Gaps Remain for Achieving HbA1c Targets for People with Type 1 or Type 2 Diabetes Using Insulin: Results from NHANES 2009–2020

INTRODUCTION: Glycated hemoglobin A1c (HbA1c) is an important measure to assess glycemic control and predict diabetes complications. However, there is limited information on trends in HbA1c among people with diabetes (PwDs) who use insulin. The aim of this study was to describe trends in HbA1c among PwDs who use insulin by diabetes type and insulin regimen. METHODS: A retrospective analysis was conducted using data from the National Health and Nutrition Examination Survey (NHANES, 2009–2020). PwDs were classified into three cohorts: type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus using mealtime insulin (T2DM-MTI), and type 2 diabetes mellitus (T2DM) using basal-only insulin (T2DM basal-only). Trends in HbA1c over time were assessed using regression analysis after adjusting for age, gender, and race/ethnicity. RESULTS: Mean HbA1c values aggregated over 2009–2020 were 8.0% (T1DM), 8.6% (T2DM-MTI), and 8.6% (T2DM basal-only). The American Diabetes Association-recommended target of HbA1c of < 7% was achieved by 25.2% of people in the T1DM and T2DM-MTI groups each and by 12.3% of people in the T2DM basal-only group. Over time, an upward trend was observed in the percentage of people achieving HbA1c < 7% in the T2DM basal-only group. The percentage of PwDs achieving individualized HbA1c targets was 27.0%, 12.4%, and 16.1% for the T1DM, T2DM-MTI, and T2DM basal-only groups, respectively. CONCLUSIONS: Our study using NHANES data suggests that approximately 25% of PwDs achieve glycemic targets. This study highlights the need for improved therapies to better manage glycemic targets in PwDs.