Clinical Effect of Sex-Specific Cutoff Values of High-Sensitivity Cardiac Troponin T in Suspected Myocardial Infarction

Importance: It is currently unknown whether the uniform (universal clinical practice for more than 2 decades) or 2 sex-specific cutoff levels are preferable when using high-sensitivity cardiac troponin T (hs-cTnT) levels in the diagnosis of acute myocardial infarction (AMI).

Objective: To improve the management of suspected AMI in women by exploring sex-specific vs uniform cutoff levels for hs-cTnT.

Design, Setting, and Participants: In an ongoing prospective, diagnostic, multicenter study conducted at 9 emergency departments, the present study evaluated patients enrolled from April 21, 2006, through June 5, 2013. The participants included 2734 adults presenting with suspected AMI. Duration of follow-up was 2 years, and data analysis occurred from June 5 to December 21, 2015.

Interventions: The final diagnosis was centrally adjudicated by 2 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).

Main Outcomes and Measures: Diagnostic reclassification in women and men using sex-specific vs the uniform cutoff level in the diagnosis of AMI.

Results: Of the 2734 participants, 876 women (32%) and 1858 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 emergency department 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 3 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 2 women was upgraded from unstable angina to AMI, and the diagnosis in 1 man was downgraded from AMI to unstable angina. These diagnostic results were confirmed when using 2 alternative pairs of uniform and sex-specific cutoff values.

Conclusions and Relevance: The uniform 99th percentile should remain the standard of care when using hs-cTnT levels for the diagnosis of AMI.