美国老年人的健康与长寿：证据与启示

中文摘要

老年人口预期寿命的延长，是社会保障和医疗保险面临的一个众所周知的财政压力来源——但死亡率和发病率的下降究竟如何影响这两个项目的相对财务状况？利用近三十年（1992—2019年）的医疗保险当前受益人调查（Medicare Current Beneficiary Survey）数据，我们估计，这些人口结构变化使预期终身社会保障支出的增幅是预期终身医疗保险支出增幅的两倍以上：分别为14%和6%。老年人终身医疗保健支出的增长慢于年金支出的增长，这反映了预期寿命延长的两个特征：新增的2.4年剩余预期寿命完全是健康的——不存在身体或认知方面的限制；同时，预计处于严重健康受限状态的时间减少了约30%，从而降低了预期终身护理院和居家医疗服务的使用量。随后，我们构建了一个风格化的生命周期模型，模型中风险厌恶型退休者面临随机的死亡率和健康状况，以阐明影响在医疗保险与社会保障之间进行固定数额公共资金最优配置的关键力量。

Abstract

Rising elderly life expectancy is a well-known source of fiscal pressure on Social Security and Medicare – but how have declining mortality and morbidity affected the two programs’ relative finances? Using nearly three decades of Medicare Current Beneficiary Survey data (1992-2019), we estimate that these demographic changes raised expected lifetime Social Security spending by over twice as much as expected lifetime Medicare spending: 14% compared to 6%. The slower growth of elderly lifetime health care spending than annuity spending reflects two features of how longevity has increased: the additional 2.4 years of remaining life expectancy were entirely healthy – free of physical or cognitive limitations – while the expected amount of time spent with severe health limitations fell by about 30%, reducing expected lifetime nursing-home and home-health use. We then write down a stylized life-cycle model of a risk-averse retiree facing stochastic mortality and health to illuminate the key forces that affect the optimal allocation of a fixed amount of public funds across Medicare and Social Security.