Serum total bilirubin levels and disease severity in patients with stable coronary artery disease

Association Between Serum Bilirubin, Lipid Levels, and Prevalence of Femoral and Carotid Atherosclerosis: A Population-Based Cross-Sectional Study

BACKGROUND

Bilirubin may prevent lipid peroxidation and have important antiatherosclerotic effects. We determined associations of serum bilirubin and lipid with peripheral atherosclerosis.

METHODS

We included 4290 participants (35% men; median age, 60 years) from the southeast China who underwent B-mode ultrasound examination. Increased intima-media thickness or a focal structure encroaching into the arterial lumen by at least 0.5 mm or >50% of the surrounding intima-media thickness value was regarded as having atherosclerosis. Fasting serum bilirubin and lipid levels were measured. Cholesterol/(HDL [high-density lipoprotein] cholesterol+bilirubin), and LDL (low-density lipoprotein cholesterol)/(HDL+bilirubin) ratios were calculated. Unconditional and multinomial logistic regression models were used to examine associations of bilirubin or lipid with prevalence of peripheral atherosclerosis. Mediation analyses were performed to assess the effect of bilirubin on atherosclerosis risk mediated via lipid.

RESULTS

Compared with participants with the lowest levels of bilirubin, those with the highest tertile were less likely to have carotid or femoral atherosclerosis (odds ratios were 0.55-0.74). The highest levels of bilirubin significantly reduced the odds of concurrent carotid and femoral atherosclerosis by 35% to 45%. Participants with the highest levels of cholesterol, LDL, cholesterol/(HDL+bilirubin), and LDL/(HDL+bilirubin) ratios had 2.8- to 3.7-fold increased odds of concurrent carotid and femoral atherosclerosis. LDL accounted for 25.65% of the total bilirubin-atherosclerosis association. LDL and cholesterol mediated the associations between direct bilirubin and atherosclerosis (proportion: 20.40%, 9.67%, respectively).

CONCLUSIONS

Increased serum bilirubin levels are inversely associated with the prevalence of carotid or femoral atherosclerosis. LDL and cholesterol may mediate these associations.

Role of bilirubin in the prognosis of coronary artery disease and its relationship with cardiovascular risk factors: a meta-analysis

Background

Bilirubin is a heme catabolism product with antioxidant, anti-inflammatory, and anti-apoptotic properties and is implicated in the prognosis of several diseases. This study evaluates the prognostic role of bilirubin in coronary artery disease (CAD) patients.

Methods

After identifying studies from the literature, meta-analyses were performed to achieve a) overall estimates of serum total bilirubin levels in patients with myocardial infarction (MI), non-MI CAD and healthy individuals; b) odds ratios (OR) of adverse outcomes between higher and lower total bilirubin levels; c) standardized mean difference (SMD) in total bilirubin levels in patients with high vs low CAD severity; and d) correlation between disease severity and total bilirubin. Metaregression analyses were performed to examine the relationship between cardiovascular risk factors and increasing quantiles of total bilirubin levels.

Results

Forty-three studies were identified. Pooled serum total bilirubin levels were 0.72 mg/dl [95% confidence interval (CI): 0.60, 0.83] in MI patients; 0.65 mg/dl [95% CI: 0.60, 0.69] in non-MI CAD patients; and 0.66 mg/dl [95% CI: 0.56, 0.75] in healthy individuals. Higher total bilirubin levels were associated with greater odds of adverse outcomes in MI patients (OR: 1.08 [95% CI: 0.99, 1.18]) but lower odds in non-MI CAD patients (OR: 0.80 [95%CI: 0.73, 0.88]). Compared to non-severe cases, total bilirubin levels were higher in patients with severe MI (SMD 0.96 [95% CI: − 0.10, 2.01]; p = 0.074) but were lower in severe non-MI CAD patients (SMD − 0.30 [95%CI: − 0.56, − 0.03]; p = 0.02). Total bilirubin levels correlated positively with MI severity (r = 0.41 [95% CI: 0.24, 0.59]; p < 0.01) but correlated negatively with non-MI CAD severity (r =  − 0.17 [95% CI: − 0.48, 0.14]; p = 0.28). Female sex was inversely associated with increasing quantiles of bilirubin (meta-regression coefficient: − 8.164 [− 14.531, − 1.769]; p = 0.016) in MI patients.

Conclusion

Prognostic role of bilirubin for CAD appears complicated, as different odds are observed for MI and non-MI CAD patients which weakens the case of causal involvement of bilirubin in CAD etiology or prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02899-w.

Prognostic Value of Serum Total Bilirubin after Percutaneous Coronary Intervention in Patients with Acute Coronary Syndrome

Backgrounds

Previous studies have reported a relationship between serum total bilirubin (STB) and coronary artery disease (CAD). However, the relationship between STB and prognosis of patients with acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI) remains inconclusive. The present study aimed to evaluate the relationship between STB level and prognosis of PCI in patients with ACS.

Methods

In total, 2850 ACS patients who underwent PCI at the Affiliated Zhongda Hospital of Southeast University from June 2009 to Jan 2017 were included in the study. Twenty-four-hour STB, 30-day, and 1-year postoperative major adverse cardiovascular events (MACE) were recorded. Subjects were assigned to one of three groups based on STB: Group A (STB ≤ 9.6 μmol/L), Group B (9.7 μmol/L < STB ≤ 15.4 μmol/L), and Group C (STB ≥ 15.5 μmol/L). COX survival analysis was subsequently used to investigate the relationship between the incidence of MACE and STB in the three groups.

Results

A total of 2770 subjects were successfully followed up; within 1 year after PCI, 115 (4.15%) subjects died and 191 (6.90%) subjects experienced MACE. One-year follow-up results showed that the incidence of MACE decreased significantly as STB increased; the risk of Group A was 2.002 times that of Group C (95% CI: 1.342-2.986). Cardiac mortality also decreased with increasing STB; the risk of Group A was 3.403 times that of Group C (95% CI: 1.319-8.785).

Conclusion

Lower mortality and MACE incidence rates were found in patients with higher STB within 1 year. Therefore, STB is highly recommended as an independent long-term prognosis predictor of PCI in patients with ACS.