Association of Malondialdehyde and Total Antioxidant Capacity with Renal Function in Patients Undergoing Maintenance Hemodialysis: A Case–Control Study

Abstract

Background: Chronic kidney disease (CKD) is a progressive disorder characterized by irreversible loss of renal function and is associated with persistent oxidative stress and impaired antioxidant defense. Maintenance hemodialysis, although indispensable for patients with end-stage kidney disease, may further exacerbate oxidative stress by enhancing reactive oxygen species (ROS) generation and reducing circulating antioxidant levels, thereby contributing to cardiovascular complications and disease progression.

Objective: To evaluate oxidative stress biomarkers and total antioxidant capacity (TAC) in patients with chronic kidney disease undergoing maintenance hemodialysis and compare the findings with healthy controls.

Materials and Methods: This hospital-based case–control study included 40 CKD patients receiving maintenance hemodialysis and 40 healthy controls. Venous blood samples were collected after obtaining written informed consent and Institutional Ethics Committee approval. Serum urea, blood urea nitrogen (BUN), creatinine, uric acid, sodium, potassium, chloride, malondialdehyde (MDA), and TAC were estimated using standard biochemical methods. MDA was measured by the thiobarbituric acid reactive substances (TBARS) assay, while TAC was assessed using the Ferric Reducing Antioxidant Power (FRAP) assay. Statistical analysis was performed using the independent-samples Student’s t-test and Pearson’s correlation coefficient. A two-tailed p-value < 0.05 was considered statistically significant.

Results: CKD patients undergoing hemodialysis showed significantly higher serum urea (90.04±6.4 vs. 27.8±3.9 mg/dL), BUN (42.0±3.0 vs. 13.0±1.8 mg/dL), creatinine (9.5±1.4 vs. 0.8±0.1 mg/dL), uric acid (10.2±1.3 vs. 5.1±0.7 mg/dL), potassium (4.8±0.7 vs. 4.2±0.3 mEq/L), chloride (102.6±3.9 vs. 100.5±1.6 mEq/L), and MDA (8.6±2.0 vs. 2.9±0.6; p<0.001), whereas serum sodium (136.0±3.1 vs. 139.5±1.9 mEq/L) and TAC (0.7±0.2 vs. 1.7±0.09; p<0.001) were significantly reduced compared with controls. MDA showed a strong positive correlation with dialysis duration (r = 0.87) and significant positive correlations with creatinine (r = 0.507) and uric acid (r = 0.37). TAC demonstrated a significant positive correlation with estimated glomerular filtration rate (r = 0.64).

Conclusion: CKD patients undergoing maintenance hemodialysis exhibit marked oxidative stress, evidenced by increased lipid peroxidation and diminished antioxidant capacity, along with significant renal dysfunction and electrolyte disturbances. Assessment of MDA and TAC may serve as useful biomarkers for monitoring oxidative stress and disease progression in patients undergoing maintenance hemodialysis.