Sex-Specific Cutoff Values of hs-CTnT in Suspected MI
What are the diagnostic and prognostic changes in women and men induced by sex-specific cutoff values for high-sensitivity cardiac troponin T (hs-cTnT) in patients with suspected acute myocardial infarction (AMI)?
The Advantageous Predictors of Acute Coronary Syndrome Evaluation Study was a prospective, diagnostic, multicenter study conducted at nine emergency departments (EDs) that evaluated patients enrolled from April 21, 2006, through June 5, 2013. The participants included 2,734 adults presenting with suspected AMI. Duration of follow-up was 2 years, and data analysis occurred from June 5 to December 21, 2015. The final diagnosis was centrally adjudicated by two independent cardiologists using all available information, including measurements of serial hs-cTnT blood concentrations twice: once using the uniform 99th percentile cutoff value level of 14 ng/L and once using sex-specific 99th percentile levels of hs-cTnT (women, 9 ng/L; men, 15.5 ng/L). The main outcome measure was diagnostic reclassification in women and men using sex-specific versus the uniform cutoff level in the diagnosis of AMI.
Of the 2,734 participants, 876 women (32%) and 1,858 men (68%) were included. Median (interquartile range) age was 68 (55-77) and 59 (48-71) years, respectively. With the use of the uniform cutoff value, 127 women (14.5%) and 345 men (18.6%) received a final diagnosis of AMI. Among these, at ED presentation, levels of hs-cTnT were already above the uniform cutoff value in 427 patients (sensitivity, 91.3% [95% CI, 85%-95.6%] in women vs. 90.7% [95% CI, 87.1%-93.5% in men]; specificity, 79.2% [95% CI, 76.1%-82.1%] in women vs. 78.5% [95% CI, 76.4%-80.6%] in men). After readjudication using sex-specific 99th percentile levels, diagnostic reclassification regarding AMI occurred in only three patients: 0.11% (95% CI, 0.02-0.32) of all patients and 0.6% (95% CI, 0.13-1.85) of patients with AMI. The diagnosis in two women was upgraded from unstable angina to AMI, and the diagnosis in one man was downgraded from AMI to unstable angina. These diagnostic results were confirmed when using two alternative pairs of uniform and sex-specific cutoff values.
The authors concluded that uniform 99th percentile should remain the standard of care when using hs-cTnT levels for the diagnosis of AMI.
This multicenter trial enrolling patients presenting to the ED with suspected AMI quantified the magnitude of diagnostic and prognostic reclassifications in women and men associated with the clinical use of sex-specific cutoff levels for hs-cTnT in the early diagnosis of AMI. The study reports very high and well-balanced sensitivity and specificity of the uniform cutoff level for hs-cTnT at ED presentation in women and men with suspected AMI. Based on this and other available data, the uniform 99th percentile should remain the standard of care when using hs-cTnT levels for the diagnosis of AMI.
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