In this study we cross-reference several nationwide high-quality Swedish registers inorder to study risk factors for severe Covid-19 outcomes.
In this nationwide, case-control study we cross-reference several detailed, high-quality
Swedish registers in order to study risk factors associated with severe Covid-19 as well
as different disease outcomes, with a focus on cardiovascular disease, chronic kidney
disease, different treatments and socioeconomic factors. Cases are identified through the
Swedish intensive care register (SIR) and controls through the Swedish population
register (RTB). Further information on the study participants is gathered by linkage to
registers on: prescribed drugs; history of in- and outpatient care; income, education and
migration. Follow-up data such as future hospitalization and mortality will be gathered
prospectively.
Other: Hypertension
Exposure : Any registered diagnosis of I10 within 15 years or a registered pick-up of a
prescription of antihypertensive treatment (ATC C02CA, C02DB02, C03, C07, C08, C09)
within one year before index date in the Swedish prescribed drug register (exluding those
with a registered diagnosis of other indications for betablocker (heart failure, atrial
fibrillation) or ACE-inhibitor, ARB(heart failure) ) Exposures will be compared between
cases and controls and between cases with different outcomes and controls
Other: Diabetes type 2
Exposure: Any registered diagnosis of E11 within 15 years or a registered pick-up of a
prescription with any antidiabetic treatment (ATC A10) within one year before index date
in the Swedish prescribed drug register.
Exposures will be compared between cases and controls and between cases with different
outcomes and controls
Other: Obesity
Exposure: Diagnosis ICD E66 within 15 years before index date Exposures will be compared
between cases and controls and between cases with different outcomes and controls
Drug: Antihypertensive Agents
Pick up of a prescription of C02CA, C02DB02, C03, C07, C08, C09 registered in the Swedish
prescribed drug register within 6 month before index date.
Exposures will be studied separately for each antihypertensive class and compared between
cases and controls and between cases with different outcomes and controls
Drug: Statins (Cardiovascular Agents)
Pick up of a prescription of C10AA registered in the Swedish prescribed drug register
within 6 month before index date.
Other: Chronic kidney disease
Exposure: Diagnosis ICD N18 within 15 years before index date Exposures will be compared
between cases and controls and between cases with different outcomes (mechanical
ventilation, continuous renal replacement therapy mortality) and controls. Exposures will
thereafter be compared in subgroups by BMI at ICU-admission and in subgroups matched by
history of type 2 diabetes.
Inclusion Criteria:
- Cases: Admitted to intensive care unit in Sweden and registered admission in the
Swedish intensive care register (SIR) with a main diagnosis of Covid-19 confirmed by
laboratory testing (ICD10: U07.1). (cases)
- Control subjects matched for age, gender,residency: For each case 10 controls
matched for age, gender and district of residence will be identified by Statistics
Sweden (SCB) in the Swedish population register (RTB).
- Control subjects matched for age and gender: For each case 5 controls matched for
age and gender will be identified by by Statistics Sweden (SCB) in the Swedish
population register (RTB).
Exclusion Criteria:
- No valid Swedish personal identity number (PIN)
Södersjukhuset
Stockholm, Sweden