Objective: To determine the correlation between serum fructosamine and self-monitoring blood glucose (SMBG) levels in gestational diabetes mellitus (GDM) patients treated by dietary control and to identify the cutoff level of serum fructosamine for determining poorly controlled GDM.

Materials and Methods: A cross-sectional study conducted between October 2021 and August 2022 at Queen Savang Vadhana Memorial Hospital that included 78 singleton pregnancies diagnosed with GDM assigned to diet therapy with lifestyle modification. The daily home SMBG was performed following the standard protocol and the serum fructosamine was measured one month after starting dietary control. The correlation between serum fructosamine and means of SMBG were analyzed. The receiver operating characteristics (ROC) curve was plotted to identify the cutoff level of serum fructosamine for predicting poorly controlled GDM based on SMBG levels. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the cutoff level were calculated.

Results: The correlation between serum fructosamine and SMBG were 0.436 (p<0.001) and 0.618 (p<0.001) in pre-prandial and post-prandial glucose levels, respectively. The poorly controlled SMBG group had serum fructosamine greater than the well-controlled group with a mean of 165.7±35 and 132.8±23 μmol/L (p<0.001). The ROC curve showed that using 160 μmol/L as the optimal cutoff level to determine poorly controlled GDM had 72.7% sensitivity, 88% specificity, 50% PPV, 95.2% NPV, and 85.9% accuracy.

Conclusion: The serum fructosamine was very useful for monitoring dietary control of GDM in terms of drawing blood less frequently, convenient, and more economical. An optimal cutoff point for screening a poorly controlled GDM was 160 mol/L.

Keywords: Gestational diabetes mellitus; Serum fructosamine; Self-monitoring blood glucose

DOI: 10.35755/jmedassocthai.2024.1.13929

Received 1 October 2023 | Revised 8 December 2023 | Accepted 14 December 2023