Aim. To examine the impact of the lockdown caused by COVID-19 pandemic on both the glycemic control and the daily habits of a group of patients with type 1 diabetes mellitus (T1DM) using flash continuous glucose monitoring devices (Flash CGM). 

Methods. Retrospective analysis based on all the information gathered in virtual consultations from a cohort of 50 adult patients with T1DM with follow-up at our site. We compared their CGM metrics during lockdown with their own previous data before the pandemic occurred, as well as the potential psychological and therapeutic changes.

Results. We observed a reduction of the average glucose: 160.26 ± 22.55 mg/dl vs. 150 ± 20.96 mg/dl, p=0.0009, estimated HbA1c: 7.21 ± 0.78% vs. 6.83 ± 0.71%, p=000.5, glucose management indicator (GMI) 7.15 ± 0.57 % vs. 6.88 ± 0.49 %, p=0.0003, and glycemic variability (CV): 40.74 ± 6.66 vs. 36.43 ± 6.09 p<0.0001. Time in range showed an improvement: 57.46 ± 11.85% vs a 65.76 ± 12.09%, p<0.0001, without an increase in percentage of time in hypoglycaemia.

Conclusions: COVID-19 lockdown was associated with an improvement in glycemic control in patients with T1DM using CGM.

This retrospective study was conducted based on CGM metrics of patients with T1DM using a flash glucose monitoring system (FGM) FreeStyle Libre® Abbott, most of them in a multiple-dose of insulin injection therapy with a basal-bolus regime, carried out in the virtual consultations.

Data download from the devices through the Libreview platform was made, all corresponding to a 14-day period of time before and during lockdown, and the forms of both ambulatory glucose profiles were compared. No intermediate visits were conducted. All the recommendations gathered in the International Consensus of CGM were followed [⁵], analysing the following variables: percentage of device usage, average daily readings, average glucose, estimated glycosylated hemoglobin (HbA1c), glucose management indicator (GMI), coefficient of variation (CV), time in range (TIR), percentage of time below range (<70 mg/dl), number of low glucose events and total time (minutes) of registers below 70 mg/dl. Besides all this, virtual consultations were conducted following an established script with standardized questions to ensure that we collected the same data from all the subjects. These interviews collected information regarding follow-up during lockdown, emotional pattern, estimated variations of body weight, adjustments in the insulin doses, home daily physical activity, work situation, symptoms compatible with COVID-19 infection and specific diagnostic tests for the coronavirus. The standardized questions have been included in the supplementary table 1.