The age-standardized incidence, mortality, and case fatality rates of COVID-19 among 79 countries: cross-sectional comparison and their correlation with associated factors.

Hong, Dongui; Lee, Sohyae; Choi, Yoon-Jung; Moon, Sungji; Jang, Yoonyoung; Cho, Yoon-Min; Lee, Hyojung; Min, Sukhong; Park, Hyeree; Hahn, Seokyung; Choi, Ji-Yeob; Shin, Aesun; Kang, Daehee

Objectives During the coronavirus disease 2019 (COVID-19) pandemic, crude incidence and mortality rates have been widely reported; however, age-standardized rates are more suitable for comparison. In this study, we estimated and compared the age-standardized incidence, mortality, and case fatality rates among countries and investigated the relationship between these rates and factors associated with healthcare resources: gross domestic product per capita, number of hospital beds per population, and number of doctors per population. Methods The incidence, mortality, and case fatality rates of 79 countries were age-standardized using the WHO standard population. The rates for persons 60 years or older were also calculated. The relationships among the rates were analysed using trend lines and coefficients of determination (R2). The Pearson's correlation coefficients between the rates and the healthcare resource-related factors were calculated. Results The countries with the highest age-standardized incidence, mortality, and case fatality rates were Czechia (14,253 cases/100,000), Mexico (182 deaths/100,000), and Mexico (6.7%), respectively. The R2 between the incidence and mortality rates was 0.8520 for all ages and 0.9452 for those 60 years or older. The healthcare resources-related factors were associated positively with incidence rates, and negatively with case fatality rates: the correlations were weaker among the elderly. Conclusion Compared to age-standardized rates, crude rates showed greater variation between countries. Medical resources may be important in preventing COVID-19-related deaths; however, considering the small variation in fatality among the elderly, prevention such as vaccination is more important especially for the elderly population to minimize the mortality rates in the elderly population.