Yoo Lee Kim, Yong Wook Cho, Seok Won Park, Yun Kyung Cho, Hwa Young Lee, In Hyun Kim, Jong Gun Won, Hye Sun Jun, Ho Taek Lee, Seog Ki Lee, Sang Jong Lee
Korean Diabetes J. 2000;24(2):267-280. Published online January 1, 2001
BACKGROUND Although 75 g-OGTT at PPT 6 week is necessary to diagnose persistent PPT glucose intolerance (PPGI) in GDM patients, it 1s difficult to perform this test because many patients drop-out during the follow-up period. Thus we tested whether OGTT done at PPT 1 week can substitute OGTT at PPT 6 week in diagnosing PPGI in GDM patients. METHOD: In 370 GDM patients, 75 g-OGTT was performed at PPT 1 week and repeat OGTT was done in 196 patients at PPT 6 week. Results of OGTT were classified as normal glucose tolerance(NGT), impaired glucose tolerance(IGT), and diabetes mellitus (DM) according to National Diabetes Data Group(NDDG) criteria. Changes in glucose tolerance state between PPT 1 and 6 week were assessed, and the predictability of clinical characteristics for these changes were investigated by logistic regression analysis. RESULTS: Among 370 GDM patients who performed OGTT at PPT 1 week, 79.4% had NGT, 12.2% had IGT, and 8.4% had DM. 53% (196/370) of subjects repeated OGTT at PPT 6 week. In OGTT at PPT 6 week, 77.6% (152/196, 140/149 in NGT, 4/26 in IGT and 8/21 in DM) were in the same glucose tolerance state as at PPT 1 week. The glucose tolerance improved in 14.8% (29/196, 16/26 in IGT and 13/21 in DM) and deteriorated in 7,6% (15/196, 9/149 in NGT and 6/26 in IGT). 94%(140/149) of patients who had NGT at PPT 1 week had NGT at PPT b week and 48.9/o (23/47) of patients who had abnormal glucose tolerance at PPT 1 week had abnormal glucose tolerance at PPT 6 week. Mean fasting plasma glucose level on OGTT became lower at PPT 1 week than during pregnancy (4.6+/-0,8 vs 5.1+/-1.2mmol/L, p<0.05) and became higher at PPT 6 week than at PPT 1 week (5.4+/-1.1 vs 4.6+/-0.8 mmol/L, p<0.05). Mean plasma glucose level at 2 hour after glucose load was significantly lower at PPT 6 week than at PPT 1 week (7.2+/-2.7 vs 8.3+/-2.5 mmol/L). When the subjects were grouped into NGT, IGT, and DM according to glucose tolerance state at PPT 6 week, the NGT group already showed normal glucose tolerance at PPT 1 week. The IGT and DM group showed slightly lower glucose levels at PPT 1 week than during pregnancy but became high to the level during pregnancy at PPT 6 week. In the patients group showing deterioration in glucose tolerance state between PPT 1 and 6 week, prevalence of insulin treatment was higher (63.4% vs 9.4, 20.7%), the gestational age at diagnosis of GDM were lower (25.0+/-6.2 week vs 29.8+/-3.3, 29.9+/-4,8 waek), and prepregnant weight was higher (113.4+/-21.2% vs 102.5+/-12.4, 102.4+/-14.6%) than those in the patients groups showing no change and improvement in glucose tolerance state, Weight gain until diagnosis of GDM during pregnancy(5.7+/-4.4kg vs 9.4+/-3.4kg) and weight change between prepregnancy and PPT 5 week(-1,3+/-3.5kg vs 1.5+/-29kg) was smaller in the deterioration group than those in the no change group. Logistic regression analysis performed using improvement and deterioration of glucose tolerance state between PPT 1 and 6 week as an outcome of interest revealed that an earlier diagnosis of GDM and a smaller weight at PPT 6 week than prepregnant weight were independent predictors for deterioration of glucose tolerance between PPT 1 and 6 week. In conclusion, OGTT done at PPT 1 week can substitute OGTT at PPT 6 week in a large subgroup of GDM patients who has NGT at PPT 1 week without any risk factors for deterioration in glucose tolerance.