Gestational Diabetes:Overview of Epidemiology and Risk for Future Glucose Intolerance Catherine Kim, M.D. M.P.H. Atlanta, December 8, 2006
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
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
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?
GDM Screening Recommendations • Low riskno screening; • Higher riskscreening • 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)
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
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 OGTTif (+), 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
GDM Screening Strategies (continued) • Center-specific strategies (Australia, Denmark) • Validated against that center’s particular birth outcomes (macrosomia) • Heterogeneity • Makes comparison between centers difficult
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
Age-Specific Prevalence by Birth Cohort Dabelea et al. Diabetes Care, 2005
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
Risk of recurrence of GDM MacNeill et al, Diabetes Care, 2001
Cumulative incidence, adjusted for diagnostic criteria Kim et al, Diabetes Care, 2002
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
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
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
Pap screening performed but not diabetes screening Smirinakis et al, Obstet Gynecol, 2005
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
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?
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
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
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
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
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
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
Table 1a. Percentages of recall of prenatal careDuring your GDM pregnancy, did any of your providers. . .
Table 1b. Percentages of recall of care after deliveryAfter your GDM pregnancy, did any of your providers. . .
Table 1c. Percentages of recall of specific items from the doctor’s office and health plan
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
Association between recall of advice and risk perception for diabetes, preventive behaviors, and postpartum DM screening
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
Next steps 1) Validation in written surveys 2) Associations persist after multivariable adjustment 3) Replication in more diverse populations