Erika F Werner1, Phinarra Has2, Dwight Rouse2, Melissa A Clark2. 1. Alpert Medical School of Brown University; Women & Infants Hospital; School of Public Health Brown University. Electronic address: Erika_werner@brown.edu. 2. Alpert Medical School of Brown University; Women & Infants Hospital; School of Public Health Brown University.
Abstract
BACKGROUND: A majority of women in the United States with gestational diabetes mellitus (GDM) do not undergo the recommended 4-12 week post-partum glucose tolerance test (GTT). OBJECTIVE: To compare the diagnostic value of the 2-day postpartum GTT during the delivery hospitalization to the 4-12 week post-partum GTT in identifying impaired glucose metabolism 1 year post-partum STUDY DESIGN: Post-partum women who delivered at one hospital between January 2017 and July 2018 were offered enrollment in a prospective cohort if they had GDM diagnosed by Carpenter Coustan criteria or a 1-hour glucose challenge test >200 mg/dl, spoke English or Spanish, and planned to remain in-hospital until at least 2 days post-partum. Participating women underwent a 75-gram 2-hour GTTs on post-partum day 2 and were incentivized to have a 4-12 week GTT and measurement of glycosylated hemoglobin (HgbA1c) 1 year post-partum. Participants and providers were blinded to the 2-day post-partum results. The diagnostic value of an abnormal 2-day post-partum GTT (fasting > 100 mg/dl or 2 hour > 140 mg/dl) was compared to that of an abnormal 4-12 week GTT to identify HgbA1c > 5.7% (impaired glucose metabolism) and > 6.5% (diabetes) at 1 year post-partum. ROC curves were also compared at 2 days and 4-12 weeks post-partum. RESULTS: Of the 300 recruited women, 296 (99%) completed 2-day post-partum GTTs and 202 (68%) returned for 4-12 week GTT. At one-year post-partum, 203 (68%) had HgbA1c measured; 35% of whom had impaired glucose metabolism and 4% diabetes. The study population was diverse (46% non-Caucasian), 56% were obese (mean BMI 32 kg/m2), and 55% had received medication to control their glucose during pregnancy. There were no significant differences in the 2 day and 4-12 week post-partum GTT for predicting impaired glucose metabolism based on glycosylated hemoglobin >5.7% at one year post-partum: sensitivity (46% v. 36%), specificity (79% v. 84%), positive (52% v. 53%) and negative predictive value. (75% v. 72%), respectively. There was also no difference in the 2-day compared to the 4-12 week GTT for identifying diabetes at one year post-partum. Both the 2 day and 4-12 week GTTs had similar ROC curves for identifying impaired glucose metabolism and diabetes at 1 year post-partum. CONCLUSION: GTTs 2 days post-partum have similar diagnostic value as 4-12 weeks post-partum GTTs for predicting impaired glucose metabolism and diabetes 1 year post-partum and are associated with nearly 100% adherence to the test. Thus, changing the timing of the GTT should be considered.
BACKGROUND: A majority of women in the United States with gestational diabetes mellitus (GDM) do not undergo the recommended 4-12 week post-partum glucose tolerance test (GTT). OBJECTIVE: To compare the diagnostic value of the 2-day postpartum GTT during the delivery hospitalization to the 4-12 week post-partum GTT in identifying impaired glucose metabolism 1 year post-partum STUDY DESIGN: Post-partum women who delivered at one hospital between January 2017 and July 2018 were offered enrollment in a prospective cohort if they had GDM diagnosed by Carpenter Coustan criteria or a 1-hour glucose challenge test >200 mg/dl, spoke English or Spanish, and planned to remain in-hospital until at least 2 days post-partum. Participating women underwent a 75-gram 2-hour GTTs on post-partum day 2 and were incentivized to have a 4-12 week GTT and measurement of glycosylated hemoglobin (HgbA1c) 1 year post-partum. Participants and providers were blinded to the 2-day post-partum results. The diagnostic value of an abnormal 2-day post-partum GTT (fasting > 100 mg/dl or 2 hour > 140 mg/dl) was compared to that of an abnormal 4-12 week GTT to identify HgbA1c > 5.7% (impaired glucose metabolism) and > 6.5% (diabetes) at 1 year post-partum. ROC curves were also compared at 2 days and 4-12 weeks post-partum. RESULTS: Of the 300 recruited women, 296 (99%) completed 2-day post-partum GTTs and 202 (68%) returned for 4-12 week GTT. At one-year post-partum, 203 (68%) had HgbA1c measured; 35% of whom had impaired glucose metabolism and 4% diabetes. The study population was diverse (46% non-Caucasian), 56% were obese (mean BMI 32 kg/m2), and 55% had received medication to control their glucose during pregnancy. There were no significant differences in the 2 day and 4-12 week post-partum GTT for predicting impaired glucose metabolism based on glycosylated hemoglobin >5.7% at one year post-partum: sensitivity (46% v. 36%), specificity (79% v. 84%), positive (52% v. 53%) and negative predictive value. (75% v. 72%), respectively. There was also no difference in the 2-day compared to the 4-12 week GTT for identifying diabetes at one year post-partum. Both the 2 day and 4-12 week GTTs had similar ROC curves for identifying impaired glucose metabolism and diabetes at 1 year post-partum. CONCLUSION: GTTs 2 days post-partum have similar diagnostic value as 4-12 weeks post-partum GTTs for predicting impaired glucose metabolism and diabetes 1 year post-partum and are associated with nearly 100% adherence to the test. Thus, changing the timing of the GTT should be considered.
Authors: Maria I Rodriguez; Ann Martinez Acevedo; Jonas J Swartz; Aaron B Caughey; Amy Valent; K John McConnell Journal: JAMA Netw Open Date: 2022-04-01