Investigation of the Relationship between Serum Uric Acid Levels and Hb A1c and Glomerular Filtration Rate in Patients with Type 2 Diabetes Mellitus

Objective: The aim of this study was to investigate the relationship between serum uric acid (SUA) level and hemoglobin A1c (Hb A1c) and estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes mellitus (T2DM). Materials and Methods: The study was conducted retrospectively by reviewing the files of patients diagnosed with T2DM aged 18 years and older. Patients were divided into two groups according to Hb A1c values: those with Hb A1c ≥7 and those with Hb A1c <7. Age, gender, uric acid, creatinine and HbA1c values and their correlations were analyzed. Results: A total of 510 patients were included in the study. Of the patients, 162 were female (31.76%) and 348 were male (68.24%). The mean age was 69.68±12.29 years in female patients and 66.14±12.34 years in male patients. Mean duration of DM was 10.22±9.64 years in female patients and 11.42±10.12 years in male patients. The mean Hb A1c value of 263 patients with Hb A1c <7 was 6.05±0.55 and the mean Hb A1c value of 247 patients with Hb A1c ≥7 was 9.08±1.91. When serum uric acid, creatinine and eGFR values (calculated according to the Modification of Diet in Renal Disease (MDRD) formula) were compared between the groups with high and low Hb A1c, a statistically significant difference was found between serum uric acid levels (p=0.002). When the correlation between uric acid, and eGFR in the groups with high and low HbA1c was analyzed, a statistically significant, strong negative correlation was found (p<0.001 r= -0.640). Conclusion: In T2DM patients, eGFR decreases as serum creatinine level increases, and eGFR decreases at approximately the same rate as serum uric acid level increases. This is independent of HbA1c. In other words, eGFR decreases as uric acid increases even if diabetes control is not impaired. This result reveals the importance of diet in T2DM patients.