ABSTRACT
To determine whether immigrant background and socioeconomic status were associated with increased risk to develop severe Coronavirus disease 2019 (COVID-19) requiring mechanical ventilation at the intensive care unit and to study their effects on 90-day mortality. Nationwide case-control study with personal-level data from the Swedish Intensive Care register linked with socioeconomic data from Statistics Sweden and comorbidity data from the national patient register. For each case of COVID-19 treated with mechanical ventilation at the intensive care unit (outcome), 10 population controls were matched for age, sex and area of residence. Logistic and Cox regression were used to study the association between the exposure (immigrant background, income and educational level) and 90-day mortality. In total, 4 921 cases and 49 210 controls were matched. In the adjusted model, the risk of severe COVID-19 was highest in individuals born in Asia (Odds ratio [OR] = 2.44, 95% confidence interval [CI] = 2.20-2.69), South America (OR = 2.34, 95% CI = 1.82-2.98) and Africa (OR = 2.11, 95% CI = 1.76-2.50). Post-secondary education was associated with a lower risk of severe COVID-19 (OR = 0.75, CI = 0.69-0.82) as was the highest (vs. lowest) income quintile (OR = 0.87, CI = 0.77-0.97). In the fully adjusted Cox-regression analysis birth region of Africa (OR 1.38, CI = 1.03-1.86) and high income (OR 0.75, CI 0.63-0.89) were associated with 90-day mortality. Immigrant background, educational level and income were independently associated with acquiring severe COVID-19 with need for mechanical ventilation.