Prospective transitions in hemoglobin A1c following gestational diabetes using multistate Markov models

We characterized the state-to-state transitions in postpartum hemoglobin A1c levels after gestational diabetes, including remaining in a state of normoglycemia or transitions between prediabetes or diabetes states of varying severity. We used data from the APPLE Cohort, a postpartum population-based cohort of individuals with gestational diabetes between 2009 and 2011, and linked A1c data with up to 9 years of follow-up (n = 34 171). We examined maternal sociodemographic and perinatal characteristics as predictors of transitions in A1c progression using Markov multistate models. In the first year postpartum following gestational diabetes, 45.1% of people had no diabetes, 43.1% had prediabetes, 4.6% had controlled diabetes, and 7.2% had uncontrolled diabetes. Roughly two-thirds of individuals remained in the same state in the next year. Black individuals were more likely to transition from prediabetes to uncontrolled diabetes (adjusted hazard ratio [aHR] = 2.32; 95% CI, 1.21-4.47) than White persons. Perinatal risk factors were associated with disease progression and a lower likelihood of improvement. For example, hypertensive disorders of pregnancy were associated with a stronger transition (aHR = 2.06; 95% CI, 1.39-3.05) from prediabetes to uncontrolled diabetes. We illustrate factors associated with adverse transitions in incremental A1c stages and describe patient profiles that may warrant enhanced postpartum monitoring.