Fig. 2

Restricted Cubic Spline (RCS) Curves for the Association of Admission Blood Pressure with Short-term and Long-term Mortality. Adjusted Hazard Ratios (HRs) for the associations of admission systolic blood pressure (SBP) and diastolic blood pressure (DBP) with 30-day and 2-year all-cause mortality are shown via RCS models with 3 knots. The models were adjusted for: (1) Demographics: age, gender, type of AAD; (2) Medical history: Hypertension, coronary heart disease, type 2 diabetes mellitus, Marfan syndrome, heart bypass surgery, heart valve replacement; (3) Clinical biomarkers: NTproBNP and hsTNT at admission; (4) Presenting signs and symptoms at admission: Heart rhythm regularity, aortic aneurysm, thoracodynia, back pain, abdominal pain, syncope, pericardial effusion, and myocardial infarction. Figure 2 − 1 and 2–2 represent the dose-response relationship between admission SBP and DBP and the risk of 30-day mortality. Figure 2-3 and 2-4 represent the relationship between admission SBP and DBP and the risk of 2-year mortality. The solid blue lines indicate the estimated HRs, and the shaded light-blue areas represent the corresponding 95% confidence intervals (CIs). The pink histograms in the background reflect the density distribution of blood pressure values among the study participants. The horizontal dashed line is positioned at HR = 1.0 as the reference point. For 30-day mortality, the associations for SBP (P overall = 0.069) and DBP (P overall = 0.215) did not reach statistical significance. For 2-year mortality, significant non-linear associations were observed for both SBP (P overall = 0.009, P nonlinear = 0.008) and DBP (P overall = 0.020, P nonlinear = 0.005), indicating a J-shaped prognostic relationship.