Assessment of Oxidative Stress and Antioxidant Enzyme Status in Patients with Type 2 Diabetes Mellitus: Correlation with Glycemic Control

Abstract

Background: Type 2 diabetes mellitus (T2DM) is associated with hyperglycaemia-driven oxidative stress and depletion of antioxidant defences, but the behaviour of individual antioxidant enzymes, particularly catalase, is inconsistently reported across studies.

Objective: To assess plasma malondialdehyde (MDA) and antioxidant enzyme status — superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and total antioxidant capacity (TAC) — in patients with T2DM and correlate these with glycemic control.

Methods: A case-control study was conducted at a tertiary care centre in Indore, India, in 51 T2DM patients and 60 healthy controls (following exclusion of 9 enrolled patients for antioxidant supplement use). MDA, SOD, catalase, GPx and TAC were estimated by validated spectrophotometric assays and correlated with glycated haemoglobin (HbA1c) using Spearman's coefficient; independent predictors were assessed by multivariable linear regression.

Results: MDA was significantly higher (2.69 ± 0.62 versus 1.49 ± 0.24 nmol/mL, P<0.001) and SOD, catalase, GPx and TAC significantly lower in patients than controls (P≤0.007). MDA correlated strongly with HbA1c (r=0.777, P<0.001); catalase showed the weakest correlation (r=-0.377, P=0.006) and did not differ significantly between good- and poor-control subgroups (P=0.063), while the remaining three antioxidant markers did (P≤0.020).

Conclusion: Oxidative stress is significantly elevated and antioxidant enzyme status significantly reduced in T2DM, tracking glycemic control closely for MDA, SOD, GPx and TAC; catalase behaves inconsistently, a pattern consistent with prior literature and warranting further mechanistic study.