Increased fructosamine in non-diabetic rheumatoid arthritis patients: role of lipid peroxides and glutathione.

Modification of proteins by non-enzymatic glycation is one of the underlying factors known to play a major role in the pathogenesis of many clinical disorders. Glycation of plasma proteins is enhanced by elevated glucose concentrations. However, increased fructosamine has been documented in rheumatoid arthritis patients without any history of diabetes. Collective evidence reveals that malondialdehyde and reduced glutathione can modulate the glycation process. This study was undertaken to unravel the possible association of malondialdehyde and glutathione with fructosamine in rheumatoid arthritis patients. A case-control study was performed on 15 rheumatoid arthritis patients and 15 control subjects. Whole blood glutathione, plasma malondialdehyde, fructosamine and fasting glucose were analyzed in both groups. Partial correlation analysis was performed to predict the independent association of malondialdehyde, glutathione and fasting glucose on fructosamine. In rheumatoid arthritis patients, while fructosamine and malondialdehyde levels were significantly increased, glutathione levels were significantly decreased compared with controls. With partial correlation analysis, fructosamine was found to have a significant positive correlation with malondialdehyde and a negative correlation with glutathione. These data suggest that plasma fructosamine levels are closely associated with malondialdehyde and glutathione in rheumatoid arthritis patients, warranting extra precaution in interpreting fructosamine as a measure of glycemic control in these patients.