Correlation Of Serum Bilirubin With Diabetic Nephropathy And Its Systemic Inflammatory Markers

Objective:The purpose of this study is to investigate the correlation between serum bilirubin levels and type 2 diabetic kidney disease,and to further discover the significance of this result for the prevention and treatment of diabetic kidney disease.At the same time,we will also investigate the correlation between serum bilirubin and systemic inflammatory markers.Methods:A cross-sectional research was performed to continuously recruit 417 diabetic patients who were hospitalized in the Second Hospital of Shandong University from October 2018 to September 2020.We collected general information such as gender,age,smoking history,drinking history,diabetes duration,blood pressure,waist-hip ratio,body mass index(BMI),and past medical history.We also collected the detected neutrophil count,lymphocyte count,platelet count,blood glucose,blood lipids,serum bilirubin(TBIL),cystatin C(CysC),glycosylated hemoglobin(HbAlc),serum creatinine(Cr),β2-microglobulin(β2-MG),estimated glomerular filtration rate(eGFR),uric acid(UA),urinary microalbumin/creatinine ratio(UACR)and other biochemical indicators.Diabetic kidney disease(DKD)was diagnosed when UACR≥30mg/g and/or eGFR<60 ml/min/1.73m2.We divided the subj ects into DKD group and non-DKD group,and compared the differences between the two groups using t test or rank sum test.Patients were divided into low,intermediate,and high groups according to tertiles of TBIL.We used the chi-square test for trend to describe the trend of the incidence of DKD with the concentration of TBIL.The correlations between TBIL and systemic inflammatory markers platelet count/lymphocyte count(PLR),neutrophil count/lymphocyte count(NLR),general information,and other biochemical indicators were analyzed by Pearson or Spearman correlation analysis.At the same time,we used multivariate Logistic regression method to analyze the risk factors of DKD and to clarify the relationship between PLR,NLR,serum TBIL and DKD.Patients were grouped according to the tertiles of PLR(T1-3)for comparison of TBIL and other indicators.Multivariate stepwise regression analysis was used to analyze the correlation between PLR and TBIL after adjustment for other factors.Results:We compared the indicators of the DKD group(131 cases)and the non-DKD group(286 cases).We found that age,gender,waist-to-hip ratio,systolic blood pressure,duration of diabetes,history of stroke,HbAlc,low-density lipoprotein cholesterol(LDL-C),and UA were statistically significant between groups(all p values<0.05).Compared with the non-DKD group,the serum TBIL in the DKD group was significantly lower,but the NLR and PLR were significantly higher.Their differences were statistically significant(all p values<0.05).We grouped by tertiles of serum TBIL and found that the prevalence of DKD decreased with increasing serum TBIL concentrations(p<0.05).Correlation analysis showed that serum TBIL was associated with PLR(r=-0.332,p<0.001),UACR(r=-0.192,p<0.001),CysC(r=-0.118,p=0.016),β2-MG(r=-0.117,p=0.017)were negatively correlated.Serum TBIL was positively correlated with eGFR(r=0.181,p<0.001),but it had no significant correlation with NLR(r=0.071,p=0.146).Multivariate Logistic regression analy sis showed that the PLR of DKD was significantly increased before serum TBIL was adjusted.When serum TBIL was further corrected,serum TBIL was a protective factor for DKD(p<0.05),while PLR was not significantly correlated with DKD.The results also showed that the duration of diabetes,gender,diabetic retinopathy,systolic blood pressure,HbA1c,LDL-C,UA and NLR were independent risk factors for DKD(p<0.05).From the tertile grouping according to PLR,we found that with the increase of PLR,serum TBIL and eGFR gradually decreased(p<0.05),while β2-MG(p<0.001),UACR(p<0.001),CysC(p=0.001)showed a gradual upward trend with the increase of PLR.Multiple stepwise regression analysis showed that serum TBIL was independently negatively correlated with PLR.Conclusions:The occurrence of DKD in T2DM patients was accompanied by a decrease in serum TBIL,and an increase in the inflammatory markers PLR and NLR.PLR and NLR are independent risk factors for DKD,and serum TBIL is a protective factor for DKD.In the T2DM population,PLR was independently negatively correlated with serum TBIL.