Association of Serum Bilirubin and Serum Uric Acid with Glycemic Status in Type 2 Diabetes Mellitus

Background: Type 2 diabetes mellitus (T2DM) is a major public health problem affecting millions of people worldwide and its magnitude in developing countries including Bangladesh is rising rapidly. It is associated with multiple metabolic derangements that result in the excessive production of reactive oxygen species and oxidative stress. The major concern of health management in T2DM patients is to prevent diabetes-related complications which can only be achieved via strict glycemic control. Over the recent past it had been evident that serum bilirubin acts as a powerful antioxidant and upper limit of physiological ranges of serum bilirubin levels are beneficial and negatively associated with oxidative stress and glycemic status. Moreover, high serum uric acid plays an important role as an oxidative stress agent that is associated with poor glycemic control in diabetic subjects. Low serum bilirubin and high uric acid predicted a higher incidence for the development of T2DM and also had adverse impact on glycemic status. So, this study was designed to find out the association of serum bilirubin and uric acid with glycemic status among Type 2 diabetes mellitus subjects.

Objective: To evaluate the association of serum bilirubin and uric acid with glycemic status in Type 2 diabetes mellitus.

Materials and Methods: This cross-sectional analytical study was carried out in the department of Biochemistry, Sir Salimullah Medical College (SSMC), Dhaka from March, 2021 to February, 2022. A total number of 100 subjects were included in this study. Among them, 50 apparently healthy non-diabetic subjects age ranged from 30-59 years were considered as control group (Group A). Another 50 age and gender matched Type 2 diabetes mellitus patients without any complication were selected as study group (Group B). Ethical permission was taken from the Ethical Review Committee (ERC) of SSMC. All the study subjects were selected from the outpatient department of Medicine and Endocrinology, Sir Salimullah Medical College and Mitford Hospital, Dhaka. The study parameters were FPG, HbA1c, Serum bilirubin and serum uric acid. Estimation of study parameters were done in the Department of Biochemistry of SSMC, Dhaka. Statistical analysis was done by using SPSS version-22. Unpaired t test, Chi Square test, Pearson’s correlation test and Binary logistic regression were performed to analyze the data as applicable.

Results: Serum bilirubin level was significantly lower and uric acid level was significantly higher among diabetic subjects in comparison to healthy controls. Comparison of glycemic status (FPG and HbA1c) in between different quartiles of serum bilirubin and uric acid in diabetic subjects were observed. FPG and HbA1c levels were significantly higher in Q1 & Q2 compared to Q3 & Q4 of serum bilirubin. However, FPG and HbA1c levels found high in Q3 & Q4 than Q1 & Q2 of uric acid. Pearson’s correlation analysis showed significant negative correlation of serum bilirubin with FPG and HbA1c, whereas significant positive correlation of serum uric acid with FPG and HbA1c were observed in study subjects. Binary logistic regression was performed to show the association between several factors and diabetes which were expressed by the coefficients of logistic regression. The risk of diabetes for each factor was expressed as odds ratio (OR). Coefficient for serum bilirubin (showing inverse relation) was significant. In case of serum uric acid, coefficient showed significant positive relationship. Where serum uric acid was strongest predictor of diabetes with an odds ratio of 3.709.

Conclusion: Type 2 diabetic subjects have lower serum bilirubin and higher uric acid level than that of healthy subjects. Serum bilirubin has an inverse relationship with glycemic status (FPG and HbA1c), whereas uric acid shows positive correlation with glycemic status in diabetic subjects. Hyperuricemia appears to be a risk factor for development of Type 2 diabetes mellitus.