The impact of sex differences on 3-year outcomes of patients with non-ST-segment elevation myocardial infarction after successful stent implantation according to symptom-to-balloon time

BACKGROUND: Because no data are available, we compared the 3-year outcomes of patients with non-ST-elevation myocardial infarction (NSTEMI) based on sex and symptom-to-balloon time (SBT). METHODS: This study included 4910 patients who were divided into two groups based on SBT: SBT <48 h (n = 3,293, 67.1%) and SBT ≥48 h (n = 1,617, 32.9%). The primary outcome was all-cause death during the 3-year follow-up period. The secondary outcome was major adverse cardiac events (MACE), defined as all-cause death, recurrent myocardial infarction, or repeat coronary revascularization. RESULTS: After adjustment, the in-hospital mortality rates for males and females in the SBT <48 h and SBT ≥48 h groups were similar. During a 3-year follow-up period, females in the SBT <48 h group had significantly higher rates of all-cause death (adjusted hazard ratio [aHR], 1.482; P = 0.006), cardiac death (CD, aHR, 1.617; P = 0.009), and MACE (aHR, 1.268; P = 0.024) than those males in the same groups. Females and males in the SBT ≥48 h group did not differ significantly in the primary and secondary outcomes. In males, the rates of all-cause death (P = 0.008) and CD (P = 0.024) were significantly higher in the SBT ≥48 h group than in the SBT <48 h group. CONCLUSIONS: This study has identified a higher 3-year mortality rate in female patients with NSTEMI and SBT <48 h compared to their male counterparts. As such, a more preventive approach may be required to reduce mortality in these female patients.