Circulating Total Bilirubin and Long-Term Prognosis in Patients With Previous Myocardial Infarction

BACKGROUND: Although experimental studies have demonstrated the protective role of total bilirubin (TBil) in cardiovascular diseases, several previous clinical observations are controversial. More importantly, no data are currently available regarding the relation of TBil to major adverse cardiovascular events (MACE) in patients with previous myocardial infarction (MI). OBJECTIVES: This study sought to explore the association between TBil and long-term clinical outcomes in patients with previous MI. METHODS: A total of 3,809 patients who are post-MI were consecutively enrolled in this prospective study. Cox regression models using HRs and CIs were applied to investigate associations between the TBil concentration category (group 1: bottom to median tertiles within the reference range; group 2: top tertile; group 3: above reference range) and main outcome (recurrent MACE) as well as secondary outcomes (hard endpoints and all-cause mortality). RESULTS: During the 4-year follow-up period, 440 patients (11.6%) suffered from recurrent MACE. Kaplan-Meier survival analysis showed the lowest MACE incidence in group 2 (P < 0.001). When compared with the reference group (group 1) in multivariable analysis, a J-shaped association was apparent for MACE, with decreased risk in group 2 (HR: 0.76; 95% CI: 0.59-0.96) and elevated risk in group 3 (HR: 1.29; 95% CI: 1.03-1.61). Similar associations were identified regarding hard endpoints and all-cause mortality. Moreover, TBil demonstrated incremental discriminatory strength when added to the predictive model. CONCLUSIONS: In this prospective cohort study with long-term follow-up, higher TBil levels within the physiological range reduced the incidence of long-term cardiovascular events in patients who are post-MI.