At the population level, there is limited empirical evidence on the characteristics of individuals who were hospitalized because of Covid-19, the role of hospitalization in mortality risk, and how both evolved over time. Through the analysis of surveillance data for 7 million people in Austria, Germany, and Italy, we investigate: (1) the demographic characteristics and outcomes of individuals hospitalized because of Covid-19; and (2) the role of demographic risk factors and healthcare utilization (as measured by hospitalization) for the individual probability of dying because of Covid-19, in both cases comparing the period February to June 2020 with July 2020 to February 2021. We find that the demographic profile of individuals who were hospitalized or died because of Covid-19 is the same in both periods, except for a younger age profile for hospitalizations in the second period. Mortality differentials across countries result from the interaction of demographic risk factors and hospitalization at the individual level.

在人口层面，关于因 Covid-19 住院的个人特征、住院在死亡风险中的作用以及两者如何随时间演变的经验证据有限。通过分析奥地利、德国和意大利 700 万人的监测数据，我们调查了：(1) 因 Covid-19 住院的个人的人口特征和结果；(2) 人口学风险因素和医疗保健利用率（以住院治疗衡量）对个人因 Covid-19 死亡的概率的影响，在这两种情况下都将 2020 年 2 月至 6 月与 2020 年 7 月至 2021 年 2 月期间进行比较。我们发现因 Covid-19 住院或死亡的个人的人口统计特征在这两个时期是相同的，除了第二阶段住院的年龄较小之外。各国之间的死亡率差异是人口风险因素与个人住院治疗相互作用的结果。