The U-shaped association between normal-range serum bile acid levels and prognosis of Coronary Heart Disease

Background: Previous studies have shown that serum total bile acid levels are associated with both the presence of Coronary Heart Disease and the severity of coronary artery lesions. Coronary Heart Disease progression frequently involves an imbalance in bile acid metabolism. This study aims to evaluate the predictive value of total bile acid levels for the occurrence of major adverse cardiovascular events in patients with Coronary Heart Disease. Method: A total of 2,974 patients with Coronary Heart Disease who met the inclusion criteria were categorized into four groups based on the quartiles of their total bile acid levels: Group 1 (0.2-1.9 µmol/L, n = 760), Group 2 (1.9-3.1 µmol/L, n = 758), Group 3 (3.1-5.1 µmol/L, n = 741), and Group 4 (5.1-10 µmol/L, n = 715). Survival differences among the groups were evaluated using Kaplan-Meier curves. Multivariate Cox regression analysis was performed to assessed their associations. Restricted cubic spline models were employed to investigate potential nonlinear relationships. Subgroup interaction and incremental predictive value analyses were additionally performed. Results: Over a median follow-up period of 75 months, Group 2 exhibited a significantly lower incidence of major adverse cardiovascular events compared to the other groups. Kaplan-Meier survival analyses also demonstrated that participants in Group 2 exhibited significantly higher cumulative survival rates free of major adverse cardiovascular events compared to those in the other groups. Multivariate Cox regression revealed that both higher and lower total bile acid levels were associated with an increased risk of major adverse cardiovascular events (HRQ1 = 1.91, p