Association Between Serum Bilirubin Levels And Urinary Microalbumin In Type 2 Diabetic Mellitus

Object: To investigate the association between serum bilirubin levels and urinary microalbumin(U-ALB)in patients with type 2 diabetes mellitus(T2DM).Methods: From June 1,2017 to May 31,2018,the study obtained766 patients with T2 DM diagnosed and treated at the Affiliated Hospital of Jining Medical University,and analyzed them retrospectively.Using the electronic medical record system,basic clinical information such as age,gender,presence of smoking,history of alcohol consumption,duration of diabetes mellitus and hypertension,etc,were obtained for the study population;patients’ measurements such as height and weight were obtained through physical examination and body mass index(BMI)was calculated;Collection includes routine blood,liver function,kidney function,blood lipids,glycated hemoglobin,U-ALB and other laboratory tests.Laboratory indexes were tested by fully automated analyzers except for U-ALB,which was measured by immunoturbidimetric method.According to the U-ALB results,there were two groups,normal group<30mg/L in 626 cases and abnormal group ≥30mg/L in 140 cases.The association of serum total bilirubin(TBIL),direct bilirubin(DBIL)and indirect bilirubin(IBIL)levels with U-ALB was also analyzed.Results: Smoothed curve fitting after adjusting for relevant confounders showed a U-shaped curve relationship between TBIL,DBIL,and IBIL levels and U-ALB.When TBIL<13.4umol/L,the risk of elevated U-ALB decreased by 21% for each 1umol/L increase in TBIL(OR=0.79,95% CI=0.71-0.88,P<0.01);when TBIL≥13.4umol/L,the risk of elevated U-ALB increased by 9% for each 1umol/L increase in TBIL(OR=1.09,95%CI=1.03～1.15,P<0.01);when DBIL<4.1umol/L,the risk of elevated U-ALB was reduced by 34% for each 1umol/L increase in DBIL(OR=0.66,95%CI=0.49～0.89,P<0.01);when DBIL≥4.1umol/L The risk of elevated U-ALB increased by 120% for each 1umol/L increase in DBIL(OR=2.20,95%CI=1.37～3.53,P<0.01);when IBIL was<7.3umol/L,the risk of elevated U-ALB decreased by 47% for each1umol/L increase in IBIL(OR=0.53,95%CI=0.41～ 0.70,P<0.01).Conclusions: In patients with T2 DM,TBIL,DBIL,and IBIL at physiological concentrations show a U-shaped curve relationship with U-ALB,and mild elevations of TBIL,DBIL,and IBIL in the normal range can reduce the risk of elevated U-ALB and thus may delay the progression of diabetic nephropathy.