LOW SERUM BILIRUBIN LEVELS IN WOMEN WITH THE ANTIPHOSPHOLIPID SYNDROME

The aim: To investigate the relationship between serum bilirubin level and the presence of the APS in women with a history of spontaneous miscarriages.

Materials and methods: Fifty six women aged 22-38 (median 27) years with a history of spontaneous miscarriages were divided into two groups: 33 women with the APS and 23 without. Patients were tested for the presence of lupus anticoagulant, anticardiolipin, anti-β2-glycoprotein 1, antiphospholipid antibodies and genetic thrombophilic defects.

Results: Groups were comparable by age, blood pressure, BMI, co-morbidity (anemia, heart abnormality, thyroid disease, overweight). Median serum total bilirubin levels were 7,2 μmol/L (interquartile range [5,8-9,7]) in women with the APS and 10,5 μmol/L (interquartile range [7,5-15,1]) in control group, p=0.005. The chance of detecting a total bilirubin level of less than 8 μmol/L is 4.1 times higher in the APS patients than in the control group (OR 4,1; 95% CI 1,274-13,213). Logistic regression analysis found a statistically significant association between total bilirubin and the presence of the APS (odds ratio, 0.856; 95% CI, 0.734-0.997, p =0.046). Patients with the APS had elevated serum C-reactive protein (medians 2,3 vs 1,1 mg/L, p=0.01) and fibrinogen (medians 2,8 vs 2,5 g/L, p=0.006) levels compared with controls. Correlation analysis revealed a significant correlation between all types of bilirubin and inflammatory markers.

Conclusions: All types of serum bilirubin (total, direct and indirect) are significantly reduced in women with APS, associated with higher inflammatory markers and lower levels of 25-hydroxyvitamin D, which may be the result of oxidative stress.