The influence of pressure injury risk on the association between left ventricular ejection fraction and all-cause mortality in patients with acute myocardial infarction 80 years or older

Abstract

BACKGROUND: We aimed to investigate whether the pressure injury risk mediates the association of left ventricular ejection fraction (LVEF) with all-cause death in patients with acute myocardial infarction (AMI) aged 80 years or older. METHODS: This retrospective cohort study included 677 patients with AMI aged 80 years or older from a tertiary-level hospital. Pressure injury risk was assessed using the Braden scale at admission, and three risk groups (low/minimal, intermediate, high) were defined according to the overall score of six different variables. LVEF was measured during the index hospitalization for AMI. All-cause death after hospital discharge was the primary outcome. RESULTS: Over a median follow-up period of 1,176 d (interquartile range [IQR], 722–1,900 d), 226 (33.4%) patients died. Multivariate Cox regression analysis showed that reduced LVEF was associated with an increased risk of all-cause death only in the high-risk group of pressure injury (adjusted hazard ratios [HR]=1.81, 95% confidence interval [CI]: 1.03–3.20; P=0.040), but not in the low/minimal- (adjusted HR=1.29, 95%CI: 0.80–2.11; P=0.299) or intermediate-risk groups (adjusted HR=1.14, 95%CI: 0.65–2.02; P=0.651). Significant interactions were detected between pressure injury risk and LVEF (adjusted P=0.003). The cubic spline with hazard ratio plot revealed a distinct shaped curve relation between LVEF and all-cause death among different pressure injury risk groups. CONCLUSIONS: In older patients with AMI, the risk of pressure injury mediated the association between LVEF and all-cause death. The classification of older patients for both therapy and prognosis assessment appears to be improved by the incorporation of pressure injury risk assessment into AMI care management.