Prevalence and significance of troponin elevations in patients without acute coronary disease.

Background: Cardiac troponin T and I are important diagnostic and prognostic markers in patients with acute coronary syndrome (ACS). Troponin elevations in various non-ACS scenarios have been documented, but few studies have been conducted on the general hospitalized population, none compared the diagnostic performance of troponin I and T.
Methods and Results: Patients aged >18years (n=1097), consecutively admitted to a district hospital, were included in the study. Blood samples were collected at admission and analysed with three different troponin assays. Serum was available in 92.2%, giving a study population of 1012 patients (mean age 61.6years, 510 (50.4%) female). ACS was diagnosed among 125 (12.4%) of the patients. Remaining patients were admitted with a broad spectrum of medical and surgical conditions. Of the total population, sc-cTnI was above the 99th percentile in 93 (9.2%), hs-cTnI was above the 99th percentile in 80 (7.9%) and hs-cTnT was above the 99th percentile in 400 (39.5%) of the patients (p<0.001 for all differences). Hs-cTnT was stronger correlated with estimated glomerular filtration rate (r [2]=0.13 vs r [2]=0.06) and haemoglobin (r [2]=0.1 vs r2=0.02) than with hs-cTnI, none were correlated with C-reactive protein (r [2]=0.04 vs r [2]=0.02). The correlation between ln(hs-cTnT) and ln(hs-cTnI) was better in ACS patients than in non-ACS patients (r [2]=0.79 vs r [2]=0.47, p<0.001).
Conclusion: Hs-cTnT was elevated above the 99th percentile in more than one third of the non-ACS patients, while hs-cTnI and sc-cTnI were elevated in approximately one tenth. The correlation between hs-cTnT and hs-cTnI concentrations was significantly stronger in ACS patients than in non-ACS patients.
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