Introduction:
The aim of this study was to analyze the changes in COVID-19 case fatality rates (CFR) in time and to examine the link between CFR and country-specific indicators referring to quality of healthcare, population and epidemiology in different stages of the COVID-19 outbreak in 30 European countries (EU27 + Switzerland, Norway and United Kingdom).

Material and methods:
We distinguished three 70-day time phases of the outbreak: 17 March–25 May; 1 June–9 August; 15 August–23 October 2020. The applied COVID-19 dataset was based on data maintained by OurWorldInData.org retrieved in November 2020. Spearman’s rank correlation coefficient analysis was used to examine the link between CFR and country-specific indicators referring to population, epidemiology and quality of healthcare.

Results:
COVID-19 CFR in analyzed European countries declined from mid-March to end-October. CFR phase 1 was positively correlated with COVID-19 mortality, daily cumulative index (DCI), urbanization and proportion of the population aged > 80; CFR phase 2 was positively correlated with COVID-19 mortality and DCI; CFR phase 3 was positively correlated with COVID-19 mortality, median age, poverty, prevalence of obesity, smoking and cardiovascular disease and negatively correlated with Healthcare Access and Quality Index, Health Care Index and gross domestic product per capita.

Conclusions:
Results of our correlation analyses support the concept that the decline in CFR is real and, depending of the phase of the outbreak, different factors play a role. From the public health perspective, measures implemented to reduce the viral transmission, isolating the most vulnerable and improving the overall quality of the healthcare system are advisable.