patients with AF at the emergency room were included in this cohort study (median age 72, 44,6% female and median AF duration 1,3 years). There was a significant difference in Troponin-T levels between patients admitted to hospital compared to discharge (p < 0,001). All-cause mortality was 1,9% (n = 15) at 1 month and 7,7% (n = 59) at 1 year. The hazard ratio (HR) was 9,86 (95% CI 1,23-78,82, p = 0,031) for Troponin-T 15-50 ng/L and 32,98 (95% CI 3,85-282,29, p < 0,001) for Troponin-T > 50 ng/L at 30 days compared to Troponin-T < 15 ng/L. The HR at 1 year was 7,98 (95% CI 3,10-20,51, p < 0,001) for Troponin-T 15-50 ng/L and 20,88 (95% CI 7,52-57,98, p < 0,001) for Troponin-T > 50 ng/L compared to Troponin-T < 15 ng/L. For age, the HR at 1 year was 2,67 (95% CI 0,54-13,23, p = 0,229) for age 60-69 years, 3,59 (95% CI 0,82-15,80, p = 0,091) for age 70-79 years and 12,79 (95% CI 3,05-53,68, p < 0,001) for age > 80 years compared to age < 60 years. Conclusions Troponin-T appears to influence several decisions taken at the emergency room for patients with AF, such as whether admission or multiple sampling is required. Troponin-T and age appears to independently indicate the risk for all-cause mortality. Higher Troponin-T were also associated with increased mortality in most age groups.