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Diabetes Mellitus During The Pandemic

Diabetes Mellitus During The Pandemic

The Study

The study aims to assess the effect of the pandemic on the blood glucose levels, dietary behaviors, and physical makeup of people with diabetes mellitus. It’s also done to pinpoint the components that lead to deteriorating blood glucose levels in individuals with diabetes mellitus.


In early 2020, the World Health Organization (WHO) declared a global pandemic. Since then, the virus has had a devastating impact on the world. By June 2022, over 536 million SARS-CoV-2 infections and 6 million deaths from the virus had been reported worldwide. 

The spread of the virus has been most severe in countries with limited resources and weak healthcare systems. The virus has spread rapidly in wealthy countries despite stringent social distancing measures and stay-at-home orders. Even in countries with robust healthcare systems, the virus has caused a disruption of daily life. Businesses have been forced to close, people have been laid off, and entire industries have been impacted. 

The virus has also had a significant psychological impact on people worldwide. The fear of catching the virus and the stress of trying to keep up with changing guidelines have caused anxiety and depression in many people. In response to the global pandemic, governments and healthcare organizations have worked together to develop treatments and vaccines for the virus.

People of all age groups can be infected. However, those over 65 years and those with comorbidities such as diabetes mellitus, chronic respiratory disease, and cardiovascular disease are at a higher risk of developing severe complications. 

Multiple systematic reviews and meta-analyses have found that individuals with diabetes mellitus have a two- to three-fold higher mortality risk from pandemic-related infections compared to those without the condition. A recent study has further shown that elevated levels of hemoglobin A1C (HbA1c) are associated with inflammation, hypercoagulability, low oxygen saturation, and a higher mortality rate. Consequently, people with diabetes mellitus should strive to maintain optimal glycemic control during the ongoing pandemic. 


A longitudinal observational study was conducted to investigate the influence of the pandemic on diabetes mellitus outpatients who visited the University of Tokyo hospital between April 2019 and March 2020 and were followed up from April 2020 to March 2021. 

The period from April 2019 to March 2020 was categorized as the pre-pandemic period and the period from April 2020 to March 2021 as the pandemic period. The values in each quarter (April-June, July-September, October-December, and January-March) were compared for each participant in order to determine the changes in HbA1c values, anthropometric variables, and nutritional intakes between the pre-pandemic and pandemic periods.

The first state of emergency for the pandemic in Japan was enforced from April 7 to May 25, 2020, and the second from January 8 to March 21, 2021. The study aimed to identify the determinants of worsening glycemic control. Inclusion criteria for participants included being over 18 years old and having undergone medical examinations, dietary surveys, and anthropometry at least once in the pre-pandemic and pandemic periods.

Statistical Analysis

To evaluate the descriptive statistics, the mean ± standard deviation (SD) was used for continuous variables and the number of cases (proportion) for categorical variables. Normality in continuous variables was tested using the Shapiro-Wilk test. 

Paired t-test was performed to compare the mean variation between the pre-pandemic and pandemic periods. For variables with non-normal distribution, Wilcoxon’s signed rank test was used. The participants were divided into two groups according to the mean variation of the HbA1c in the pre-pandemic and pandemic period (0.07%) – Worsen group, with an increase of >0.07% and Steady group, with a decrease or up to 0.07%. 

Student’s t-test and Mann-Whitney U-test were used to compare the groups for continuous variables and the chi-square test for categorical variables. Logistic regression analysis was then used to explore the factors related to the increase in HbA1c. A multivariate logistic regression analysis was completed to control for age and sex. Statistical significance was set at P < 0.05 and SPSS version 28.0 (IBM Corp., NY, USA) was used for all analyses.

In order to be part of the study, individuals had to have diabetes mellitus and have received medical exams, dietary surveys, and anthropometric assessments prior to and following the pandemic. 

Those who were 18 and under, pregnant, had undergone metabolic surgery, had recently been diagnosed with diabetes, followed a special diet, or had experienced diabetic ketoacidosis or hyperosmolar hyperglycemic syndrome during the study period were excluded. This study was reviewed and approved by the Research Ethics Committee at the University of Tokyo Hospital (2021068NI) in compliance with the Declaration of Helsinki while maintaining patient confidentiality.

In this study, a total of 408 individuals participated, including 239 males (58.6%) and 169 females (41.4%), with an average age of 60.5–12.9 years. The majority of them had type 2 diabetes mellitus (96.8%). 18.4% of the participants were taking insulin, 44.4% were taking biguanides, and 44.9% were taking DPP-4 inhibitors.


The annual mean HbA1c was significantly higher in the pandemic period (the HbA1c increased from 7.12–0.90% to 7.19–1.01%, P=0.010).

No changes in annual mean cholesterol or triglycerides were observed.

The annual mean systolic blood pressure was significantly higher in the pandemic period, with the annual mean diastolic blood pressure remaining unchanged.

No significant change in patient BMI was observed.

The average percent fat mass values were statistically higher during the pandemic period.

Final Thoughts

Since the first confirmed pandemic case was reported in China in December 2019, the pandemic has had wide-ranging consequences around the world, necessitating frequent lockdowns and other safety measures in many countries. 

This research project looks at how the pandemic has affected the glycemic control, dietary practices, and weight of people with diabetes in Japan, comparing the changes during two periods of emergency declaration in 2020 to the metrics from the same time frames in 2019. 

In order to account for seasonal and emergency duration effects, both years were divided into quarters and analyzed in-depth. To the best of our knowledge, this is the first longitudinal study to look into the impacts of the pandemic on diabetes patients.

This research revealed a major jump in the HbA1c levels of individuals with diabetes mellitus during the pandemic. The relative values of body weight, fat and muscular phosphorus were selected as independent contributors to elevated HbA1c levels, after considering matters like age and gender. 

Since there weren’t any considerable distinctions between the dietary intakes, the changes in the physiologic parameters such as body fat and muscle mass during the pandemic period could have been attributed to decreased physical activity. 

Studies have additionally pointed to a decrease in the daily step count and physical activity in the lower limbs, such as walking and running, during the pandemic. This study observed a decrease in the proportion of muscle mass in the lower body and could thus imply that people with diabetes mellitus who stayed at home had more limited access to aerobic exercise such as walking, cycling, and running. In the “new normal”, sustaining physical activity is essential to enhance the diabetes control of individuals with diabetes mellitus.

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