Long-term outcome of postpartum glucose metabolism among patients with gestational hyperglycemia and its risk factors

Objective To explore the long-term outcome of postpartum glucose metabolism among patients with gestational hyperglycemia and its risk factors. Methods Patients with gestational hyperglycemia, diagnosed by 100 g oral glucose tolerance test(OGTT) during 24th to 28th gestation week between 2010 and 2012 and giving the childbirth in Peking Union Medical College Hospital, were included. The glucose metabolism outcomes were evaluated by 75 g OGTT. The risk factors influencing the glucose metabolism outcome and the glucose metabolism parameter changes between the pregnancy term and now were also analyzed. Results Forty patients with gestational hyperglycemia were included. The follow-up time was postpartum 5-8 years and (6.83±0.74)years on average. Among them, 3 patients were diagnosed with type 2 diabetes and 9 patients were diagnosed with impaired glucose intolerance. The overall rate of abnormal glucose metabolism was 30 percent. The third-hour glucose of OGTT larger than 7.45 mmol/L and the area under the glucose curve(Glu AUC) during OGTT larger than 24.875 mmol×h/L were the risk factors for the abnormal glucose metabolism outcome, with the odds ratio of 5.769 (95% confidence interval 1.064-31.270, P=0.042) and 12.5(95% confidence interval 2.226-70.187, P=0.004). Using the 2-hour glucose larger than 8.25 mmol/L and 3-hour glucose larger than 7.45 mmol/L in the OGTT of midtrimester to judge the glucose state in the follow-up visit can achieve the diagnostic efficacy with the sensitivity of 75%, specificity of 82%, positive prediction value of 64% and negative prediction value of 88%. Comparing with now, the fasting glucose in the midtrimester was lower ([5.49±0.43] vs. [4.55±0.47] mmol/L, P<0.001), the fasting insulin in the midtrimester was higher (12.30[6.35, 16.55] vs. 8.31[6.79, 12.00] μIU/ml, P=0.048), HOMA-β in the midtrimester was higher (202.67[145.71, 335.71] vs. 85.41[78.63, 112.13], P<0.001). Conclusion The third-hour glucose larger than 7.45 mmol/L and the glucose area under the curve larger than 24.88 mmol×h/L in the OGTT of midtrimester are the risk factors for the abnormal glucose state in the postpartum long-term follow-up. The combination of the second-hour and the third-hour glucoses in the 100 g OGTT of midtrimester can help to predict the postpartum long-term glucose state. Key words: gestational hyperglycemia; postpartum long-term glucose metabolism