Effects of Two COVID-19 Lockdowns on HbA1c Levels in Patients with Type 1 Diabetes and Associations with Digital Treatment, Health Literacy, and Diabetes Self-Management: A Multicenter, Observational Cohort Study Over 3 Years

Abstract

Introduction: Short-term studies reported improved glycemic control and a decrease in eHbA1c (estimated hemoglobin A1c) in patients with type 1 diabetes during COVID-19 lockdown, but long-term changes are unknown. Therefore, the main objectives are to (1) analyze whether laboratory-measured HbA1c changed during and after two lockdowns and (2) investigate potential variables influencing HbA1c change.

Methods: In this cohort study, 291 adults with type 1 diabetes were followed over 3 years including the prepandemic phase and two lockdowns. The data from medical records and validated questionnaires assessing health literacy (HLS-EU-Q16), diabetes self-management (DSMQ-R27), general self-efficacy (GSE), and social support (F-SOZU-K14) were used to analyze associations with HbA1c levels (N = 2370) by performing multivariable linear regressions.

Results: The median age was 54 (38-63) years and 159 (54.6%) were male. All phases of the COVID-19 pandemic were associated with a significant increase in laboratory-measured HbA1c levels in percent (e.g., during first lockdown β = 0.23, 95% confidence interval (CI) 0.07-0.39, p = 0.005; during the second lockdown, β = 0.27, 95% CI 0.15-0.38, p < 0.001). HbA1c change during lockdowns was significantly affected by the number of checkups (β = -0.03, 95% CI -0.05 to -0.01, p = 0.010), the value of HbA1c at previous observation (β = 0.33, 95% CI 0.29-0.36, p < 0.001), educational level (secondary versus tertiary: β = 0.22, 95% CI 0.06-0.38, p = 0.008; primary versus tertiary: β = 0.31, 95% CI 0.10-0.52, p = 0.004), health literacy score (for each point: β = -0.03, 95% CI -0.05 to - 0.002, p = 0.034), and diabetes self-management score (for each point: β = -0.03, 95% CI -0.04 to -0.02, p < 0.001). The use of continuous glucose monitoring or insulin pump had no effect on HbA1c change.

Conclusions: Lockdowns can lead to worsening glycemic control in patients with type 1 diabetes. Particularly patients with few check-ups, poor blood glucose values, deficits in diabetes self-management, low health literacy, and a low level of education seem to be at greater risk of worsening glycemic control during lockdowns and, therefore, require special medical care, e.g., through telemedicine.

Trial registration: ClinicalTrials.gov identifier, NCT04821921.

Keywords: COVID-19; HbA1c; Health literacy; Type 1 diabetes.