Evaluation of the fructosamine test in obesity: consequences for the assessment of past glycemic control in diabetes

✍ Scribed by Christiane Broussolle; Francoise Tricot; Isabelle Garcia; Jacques Orgiazzi; Andre Revol

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 590 KB
• Volume: 24
• Category: Article
• ISSN: 0009-9120
• DOI: 10.1016/0009-9120(91)90586-4

✦ Synopsis

The effect of obesity in diabetic and nondiabetic states on serum fructosamine levels, as measured by the nitro blue tetrazolium reduction method, was investigated. In 26 nondiabetic obese subjects, the mean (SD) fructosamine (1.78 +-0.16 mmol/L.) and protein corrected fructosamine concentrations (25.7 +-2.5 p.mol/g) were significantly lower than in nondiabetic lean control subjects (2.06 --0.18 mmol/L and 30.5 --2.5 p.mol/g, respectively; p < 0.01). Hemoglobin A1C, blood glucose and serum protein concentrations were normal in obese subjects. Interference from hypertriglyceridemia, hemolysis, or drugs was excluded. In diabetic subjects, fructosamine correlated with hemoglobin A1C, but the leastsquares regression lines were different in 16 nonobese and in 19 obese patients, so that for the same hemoglobin A~C value, fructosamine level was 16% lower in obese compared to nonobese diabetic subjects. In vitro studies showed a significant decrease in ~4C-glucose incorporation in serum proteins of obese nondiabetic subjects compared to control subjects. Similarly, the rate of formation of fructosamine in sera of obese nondiabetic subjects incubated with 12 mmol/L and 30 mmol/L glucose concentrations was slower than in sera of control subjects. In conclusion, fructosamine is underestimated in obesity, both in diabetic and nondiabetic patients, and its validity as an index of glycemic control may be impaired in obese subjects. This decrease is due to an alteration in the glycation process itself.