Trends and disparities in glycemic control and severe hyperglycemia in U.S. adults with diabetes mellitus before and during COVID-19 pandemic

BACKGROUND: The COVID-19 pandemic disrupted healthcare delivery and individual behaviors in individuals with diabetes. Limited data exist on glycemic control during this period. This study aimed to evaluate trends in glycemic control and severe hyperglycemia among U.S. adults with diagnosed diabetes before and during the COVID-19 pandemic. METHODS: We conducted a retrospective cohort analysis of data from the National Health and Nutrition Examination Survey (NHANES) between pre-pandemic (January 2017-March 2020) and pandemic (August 2021-August 2023) periods. Glycemic control (HbA1c < 7%) and severe hyperglycemia (HbA1c > 10%) were assessed overall and by age, race/ethnicity, and socioeconomic status using logistic regression. RESULTS: Among 2528 adults with diabetes, glycemic control remained unchanged between pre- and during the pandemic (59.7% vs. 56.1%, p = 0.29), but severe hyperglycemia increased significantly (5.6% to 8.5%, p = 0.03). Female participants were more likely to achieve glycemic control (adjusted OR [aOR], 1.40; 95% CI, 1.11-1.75), and those with more than high school education had higher glycemic control (aOR, 1.33; 95% CI, 1.06-1.67) and lower severe hyperglycemia (aOR, 0.51; 95% CI, 0.29-0.89). Severe hyperglycemia was least prevalent in adults aged 65 years or older (aOR, 0.27; 95% CI, 0.15-0.50) but more common among Hispanic/Mexican American (aOR, 2.62; 95% CI, 1.53-4.50) and Non-Hispanic Black adults (aOR, 2.80; 95% CI, 1.62-4.84). CONCLUSION: While glycemic control remained stable, severe hyperglycemia increased during the COVID-19 pandemic, particularly among Hispanic/Mexican American and Non-Hispanic Black adults. Higher education and older age were associated with better outcomes, emphasizing the need for targeted interventions to address disparities and prevent hyperglycemia.