Background

There are indications of improved glucose control in people with type 1 diabetes during the first wave of the COVID-19 pandemic. It is unknown whether and to what extent such improvement could be sustained during following COVID-19 waves. This study investigated, in people with type 1 diabetes, parameters of glycaemic control one year after the first wave of the COVID-19 pandemic and determined factors associated with improvement.

Methods

This was an observational cohort study in people with type 1 diabetes, aged ≥16 years. We compared HbA1c and flash glucose monitoring (FGM) glucometrics between the pre-lock-down period and after one-year of follow-up. Using regression analysis, we assessed baseline factors associated with HbA1c reduction of at least 5 mmol/mol.

Results

A total of 330 people with type 1 diabetes participated in the study. After one year of follow-up after the COVID-19 lockdowns, HbA1c decreased from 63.5±11.0 to 58.8±9.8 mmol/mol (p<0.001). % Time sensor is active increased from 77.6±29.7% to 87.2±22.6% and time in target range (% of time glucose 3.9–10.0 mmol/l) increased from 55.8±17.7% to 58.4±17.2%(p=0.013). Time below range (% time glucose ≤3.9 mmol/l) and % time glucose >13.9 mmol/l improved (from 5.0±5.0% to 3.7±3.8% and from 15.0±14.1% to 12.6±11.8% respectively; p<0.05). Glucose variability improved from 38.5±7.5% to 36.5±6.0% and duration of hypoglycaemic events decreased from 90 [69-118] minutes to 76 [59-91] minutes(p<0.001). In regression analysis, smoking, FGM use and higher HbA1c at baseline were associated with an HbA1c decrease of at least 5 mmol/mol.

Conclusion

This study shows improvement in a range of glycaemic outcomes in both HbA1c and FGM data, in individuals with type 1 diabetes over one-year follow period after start of the COVID-19 pandemic, particularly in smokers and participants using FGM and with higher HbA1c at baseline.