Inclusion Criteria:  Patients with one of these three types of chronic diseases (Prevention Quality Indicators of the Agency for Healthcare Research and Quality): heart failure, diabetes, chronic obstructive pulmonary disease. All French adult patients suffering from the studied chronic diseases, covered by the Health Insurance and living in metropolitan France are included.  Exclusion Criteria:  Patients under 18 years of age or with incomplete or inconsistent data on the "Système National des Données de Santé", or with a symptomatic COVID-19 diagnosis.