Improvement in A1c Levels in Early Adulthood in the T1D Exchange: Impact of Racial, Socioeconomic, and Clinical Factors

CONTEXT: Glycemic control in adolescents with type 1 diabetes is poor; yet, it typically improves during early adulthood. Factors related to improvement of glycemic control are unclear. OBJECTIVE: This work examines how demographic and clinical variables may affect trajectories of glycemic control over time. METHODS: This retrospective, observational study comprised 1775 participants ages 18 to 30 years at enrollment in the T1D Exchange clinic registry. Latent class trajectory modeling was used to determine subgroups following a similar glycated hemoglobin A1c (HbA1c) trajectory over time. RESULTS: Five distinct trajectories of HbA1c classes were identified: "low-decline" and "moderate-decline" groups had low or moderate HbA1c with a gradual decline, the "high-stable" group had high HbA1c and remained stable, and the "very high-rapid decline" and "very high-slow decline" groups had very high HbA1c with rapid or gradual decline. Compared with the "high-stable" group, the "low-decline" and "moderate-decline" groups were more likely to be male (P = .009), White non-Hispanic (P = .02), nonsmokers (P < .001), check self-monitoring blood glucose (SMBG) more frequently (P < .001), and have higher education (P < .001), lower body mass index (P = .02), and lower daily insulin dose (P < .001). Compared with the "very high-rapid decline" and "very high-slow decline" groups, the "low-decline" and "moderate-decline" groups were more likely to be male (P = .02), have higher education (P < .001), use insulin pumps (P = .01), be nonsmokers (P < .001), and have a higher number of SMBG checks per day at enrollment (P < .001). CONCLUSION: We determined 5 distinct patterns of glycemic control from early adulthood into adulthood. Further evaluation into the modifiable factors associated with a declining HbA1c trajectory would aid in the development of targeted interventions.