For women with gestational diabetes, conducting an oral glucose tolerance test (OGTT) during hospitalization for delivery might be useful to detect postpartum diabetes risk, as many women do not return for screening in the weeks after delivery, according to study results published in the American Journal of Obstetrics and Gynecology.
Researchers conducted this combined analysis of patient-level data from 6 clinical sites to compare the efficacy and usefulness of a 75-g OGTT administered during delivery hospitalization for diagnosis of type 2 diabetes (T2D) vs testing at 4 to 12 weeks postpartum.
Race/ethnicity, education, pre-pregnancy weight, weight at delivery, frequency of cesarean delivery, and frequency of breastfeeding varied significantly across centers, but mean age at enrollment did not.
In total, 319 women completed an OGTT during hospitalization. Nearly half (47.6%; n=167) were lost to follow-up before screening at 4 to 12 weeks postpartum. Of the women who had normal scores at the first test and completed a follow-up (n=73), none were found to have T2D. Overall, 12.6% of mothers transitioned from normal glucose to impaired fasting glucose or impaired glucose tolerance, or from impaired glucose regulation to T2D.
The OGTT during hospitalization had a sensitivity and specificity of 50% and 95.7%, respectively, as well as a negative predictive value of 98.1% and a positive predictive value of 30% for T2D vs any other result. Furthermore, a normal glucose result for OGTT during delivery hospitalization had a negative predictive value of 100% for having T2D at follow-up, with a specificity of 96.5%.
Limitations to this study included potential bias because of variations in patient inclusion criteria at each clinic. In addition, attrition bias may have affected the results, as the frequency of loss to follow-up was high.
“Based upon these results, it is unclear if immediate postpartum testing should replace traditional testing for all women with [gestational diabetes],” said the researchers. “In low resource centers or for populations with difficulty completing a traditional postpartum OGTT, a delivery hospitalization OGTT may be a reasonable alternative to evaluate for postpartum diabetes.”
Waters TP, Kim SY, Werner E, et al. Should women with gestational diabetes be screened at delivery hospitalization for type-2 diabetes? [published online July 24, 2019]. Am J Obstet Gynecol. doi:10.1016/j.ajog.2019.07.035