Diabetes Testing Immediately Postpartum After Gestational Diabetes Mellitus

OBJECTIVE: Patient receipt of outpatient postpartum glucose testing after gestational diabetes mellitus (GDM) remains suboptimal. We conducted a randomized controlled trial (RCT) to determine whether the frequency of receiving a postpartum oral glucose tolerance test (OGTT) differed depending on whether the test was planned for the inpatient or outpatient setting. METHODS: DIP (Diabetes Testing Immediately Postpartum) was a pragmatic, nonblinded RCT. Participants were eligible if they received prenatal care and had a GDM diagnosis. After delivery, individuals were randomized in a 1:1 ratio to receive an OGTT either inpatient before delivery discharge (intervention) or outpatient within 12 weeks of birth (standard care). The primary outcome was completion of a fasting 2-hour 75-g OGTT by 12 weeks postpartum or less. Secondary outcomes included participant satisfaction per the adapted DTSQ (Diabetes Treatment Satisfaction Questionnaire) and diagnosis of prediabetes or type 2 diabetes. Based on an estimated baseline testing rate of 52% and a treatment effect of at least 50%, a sample size of 104 participants was required with 80% power and a two-sided α of 0.05. RESULTS: A total of 104 individuals with GDM were enrolled (52 intervention, 52 standard care). Demographics, unmet social needs, and clinical characteristics did not differ according to group assignment. Postpartum visit completion was more than 90% in both groups. The frequency of postpartum diabetes testing was significantly higher in the inpatient group compared with the outpatient group (92.3% vs 26.9%, relative risk 3.43 [95% CI, 2.18-5.40]), as was the median [IQR] score on the DTSQ (35.0 [31.0, 36.0] vs 28.0 [24.0, 32.0], P <.001). Prediabetes or type 2 diabetes was diagnosed among 50.0% in the inpatient group and 21.4% in the outpatient group ( P =.05). CONCLUSION: Diabetes testing before delivery discharge for individuals with GDM resulted in more than a threefold higher completion rate of postpartum glucose testing and greater patient satisfaction compared with outpatient testing. This RCT supports recent guidelines that encourage the option of inpatient postpartum diabetes testing before delivery discharge. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov , NCT05909046.