Background Most analyses of excess mortality during the COVID-19 pandemic have employed aggregate data. Individual-level data from the largest integrated healthcare system in the US may enhance understanding of excess mortality. Methods We performed an observational cohort study following patients receiving care from the Department of Veterans Affairs (VA) between 1 March 2018 and 28 February 2022. We estimated excess mortality on an absolute scale (i.e. excess mortality rates, number of excess deaths) and a relative scale by measuring the hazard ratio (HR) for mortality comparing pandemic and pre-pandemic periods, overall and within demographic and clinical subgroups. Comorbidity burden and frailty were measured using the Charlson Comorbidity Index and Veterans Aging Cohort Study Index, respectively. Results Of 5 905 747 patients, the median age was 65.8 years and 91% were men. Overall, the excess mortality rate was 10.0 deaths/1000 person-years (PY), with a total of 103 164 excess deaths and pandemic HR of 1.25 (95% CI 1.25–1.26). Excess mortality rates were highest among the most frail patients (52.0/1000 PY) and those with the highest comorbidity burden (16.3/1000 PY). However, the largest relative mortality increases were observed among the least frail (HR 1.31, 95% CI 1.30–1.32) and those with the lowest comorbidity burden (HR 1.44, 95% CI 1.43–1.46). Conclusions Individual-level data offered crucial clinical and operational insights into US excess mortality patterns during the COVID-19 pandemic. Notable differences emerged among clinical risk groups, emphasizing the need for reporting excess mortality in both absolute and relative terms to inform resource allocation in future outbreaks.

中文翻译：

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COVID-19 大流行期间美国退伍军人的超额死亡率：一项个体层面的队列研究

背景 大多数对 COVID-19 大流行期间超额死亡率的分析都采用了汇总数据。来自美国最大的综合医疗保健系统的个人数据可能会增强对超额死亡率的了解。方法 我们对 2018 年 3 月 1 日至 2022 年 2 月 28 日期间接受退伍军人事务部 (VA) 护理的患者进行了一项观察性队列研究。我们估计了绝对规模的超额死亡率（即超额死亡率、超额死亡人数）和通过测量总体以及人口和临床亚组内的大流行和大流行前时期的死亡率风险比（HR）来确定相对规模。分别使用查尔森合并症指数和退伍军人老龄化队列研究指数来衡量合并症负担和虚弱程度。结果 5 905 747 名患者中，中位年龄为 65.8 岁，其中 91% 为男性。总体而言，超额死亡率为 10.0 人死亡/1000 人年 (PY)，总共有 103 164 人超额死亡，大流行 HR 为 1.25 (95% CI 1.25–1.26)。最虚弱的患者（52.0/1000 PY）和合并症负担最高的患者（16.3/1000 PY）的超额死亡率最高。然而，相对死亡率增幅最大的是体弱者（HR 1.31，95% CI 1.30-1.32）和合并症负担最低的人（HR 1.44，95% CI 1.43-1.46）。结论 个人层面的数据为了解 COVID-19 大流行期间美国超额死亡率模式提供了重要的临床和操作见解。临床风险群体之间出现了显着差异，强调需要报告绝对和相对的超额死亡率，以便为未来疫情爆发时的资源分配提供信息。