Diabetes mellitus is a chronic disease characterized by the inability of the body to maintain normoglycemia. Treatment of diabetes relies mostly on diabetes self-management, requiring a large investment of time and energy on a daily basis. Psychological wellbeing, behavioral patterns and social context play a major role in diabetes self-management and glycemic control. Social isolation behavior (self-quarantining) may impact glycemic control by influencing daily routines, therapy adherence, physical activity, and self-measurement and eating behaviors. Therefore, a period of nationwide self-quarantine, such as during the lockdown issued during the COVID-19 outbreak in the Netherlands, may have a large effect on glycemic control in patients with diabetes.

In this observational cross sectional study, we aim to assess the impact of long-term self-quarantine on glycemic control, diabetes self-management and distress in patients with type 1 and type 2 diabetes mellitus.

A specific subgroup of patients with T1D are those with complicated diabetes who have received a pancreas or islet transplantation and use immunosuppression, having multiple risk factors for severe COVID-19. The impact of lockdown strategies on mental and physical health is expectedly even greater in patients at even higher risk for severe COVID-19. We therefore additionally investigated differences in behavioral, mental and physical implications of a nationwide lockdown on patients with type 1 diabetes with and without islet or pancreas transplantation.

Measurements will be performed during the lockdown period. Patients will be asked to perform a fingerprick HbA1c measurement once, sent back to the LUMC by mail. Data from continuous or flash glucose monitoring devices will be collected according to standard clinical practice. Furthermore, patients will be asked to fill out an online questionnaire once on diabetes self-management behavior, well-being and distress, along with questions about health status, level of education, medication use, employment, social situation and the impact of self-quarantine on daily routines. In this questionnaire, we ask patients to compare certain aspects of their life (e.g. anxiety, stress, weight, physical activity, glycemic control) at the time of the lockdown to before the lockdown. Data on demographics, type of diabetes, weight, BMI and HbA1c prior to the COVID-19 outbreak will be derived from the patient's electronic health file.

Inclusion Criteria:

• Age ≥ 18 years
• Diagnosed with type 1 or type 2 diabetes
• Ability to perform fingerpricks
• Sufficient comprehension of the Dutch language
• Ability to fill out online questionnaires

Exclusion Criteria:

• Pregnancy
• Newly diagnosed malignancy, with the exclusion of non-melanoma skin cancer, in the previous 6 months
• Chemotherapy or immunotherapy for malignancy
• Admission to hospital or rehabilitation center

Patients with type 1 diabetes (with and without islet or pancreas transplantation) and type 2 diabetes, recruited from the diabetes outpatient clinic of the LUMC.