Critical evaluation of the diagnosis of Gestational Diabetes Mellitus

Critical evaluation of the diagnosis of Gestational Diabetes Mellitus (GDM) Simon Weitzman, MD, MPH Critical evaluation of the diagnosis of Gestational Diabetes Mellitus (GDM) Diagnostic methods and criteria Screening strategies Maternal and offspring outcomes Critical evaluation of the diagnosis of Gestational Diabetes Mellitus (GDM) Diagnostic methods and criteria Screening strategies Maternal and offspring outcomes Diagnostic Methods for GDM  1-hr. Oral Glucose Challenge Test (GCT)  Oral Glucose Tolerance Test (OGTT) World Health Organization (WHO) National Diabetes Data Group (NDDG) Coustan Modification Diagnostic criteria for GDM Method WHO (75 gr) NDDG (100 gr) Coustan (100 gr) Criteria (mg/dl) FPG 1 hr. 2 hr. 3 hr. 140 105 95 190 180 200 165 145 155 140 FPG: Fasting plasma glucose Critical evaluation of the diagnosis of Gestational Diabetes Mellitus (GDM) Diagnostic methods and criteria Screening strategies Maternal and offspring outcomes Screening strategies for GDM  The approach One-step approach Two-step approach The 50 gr. GCT (Cutoff >186 mg/dl) Sensitivity: 38.2%  Specificity: 93.3%    Positive Predictive Value: 78.6 % Negative Predictive Value : 70.0 % The 50 gr. GCT (Cutoff >186mg/dl)     Sensitivity: 38.2% Specificity: 93.3% Positive Predictive Value:19.5% Negative Predictive Value: 97.2% Screening strategies for GDM  The population screening  Universal  High risk groups screening Universal versus high risk strategy Universal screening • 57.4% agreed to screening • 27.7 % GCT positive have abnormal OGTT • Non-participants have more risk factors High Risk Group Screening •Would miss > 40% of GDM Universal screening in the Negev 70 % of Jewish and 57% of Bedouins agreed to screening  GCT only in 49% of women  OGTT only in 10%  Overall non- participation: 40%  Critical evaluation of the diagnosis of Gestational Diabetes Mellitus (GDM) Diagnostic methods and criteria Screening strategies Maternal and offspring outcomes Influence of GDM on the later development of diabetes in the child  Hyperglycemia affects fetal beta-cell function in animals Intrauterine nutritional deprivation and maternal hyperglycemia increase the risk of diabetes in later life  Maternal and offspring outcomes Characteristic LGA (%) Gestational age (w) Hospital days Normal OGTT 34 39 3.7 GDM 38 39.2 3.9 Perinatal characteristics of women with GDM, according to risk factors Characteristic Risk Factors OR(95%CI) Yes Cesarean section (%) Macrosomia (%) Shoulder Dystocia (%) Insulin therapy(%) 38 33 7 30 No 35 17 13 28 1.6 (0.7-3.7) 2.4 (0.9-6.7) 0.5 (0.1-2.1) 1.1 (0.4-2.7) Plasma glucose levels in non obese, and obese women with previous GDM, after 5-10 years of follow-up Plasma glucose (mmol/l) 15 10 5 0 0 30 60 90 120 150 Controls NOpGDM OpGDM Time (min) Plasma insulin levels in non obese and obese women with previous GDM, after 5-10 years of follow-up Plasma insulin (pmol/l) 800 Controls 600 400 200 0 0 30 60 90 120 150 NOpGDM OpGDM Time (min) Logistic regression analysis of factors related to the development of diabetes in women with previous GDM Factor Odds ratio 6.94 95% CI Fasting glucose at diagnosis 0-120 min glucose AUC at postpartum OGTT 0-60 min insulin AUC at diagnostic OGTT 1.83-26.24 3.15 1.08-9.23 5.26 1.13-22.50 Glucose tolerance at follow-up in women with previous GDM and healthy controls Status at follow-up Normal OGTT IGT Type 2 DM Type 1 DM GDM (n=139) 64.7 (90) 20.1 (28) 10.8 (15) 4.3 (6) Controls (n=27) 88.9 (24) 11.1 (3) --------------- Conclusions  J. Nerup said that Type 1 diabetes is the nightmare of geneticists. Paraphrasing his statement, we can say that GDM is the nightmare of epidemiologists. There is controversy about its definition, the best diagnostic method, diagnostic criteria, and the population to be screened. Conclusions (2)  Despite this confusion, the management of the condition has greatly improved, and the perinatal outcomes of offspring's of GDM mothers are comparable to those of non-diabetic women, except for macrosomia. Conclusions(3) There is an increasing body of evidence supporting the risk of developing diabetes mellitus (and particularly type 2 diabetes) among women with previous GDM  Among obese GDM women, even years after delivery, features of insulin resistance can be found 