Relation of Direct, Indirect, and Total bilirubin to Adverse Long-term Outcomes Among Patients With Acute Coronary Syndrome.

Bilirubin is known as an antioxidant. However, there have been controversies over whether bilirubin is protective against cardiovascular disease or not. In addition, no study has examined the association between subtypes of total bilirubin (direct bilirubin [DB] and indirect bilirubin [IDB]) and long-term outcomes of acute coronary syndrome (ACS) patients. We included 533 consecutive patients with ACS. All the patients were followed up for the composite end point of cardiac death, revascularization, and acute heart failure. At a median follow-up of 2.4 years, Kaplan-Meier curve demonstrated that higher serum DB levels were significantly associated with major adverse cardiac events (MACE) (p <0.05). However, total bilirubin (TB) and IDB were not associated with MACE by Kaplan-Meier analysis. Cox analysis showed that high TB and DB were associated with increased risk of MACE in ACS even after adjustment of cardiovascular risk factors. The receiver operating characteristic curve illustrated that DB had a predictive value of MACE in ACS. In conclusion, we firstly reported that high TB and DB but not IDB were associated with increased risk of MACE in Chinese ACS, and the prognostic value of DB was superior to that of TB or IDB.