Analysis Of The Relationship Between Serum Bilirubin Level And Retinopathy In Patients With Type 2 Diabetes Mellitus

Objective:To investigate the relationship between different subtypes of serum bilirubin and the risk of diabetic retinopathy(DR)in patients with different genders of type 2 diabetes mellitus(T2DM).Methods: From June 1,2017 to May 31,2019,1304 patients with T2 DM who were examined and diagnosed in the Department of Endocrinology of the affiliated Hospital of Jining Medical College were selected for retrospective study.The general clinical data of the study population were collected,including sex,age,history of smoking and drinking,previous history of chronic disease,family history of diabetes,course of DM,complications related to DM,menopause,etc.Weight,height,waist circumference and other measurement data were obtained through physical examination,and body mass index was calculated.Laboratory test indexes include blood routine,fasting blood glucose,glycosylated hemoglobin,liver function,kidney function,blood lipid,thyroid function,electrolyte,insulin and C-peptide release test,urine routine,urinary Microalbumin and so on.All patients were screened for fundus lesions by ophthalmologists,and based on the fundus photography results,the patients were segmented into DR and NDR group.All analyses were performed using Empower(R)and R.Results: In patients with T2 DM,the levels of total bilirubin,direct bilirubin and indirect bilirubin in DR group were significantly lower than those in NDR group.Univariate analysis showed that the levels of total bilirubin andindirect bilirubin were negatively correlated with the occurrence of DR(P <0.01).There was no significant correlation between the level of direct bilirubin and the occurrence of DR.Smooth curve fitting showed that there was a U-shaped relationship between the levels of total bilirubin and indirect bilirubin and the risk of DR in women,and a negative correlation between total bilirubin,indirect bilirubin and the risk of DR in men.The results of multiple regression analysis showed that in men total bilirubin increased by 1 μmol/L,the risk of DR decreased by 8%(OR=0.92,95%CI 0.88-0.98,P<0.01).Indirect bilirubin increased by 1 μmol/L,and the risk of DR decreased by 10%(OR=0.90,95%CI 0.84-0.96,P<0.01).In women,when TBIL<12.8 umol/L,for every 1umol/L increase in total bilirubin,the risk of DR is reduced by 17%(OR=0.83,95%CI0.72~0.95,P<0.01);when TBIL≥12.8 umol/L,for every 1umol/L increase in total bilirubin,the risk of DR is increased by 10%(OR=1.10,95%CI 1.01-1.20,P<0.05).When IDBIL<9.8 μmol/L,for every 1umol/L increase in indirect bilirubin,the risk of DR is reduced by 20%(OR=0.80,95 % CI 0.68-0.94,P<0.01).When IDBIL ≥ 9.8 umol/L,for every 1umol/L increase in indirect bilirubin,the risk of DR is increased by 13%(OR=1.13,95 % CI 1.01-1.25,P<0.05).According to the stratified analysis of menopause,the results showed that there was a non-linear relationship between TBIL,IDBIL and the occurrence of DR in postmenopausal patients.There was no correlation between TBIL,IDBIL and DR in premenopausal patients.In postmenopausal women,when TBIL<8.1 umol/L,for every 1umol/L increase in total bilirubin,the riskof DR is reduced by 20%(OR=0.80,95%CI 0.68-0.94,P<0.01).When TBIL≥8.1 umol/L,the difference was not statistically significant(OR=0.99,95%CI0.92~1.05,P>0.05);when IDBIL<10.9umol/L,for every 1umol/L increase in indirect bilirubin,the risk of DR is reduced by 18%(OR=0.82,95%CI 0.71~0.95,P<0.01).When IDBIL ≥ 10.9umol/L,for every 1umol/L increase in indirect bilirubin,the risk of DR is increased by 6%,but the difference was not statistically significant(OR=1.06,95%CI 0.94~1.20,P>0.05).Conclusions: This study shows that there are gender differences in total bilirubin,indirect bilirubin and DR in patients with type 2 diabetes,and there is no significant correlation between direct bilirubin and the risk of DR.In female patients,there is a non-linear relationship between the levels of total bilirubin and indirect bilirubin and the risk of DR,especially in postmenopausal patients,too high or too low levels of total bilirubin and indirect bilirubin will increase the risk of DR.In male patients,total bilirubin and indirect bilirubin were negatively correlated with the risk of DR.