Uniform threshold to rule out MI works well in male, female patients

A uniform cardiac troponin threshold to identify myocardial infarction (MI) risk demonstrates safety and efficacy in both male and female patients, reports a study.

Consecutive patients with possible MI were included in this study, which assessed the implementation of a uniform rule-out threshold (<5 ng/L) with a high-sensitivity cardiac troponin I assay.

Researchers determined the proportion of low-risk patients discharged from the emergency department and incidence of MI or cardiac death at 30 days. They derived and validated sex-specific thresholds, and then stratified the proportion of female and male patients as low-risk relative to the uniform threshold.

Care was guided using a uniform threshold in 16,792 patients (mean age 58 years, 46 percent female). The uniform threshold identified more female than male patients as having a low risk (73 percent vs 62 percent) of developing MI.

However, the proportion of low-risk patients discharged from the emergency department was similar (81 percent for both sexes), with fewer than five (<0.1 percent) patients having a subsequent MI or cardiac death at 30 days.

Use of sex-specific thresholds, compared with a uniform threshold, resulted in a higher proportion of female patients (61.8 percent vs 65.9 percent) and a lower proportion of male patients (54.8 percent vs 47.8 percent) being identified as low-risk.

“Sex-specific rule-out thresholds should be considered, but their impact on effectiveness and safety may be limited,” the researchers said.