Prognostic Importance of Sex-Specific Cardiac Troponin T 99th Percentiles in Suspected Acute Coronary Syndrome

OBJECTIVE: Cardiac troponin levels differ between the sexes, with higher values commonly seen in men. The use of sex-specific troponin thresholds is, thus, subject of an ongoing debate. We assessed whether sex-specific cardiac troponin T (cTnT) 99th percentiles would improve risk prediction in patients admitted to Swedish coronary care units due to suspected acute coronary syndrome. METHODS: In this retrospective register-based study (48,250 patients), we investigated the prediction of all-cause mortality and the composite of cardiovascular death or nonfatal myocardial infarction within 1 year using the single 99th cTnT percentile (> 14 ng/L) or sex-specific cTnT 99th percentiles (> 16/9 ng/L). RESULTS: A total of 1078 men (3.0%) with cTnT 15-16 ng/L and 1854 women (8.4%) with cTnT 10-14 ng/L would have been reclassified regarding their cTnT status by the means of sex-specific 99th percentiles. The prevalence of cardiovascular risk factors and crude event rates increased across higher cTnT strata in both men and women. Multivariable-adjusted Cox models, however, did not demonstrate better risk prediction by sex-specific 99th percentiles. Assessing cTnT as a continuous variable demonstrated an increase in multivariable-adjusted risk starting at levels around 10-12 ng/L in both men and women. CONCLUSIONS: We found no evidence supporting the use of sex-specific cTnT 99th percentiles in men and women admitted because of suspected acute coronary syndrome. This likely depends on sex-specific differences in disease mechanisms associated with small cTnT elevations. From a pragmatic perspective, a single cTnT cutoff slightly below 14 ng/L seems to be preferable as a threshold for medical decision-making. (C) 2016 Elsevier Inc. All rights reserved.