Critical evaluation of the diagnosis of Gestational Diabetes Mellitus (GDM)

1
Critical evaluation of the diagnosis of
Gestational Diabetes Mellitus (GDM)

• Simon Weitzman, MD, MPH

2
Critical evaluation of the diagnosis of
Gestational Diabetes Mellitus (GDM)

• Diagnostic methods and criteria
• Screening strategies
• Maternal and offspring outcomes

3
Critical evaluation of the diagnosis of
Gestational Diabetes Mellitus (GDM)

• Diagnostic methods and criteria
• Screening strategies
• Maternal and offspring outcomes

4
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

5
Diagnostic criteria for GDM

• Method Criteria (mg/dl)
• FPG 1 hr. 2 hr. 3 hr.
• WHO (75 gr) 140 - 200 -
• NDDG (100 gr) 105 190 165 145
• Coustan (100 gr) 95 180 155 140
• FPG Fasting plasma glucose

6
Critical evaluation of the diagnosis of
Gestational Diabetes Mellitus (GDM)

• Diagnostic methods and criteria
• Screening strategies
• Maternal and offspring outcomes

7
Screening strategies for GDM

• The approach
• One-step approach
• Two-step approach

8
The 50 gr. GCT (Cutoff gt186 mg/dl)

• Sensitivity 38.2
• Specificity 93.3

• Positive Predictive Value 78.6
• Negative Predictive Value 70.0

9
The 50 gr. GCT (Cutoff gt186mg/dl)

• Sensitivity 38.2
• Specificity 93.3

• Positive Predictive Value19.5
• Negative Predictive Value 97.2

10
Screening strategies for GDM

• The population
• Universal screening
• High risk groups screening

11
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 gt 40 of GDM

12
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

13
Critical evaluation of the diagnosis of
Gestational Diabetes Mellitus (GDM)

• Diagnostic methods and criteria
• Screening strategies
• Maternal and offspring outcomes

14
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

15
Maternal and offspring outcomes

• Characteristic Normal OGTT GDM
• LGA () 34
  38
• Gestational age (w) 39
  39.2
• Hospital days 3.7
  3.9
  

16
Perinatal characteristics of women with GDM,
according to risk factors

• Characteristic Risk Factors
  OR(95CI) Yes No
• Cesarean section () 38 35
  1.6 (0.7-3.7)
• Macrosomia () 33 17
  2.4 (0.9-6.7)
• Shoulder Dystocia () 7
  13 0.5 (0.1-2.1)
• Insulin therapy () 30
  28 1.1 (0.4-2.7)

17
Plasma glucose levels in non obese, and obese
women with previous GDM, after 5-10 years of
follow-up
18
Plasma insulin levels in non obese and obese
women with previous GDM, after 5-10 years of
follow-up
19
Logistic regression analysis of factors related
to the development of diabetes in women with
previous GDM
20
Glucose tolerance at follow-up in women with
previous GDM and healthy controls
21
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.

22
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.

23
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