The Corona virus disease 2019 (COVID-19) pandemic is currently involving all parts of the world. Several risk factors for critical illness and death from the disease have been proposed. However, the observed associations between different comorbidities and chronic medications have not fully been related to the frequencies of the same comorbidities and chronic medications in age- and sex-matched controls from the general population. This is important since some of the proposed risk factors are very common in the aged who, by age alone, are more prone to a more severe course of the disease.

By combining several registries, we will compare, on several comorbidities such as hypertension and diabetes and several medications such as immunosuppressant drugs and Angiotensin Converting Enzyme (ACE)-inhibitors, the first 2000 cases of COVID-19 patients receiving critical care in Sweden to a set 8000 age- and sex-matched controls.

The COVID-19 pandemic is currently involving all parts of the world. Several risk factors for critical illness and death from the disease have been proposed. However, the observed associations between different comorbidities and chronic medications have not fully been related to the frequencies of the same comorbidities and chronic medications in age- and sex-matched controls from the general population. This is important since some of the proposed risk factors are very common in the aged who, by age alone, are more prone to a more severe course of the disease.

By combining several registries, we will compare, on several comorbidities such as hypertension and diabetes and several medications such as immunosuppressant drugs and ACE-inhibitors, the first 2000 cases of COVID-19 patients receiving critical care in Sweden to a set 8000 age- and sex-matched controls.

Data sources:

Registries of the Swedish board of Health and wellfare:

1. The patient registry containing information including diagnostic codes from all specialized Healthcare contacts in Sweden. Reporting i governed by law.
2. The Swedish Prescribed Drug Register to which all dispensations from pharmacies of prescribed drugs are reported.

Statistics Sweden is the agency responsible for the official population statistics of Sweden. They will draw our controls from the Registry of the total population.

The Swedish Intensive Care Registry (SIR) contains all intensive care episodes in Sweden. They have information on Intensive Care (ICU) admission, diagnoses, interventions and outcomes.

The study design is combined prospective ond retrospective. The data is prospectively collected to the registries but the study protocol is retrospectively designed.

Inclusion Criteria:

-Included in the SIR with COVID-19 any time until data acquisition

Exclusion Criteria:

-Age below 18 years.

The SIR is a registry to which all Swedish intensive care units are reporting all intensive care patients. The SIR has a specific part to wich all CIVID-19 related intensive care eposodes are reported. We will include, as cases, all patients, approximally 2000, who have at least one COVID-19 listing in the registry. Statistics Sweden will draw a random sample of age and sex matched controls, 4 per case, from all residents of Sweden, approximately 10 million.

Sharing of IPD is not allowed under the permission of the ethical review board.