Abstract
BACKGROUND: The aspartate aminotransferase-to-platelet ratio index (APRI) is an effective non-invasive marker for chronic liver dysfunction. Given that heat stroke patients often suffer from poor prognosis due to multi-organ involvement, with liver injury and coagulation dysfunction being of particular concern, this study aims to investigate whether APRI can comprehensively reflect liver injury and coagulation dysfunction in heat stroke patients and explore its relationship with 28-day mortality. METHODS: This retrospective study analysed electronic medical records from patients treated at 57 grade A tertiary hospitals in China from May 2005 to May 2024. The primary outcome was 28-day mortality, and the secondary outcome was 7-day mortality. Restricted cubic splines (RCS) were utilized to visualize the relationship between APRI and 28-day mortality risk. The independent association between APRI and outcomes was assessed using Cox proportional hazards models, with multivariable analyses controlling for confounding factors. The predictive ability of APRI for outcomes was evaluated using receiver operating characteristic (ROC) curves. RESULTS: A total of 450 eligible patients were included, with 71 deaths occurring within 28 days. RCS analysis showed a positive correlation between APRI and 28-day mortality. Participants were divided into higher (APRI ≥ 15.14) and lower (APRI < 15.14) APRI groups. Cox proportional hazards models indicated that individuals with higher APRI had a significantly increased 28-day mortality rate (HR 5.322, 95% confidence interval [CI] 2.642-10.720, p < 0.0001). Subgroup and interaction analyses confirmed the robustness of the core findings. Additionally, the areas under the ROC (AUROC) for APRI predicting 28-day mortality was 0.823 (95% CI 0.772-0.875), significantly higher than the AST to ALT ratio (0.526, 95% CI 0.448-0.605) and total bilirubin (0.694, 95% CI 0.623-0.765). CONCLUSION: APRI is an independent predictor of early mortality risk in heat stroke.