One-Year Follow-Up of Medicare Advantage Enrollees with Type 2 Diabetes and an Initial Elevated HbA1c Value

Introduction: Blood glucose control is critical to slowing the onset of T2DM complications for individuals. National guidelines encourage clinicians and payers to ensure patient HbA1c lab results are less than 8.0%. Understanding the longitudinal patterns of HbA1c control among individuals with lab results over 8.0% is therefore an important undertaking. This study aims to characterize the proportion of individuals returning to HbA1c control within a one year period after an uncontrolled result.

Population and Study Design: Medicare Advantage (MA) patients with a large, national health and wellness company residing in Florida with a diagnosis of type 2 diabetes were included if they had an HbA1c lab value greater than or equal to 8.0% in 2016. Patients had at least one year of continuous coverage prior to the uncontrolled result and were followed until disenrollment, death, or a controlled HbA1c lab value, up to a maximum of one year. Cox regression stratified by initial HbA1c value (8.0-8.9%, 9.0-9.9%, 10.0-10.9%, 11.0-11.9%, 12.0%+) was used to assess the adjusted proportion of persons returning to control over the one year follow-up period. Confounders in the model included: demographic factors, supply of insulin, and comorbidities.

Results: The study cohort consisted of 28,026 persons who met the inclusion criteria (50.7% female, 57.4% white, mean age 71.9 years). Overall, 50.5% (95% CI: 50.0%, 51.1%) of persons achieved HbA1c control within the 1 year follow-up. Inability to return to control was driven by higher initial Hba1c [8.0-8.9% return rate: 61.6% (60.9%, 62.4%) vs. 9.0-9.9%: 39.4% (38.1%, 40.7%) vs. 12.0+%: 27.7% (25.1%, 30.2%)].

Implications: MA patients with HbA1c results greater than 9.0% experienced challenges resuming controlled status suggesting increased attention to this population may be warranted.