Correlation Between Serum Bilirubin And Serum Lipids In Patients With Rheumatoid Arthritis

Objective To measure serum bilirubin levels in patients with rheumatoid arthritis(RA),including total bilirubin(TBIL)and direct bilirubin(DBIL),serum lipid levels,including total cholesterol(TC),triglyceride(TG),high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)levels and other related immune parameters such as C reactive protein(CRP),rheumatoid factor(RF)and erythrocyte sedimentation rate(ESR)and analyze the correlation between them.To investigate the relationship between the levels of serum bilirubin and the levels of serum lipids and the related immunity factors in RA patients.Methods Serum samples from 115 patients with RA(including 64 cases of RA activity patients and 51 cases of RA remission patients)and 62 healthy volunteers were collected and analyzed.Serum bilirubin levels(including TBIL and DBIL)were measured by diazo method.Serum lipid levels(including TC,TG,HDL-C and LDL-C)were detected by enzyme colorimetric assay.The levels of serum C reactive protein(CRP)and rheumatoid factor(RF)were measured by immune rate scattering turbidimetry.The erythrocyte sedimentation rate(ESR)was measured by the method of Wei’s method.Results The levels of serum TBIL and DBIL in patients with RA active stage and RA remission stage were significantly lower than those in healthy control group(P<0.01).However,there was no significant difference in serum bilirubin levels between RA patients in active stage and RA patients in remission period(P>0.05).The levels of serum TC and HDL-C in patients with RA active stage were significantly lower than those in healthy control group(P<0.01),and serum HDL-C levels in patients with RA active stage were significantly lower than those in RA remission stage(P<0.01).But there was no significant difference in serum TC level between patients in active stage of RA and patients in remission stage of RA(P>0.05).The serum TG levels of RA patients in the active stage group were significantly higher than those in the healthy control group and the RA patients in the remission stage group(P<0.01).There was no significant difference in serum LDL-C levels in patients with RA active stage(P>0.05).The levels of serum TC and HDL-C in patients with RA remission period were significantly lower than those in healthy control group(P<0.05 and P<0.01).However,there were no significant differences in serum TG and LDL-C between patients in RA remission stage group and healthy control group(P>0.05).Further calculations showed that the atherosclerosis index(TC/HDL-C)in patients with RA active stage was significantly higher than that in healthy control group and the RA patients in the remission stage group(P<0.01).However,there was no significant difference in atherosclerosis index(TC/HDL-C)between the patients in the RA remission stage group and the healthy control group(P>0.05).The correlation analysis between variables showed that the levels of serum TBIL(r = 0.203,P<0.05)and DBIL(r = 0.232,P<0.05)in RA patients were significantly positively correlated with serum HDL-C levels,and serum levels of DBIL in RA patients were significantly negatively correlated with atherosclerosis index(TC/ HDL-C)(r =-0.237,P<0.05).However,the levels of serum bilirubin in RA patients were not correlated with serum TC,TG and LDL-C levels(P>0.05).Serum TBIL levels(r =-0.240,P<0.01)and serum DBIL levels(r =-0.255,P<0.01)in RA patients were significantly negatively correlated with serum CRP levels.Serum levels of TBIL(r =-0.438,P<0.01)and DBIL(r =-0.411,P<0.01)in RA patients were significantly negatively correlated with ESR.The levels of serum HDL-C in patients with RA were significantly negatively correlated with the levels of CRP(r =-0.374,P<0.01)and ESR(r =-0.249,P<0.01).Serum TC levels in patients with RA were significantly negatively correlated with serum CRP levels(r =-0.312,P<0.01).There was a significant positive correlation between serum CRP level and atherosclerosis index(TC/HDL-C)in RA patients(r = 0.202,P<0.05).However,there was no correlation between ESR level and serum TC level and atherosclerosis index(TC/HDL-C)in patients with RA(P>0.05).There was no correlation between serum TG and LDL-C levels and the levels of CRP and ESR in patients with RA(P>0.05).The levels of serum bilirubin and lipid in patients with RA were not correlated with RF(P>0.05).Conclusion Serum bilirubin(TBIL and DBIL)levels were significantly lower in patients with RA,indicating that bilirubin had protective effect on RA.The levels of serum TC and HDL-C were significantly decreased in RA patients,and the decrease of HDL-C was related to disease activity.The levels of serum TBIL and DBIL in patients with RA were positively correlated with serum HDL-C levels.There was a negative correlation between serum DBIL levels and atherosclerosis index(TC/HDL-C).The levels of serum bilirubin and some lipid components in patients with RA were correlated with inflammatory markers CRP and ESR.