Gestational Diabetes : Overview of Epidemiology and Risk for Future Glucose Intolerance

1. Gestational Diabetes:Overview of Epidemiology and Risk for Future Glucose Intolerance Catherine Kim, M.D. M.P.H. Atlanta, December 8, 2006

2. Objectives • Definition of gestational diabetes (GDM) • Current recommendations for screening for GDM • Trends in incidence • Risk for future glucose intolerance • Current recommendations for and performance of postpartum diabetes (DM) screening

3. Definition and Prevalence of GDM

4. Definition of GDM • Glucose intolerance first diagnosed during pregnancy ~10% pre-existing glucose intolerance, unrecognized ~90% glucose intolerance confined to pregnancy • Mechanism • Tissue sensitivities to insulin reduced 80% during normal pregnancy

5. Prevalence of GDM • Prevalence between 3-14% • 150,000-200,000 pregnancies each year • Higher rates among: • Latinas • Asian/Pacific Islanders • Native Americans/Alaskan Natives • African-Americans?

6. Recommendations for GDM Screening

7. GDM Screening Recommendations • Low riskno screening; • Higher riskscreening • Low risk: • Age < 25 years AND • Normal weight before pregnancy AND • No diabetes in 1° relatives AND • No history of glucose intolerance AND • No history of poor obstetric outcome AND • Racial/ethnic group with low prevalence of GDM • (No smoking, high physical activity, low glycemic index diet)

8. Controversy around GDM screening • Decades long debate about GDM screening • Argument against screening: more likely to undergo procedures • Australian Carbohydrate Intolerance Study in Pregnant Women, Crowther et al. (NEJM 2005). • Routine care vs. GDM treatment • Reduction in composite outcome of death, shoulder dystocia, bone fracture, nerve palsy in intervention women vs. routine care (1 vs. 4%). • Treated women had better mood and quality of life

9. What test should be used to screen? At 24-28 weeks gestation: • 100 gram oral glucose tolerance test (OGTT) • 4 blood draws • First blood draw fasting • 100 gram glucose drink • Blood draw every hour • 1979 NDDG criteria vs. Carpenter-Coustan • Drawbacks are discomfort, time, expense • 50 gram OGTTif (+), 100 gram OGTT • 50 gram drink, wait 1 hour, then a single blood draw • If failed (>140 mg/dl or >130 mg/dl), then standard 100 gram OGTT • Cost-effectiveness analysis (Nicholson W, Diabetes Care, 2005) • 75 gram OGTT (using IGT cut-offs) • 2 blood draws • First blood draw fasting • 75 gram drink

10. GDM Screening Strategies (continued) • Center-specific strategies (Australia, Denmark) • Validated against that center’s particular birth outcomes (macrosomia) • Heterogeneity • Makes comparison between centers difficult

11. Trends in Incidence

12. Incidence • Increased between 1990-2000 in all racial/ethnic groups • ? Leveling off after 2000 • ? Due to increased recognition of glucose intolerance before pregnancy • Greatest in Asians/Pacific Islanders • Greater with greater age

13. Age-Adjusted Incidence by Race/Ethnicity

14. Age-Specific Prevalence by Birth Cohort Dabelea et al. Diabetes Care, 2005

15. Risk for Glucose Intolerance

16. Risk for future glucose intolerance • Increased risk of another GDM pregnancy • Increased risk for future glucose intolerance in the fetus • Increased risk of type 2 DM in the mother

17. Risk of recurrence of GDM MacNeill et al, Diabetes Care, 2001

19. Cumulative incidence, adjusted for diagnostic criteria Kim et al, Diabetes Care, 2002

20. Predictors for Future Glucose Intolerance • Elevated fasting glucose, except in studies with measures of beta-cell function • 1- and 2-hour levels of glucose • Less consistent: • Maternal age • Body mass index, weight gain • Insulin use • Breastfeeding • Parity • Family history for diabetes

