Factors associated with the difference between the incidence and case-fatality ratio of coronavirus disease 2019 by country

Coronavirus disease (COVID-19) has been spreading all over the world; however, its incidence and case-fatality ratio differ greatly between countries and between continents. We investigated factors associated with international variation in COVID-19 incidence and case-fatality ratio (CFR) across 107 northern hemisphere countries, using publicly available COVID-19 outcome data as of 14 September 2020. We included country-specific geographic, demographic, socio-economic features, global health security index (GHSI), healthcare capacity, and major health behavior indexes in multivariate models to explain this variation. Multiple linear regression highlighted that incidence was associated with ethnic region (p < 0.05), global health security index 4 (GHSI4) (beta coefficient [β] 0.50, 95% Confidence Interval [CI] 0.14–0.87), population density (β 0.35, 95% CI 0.10–0.60), and water safety level (β 0.51, 95% CI 0.19–0.84). The CFR was associated with ethnic region (p < 0.05), GHSI4 (β 0.53, 95% CI 0.14–0.92), proportion of population over 65 (β 0.71, 95% CI 0.19–1.24), international tourism receipt level (β − 0.23, 95% CI − 0.43 to − 0.03), and the number of physicians (β − 0.37, 95% CI − 0.69 to − 0.06). Ethnic region was the most influential factor for both COVID-19 incidence (partial R² = 0.545) and CFR (partial R² = 0.372), even after adjusting for various confounding factors.