Impact of COVID-19 pandemic on glycemic control among outpatients with type 2 diabetes in Japan: A hospital-based survey from a country without lockdown

AIMS: Some studies have reported changes in glycemic control of patients with diabetes mellitus under lockdown. However, no previous study examined the impact of the pandemic on glycemic control in patients with diabetes in countries that did not introduce a lockdown such as Japan. This study aimed to assess changes in glycemic control during the pandemic in patients with type 2 diabetes treated at a Japanese clinic. METHODS: We conducted a historical cohort study, using electronic medical records of patients with type 2 diabetes who visited our clinic between January 2019 and August 2020. Differences in HbA1c values before and after the outbreak of COVID-19 were the primary outcome, examined using the linear mixed model. RESULTS: HbA1c values significantly increased from 7.45% to 7.53% after the state of emergency was introduced (n = 1,009). Furthermore, a deterioration in HbA1c values was observed in particular among women, patients aged ≥ 65 years, those with body mass index of ≥ 25 kg/m(2), and those that were not using insulin. CONCLUSIONS: Glycemic control deteriorated in patients with type 2 diabetes during the pandemic even in a country without a national lockdown.