Factors associated with hospitalization, invasive mechanical ventilation treatment and death among all confirmed COVID-19 cases in Norway: Prospective cohort study

Aims: For everyone with a positive test for SARS-CoV-2 in Norway, we studied whether age, sex, comorbidity, continent of birth and nursing home residency were risk factors for hospitalization, invasive mechanical ventilation treatment and death. Methods: Data for everyone who had tested positive for SARS-CoV-2 in Norway by end of June 2020 (N = 8569) were linked at the individual level to hospitalization, receipt of invasive mechanical ventilation treatment and death measured to end of July 2020. Underlying comorbidity was proxied by hospital-based in- or outpatient treatment during the two months before the SARS-CoV-2 test. Multivariable generalized linear models were used to assess risk ratios (RRs). Results: Risk of hospitalization was particularly high for elderly (for those aged 90 and above: RR 9.5; 95% confidence interval (CI) 7.1-12.7; comparison group aged below 50), Norwegian residents born in Asia, Africa or Latin-America (RR 2.1; 95% CI 1.9-2.4; comparison group born in Norway), patients with underlying comorbidity (RR 1.6; 95% CI 1.4-1.8) and men (RR 1.3; 95% CI 1.2-1.5). Men and residents born in Africa, Asia and Latin-America were also at higher risk of receiving ventilation treatment and dying, but the mortality risk was especially high for the elderly (for those aged 90 and above: RR 607.9; 95% CI 145.5-2540.1; comparison group aged below 50) and residents in nursing homes (RR 4.2; 95% CI 3.1-5.7). Conclusions: High age was the most important predictor of severe disease and death if infected with SARS-CoV-2, and nursing home residents were at particularly high risk of death.

Automated summary

The study revealed that age, sex, comorbidity, continent of birth, and nursing home residency were risk factors for hospitalization, invasive mechanical ventilation treatment, and death in individuals with a positive test for SARS-CoV-2 in Norway. High age and nursing home residency were identified as particularly high-risk factors for death.