Glycaemic control during the lockdown for COVID-19 in adults with type 1 diabetes: A meta-analysis of observational studies

Aims: To assess the effects of lockdown due to COVID-19 pandemic on glucose metrics, measured by glucose monitoring systems, in adult individuals with type 1 diabetes. Methods: We conducted a systematic literature search for English language articles from MEDLINE, Scopus and Web of Science up to February 28, 2021, using “diabetes”, “lockdown”, and “glucose” as key search terms. Time in range (TIR) was the main outcome; other metrics were time above range (TAR), time below range (TBR), mean blood glucose (MBG) and its variability (%CV), estimated HbA1c (eA1c) or glucose management indicator (GMI). Results: Seventeen studies for a total of 3,441 individuals with type 1 diabetes were included in the analysis. In the lockdown period, TIR 70–180 mg/dl increased by 3.05% (95% CI 1.67–4.43%; p < 0.0001) while TAR (>180 mg/dL and > 250 mg/dL) declined by 3.39% (−5.14 to −1.63%) and 1.96% (−2.51 to −1.42%), respectively (p < 0.0001 for both). Both TBR < 70 and <54 mg/dL remained unchanged. MBG slightly decreased by 5.40 mg/dL (−7.29 to −3.51 mg/dL; p < 0.0001) along with a reduction in %CV. Pooled eA1c and GMI decreased by 0.18% (−0.24 to −0.11%; p < 0.0001) and a similar reduction was observed when GMI alone was considered (0.15%, −0.23 to −0.07%; p < 0.0001). Sensor use was only slightly but not significantly reduced during lockdown. Conclusions: This meta-analysis shows that well-controlled people with type 1 diabetes on both MDI and CSII with continuous or flash glucose monitoring did not experience a deterioration in glucose control throughout the COVID-19 lockdown, showing a modest, though statistically significant improvement in many glucose control parameters.