Background: GDM is a strong risk factor for early development of diabetes. Yet, adherence to protocols for testing at postpartum is usually low. We investigated the main predictors of diabetes up to two years post-partum among women with recent GDM participating in the LINDA-Brasil cohort.
Methods: We recruited potential participants with GDM for an ongoing clinical trial of postpartum diabetes prevention, LINDA-Brasil. We ascertained diabetes by OGTT. We estimated relative risks and 95% CIs, and area under the ROC curve (AUC) for diabetes postpartum through logistic regression.
Results: We recruited 27women with GDM, of whom 1482 (55%) underwent OGTT testing postpartum. Among these, mean (SD) pre-pregnancy BMI was 30.2 (6.4) kg/m2 and mean age, 32.0 (6.3) years; 316 (21.3%) used insulin during pregnancy, an additional 314 (21.2%) oral hypoglycemic agents (OHAs). During follow-up, 163 (11%) developed diabetes. Use of insulin during pregnancy predicted a six-fold higher crude risk of developing diabetes postpartum (RR 6.7; 95% CI 4.7-9.4) and of OHAs, a two-fold risk (RR=2.0; 95% CI 1.4-2.9). The inclusion of just these two variables yielded an AUC of 0.754; adding fasting and 2h plasma glucose at the diagnosis of GDM increased it to 0.810; further addition of age and pre-pregnancy BMI increased it minimally (0.813), and age was not statistically significant. Most incident cases used insulin (59%) or OHAs alone (20%) during pregnancy, thus, 79% of all cases (sensitivity) could be identified as being at high risk just by this information. Stated as post-test probabilties, 20% of those using antidiabetic medication during pregnancy but only 4% of those not using medication developed diabetes.
Conclusions: Simple clinical or administrative information can be effectively used to prioritize screening and counselling for diabetes prevention in the initial years following pregnancy complicated by GDM.
C.D. Castilhos: None. R. Ladwig: None. M. Drehmer: None. B.B. Duncan: Research Support; Self; Eli Lilly and Company. Research Support; Spouse/Partner; Eli Lilly and Company. C. Facanha: None. M.I. Schmidt: Research Support; Self; Eli Lilly and Company. Research Support; Spouse/Partner; Eli Lilly and Company.