21. Postpartum Screening for Diabetes

22. Postpartum Screening Recommendations • 6 week postpartum: • 2 hour 75 gram OGTT • A screening test every 1-3 years thereafter • Determined by prevalence of diabetes in population Metzger et al, Diabetes Care, 1998

23. Low Postpartum Screening Rates • Women with GDM, 1997-2002, n=570 • Screening rates: • 23%: Recommended glucose 6 weeks p delivery • 38%: Any glucose 6 weeks post delivery • Women with GDM who had at least 1 return visit (n=447) • 35%: Recommended glucose 6 weeks p delivery • 42%: Any glucose Kim et al, Am J Public Health, 2006

24. Pap screening performed but not diabetes screening Smirinakis et al, Obstet Gynecol, 2005

25. Summary • Variable screening practices and definitions • GDM incidence increased in the 1990s • Women at risk for future glucose intolerance • Postpartum diabetes screening recommended at 6 weeks, 1 year, and every 3 years thereafter • Postpartum screening rates not optimal

26. Questions • What is evidence for diabetes prevention among women with GDM? • How can we enable prevention? • How can we improve women’s knowledge and screening rates? • What are the current practices at the patient and provider level? • What are the barriers to these improvements?

27. Women with a history of GDM: recall of quality of care Catherine Kim, MD MPH Laura N. McEwen, PhD John D. Piette, PhD Eve M. Kerr, MD MPH William H. Herman, MD MPH

28. Objectives • To determine patient recall of advice regarding GDM • To examine association with beliefs such as risk perception • To examine association with behaviors • To examine association with postpartum diabetes (DM) screening

29. Methods

30. Methods-Study Setting and Population • Current university health plan enrollees • Initial identification or diagnosis of GDM within 5 years of the survey AND • >1 outpatient visit or hospitalization during the 36 months before the survey • >1 of the following: • Hospital discharge diagnoses: ICD-9 code 648.8 OR • Outpatient diagnoses: Undelivered is 648.83 and delivered is 648.84

31. Exclusion criteria • Denied having had GDM • Currently pregnant with index pregnancy at time of survey • < 18 years of age • Not living in community • Could not give informed consent

32. Methods-Data collection and analysis • CATI/written surveys • Items developed through expert panel • Factor analysis of “quality” or recall items • Exploratory analysis • Scree/Kaiser-Guttman/Eigenvalues: 4-8 Factors • Cronbach α • Unadjusted or bivariate associations with outcomes of interest

33. Results

34. Results: Demographics • N=135 CATI, 85 written • Mean age: 36 ± 6 years • Education: < 1% had < high school • Race: 71% white, the remainder Asian/PI • Most recent diagnosis of GDM: ~2 years ago

35. Recall of advice and reminders

36. Table 1a. Percentages of recall of prenatal careDuring your GDM pregnancy, did any of your providers. . .

37. Table 1b. Percentages of recall of care after deliveryAfter your GDM pregnancy, did any of your providers. . .

38. Table 1c. Percentages of recall of specific items from the doctor’s office and health plan

39. Factor Analysis & Cronbach’s α • GDM-Specific Advice, α = 0.78 • GDM-Screening, α = 0.75 • General Lifestyle Advice, α = 0.59 • Doctor’s Office, α = 0.65 • Health Plan, α = 0.60

40. GDM-Advice Scale

41. GDM-Screening Scale

42. Association between recall of advice and risk perception for diabetes, preventive behaviors, and postpartum DM screening

43. Table 2. Risk Perception.

44. Association between risk perception and GDM-Specific Advice

45. Table 3. Percentages of physical activity and diet levels

46. Association between behaviors and GDM-Specific Advice

47. Association between walking and GDM-Specific Advice

48. Association between screening and recall of screening advice

49. Preliminary Conclusions • Recall of healthcare provider advice in a university-affiliated healthplan is high • Recall may be associated with preventive behaviors • Recall is associated with postpartum DM screening

50. Next steps 1) Validation in written surveys 2) Associations persist after multivariable adjustment 3) Replication in more diverse populations