Background

Dementia and frailty often accompany one another in older age, requiring complex care and resources. Available projections provide little information on their joint impact on future health-care need from different segments of society and the associated costs. Using a newly developed microsimulation model, we forecast this situation in Japan as its population ages and decreases in size.

Methods

In this microsimulation modelling study, we built a model that simulates an individual's status transition across 11 chronic diseases (including diabetes, coronary heart disease, and stroke) as well as depression, functional status, and self-reported health, by age, sex, and educational strata (less than high school, high school, and college and higher), on the basis of nationally representative health surveys and existing cohort studies. Using the simulation results, we projected the prevalence of dementia and frailty, life expectancy with these conditions, and the economic cost for formal and informal care over the period 2016–43 in the population of Japan aged 60 years and older.

Findings

Between 2016 and 2043, life expectancy at age 65 years will increase from 23·7 years to 24·9 years in women and from 18·7 years to 19·9 years in men. Years spent with dementia will decrease from 4·7 to 3·9 years in women and 2·2 to 1·4 years in men. By contrast, years spent with frailty will increase from 3·7 to 4·0 years for women and 1·9 to 2·1 for men, and across all educational groups. By 2043, approximately 29% of women aged 75 years and older with a less than high school education are estimated to have both dementia and frailty, and so will require complex care. The expected need for health care and formal long-term care is anticipated to reach costs of US$125 billion for dementia and $97 billion for frailty per annum in 2043 for the country.

Interpretation

Japan's Government and policy makers should consider the potential social challenges in caring for a sizable population of older people with frailty and dementia, and a widening disparity in the burden of those conditions by sex and by educational status. The future burden of dementia and frailty should be countered not only by curative and preventive technology innovation, but also by social policies to mitigate the health gap.

Funding

Japan Society for the Promotion of Science, Hitachi – the University of Tokyo Laboratory for a sustainable society, and the National Institute of Ageing.

中文翻译：

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预测 2016 年至 2043 年日本衰弱和痴呆症的患病率以及护理的经济成本：微观模拟模型研究

背景

老年痴呆症和虚弱往往同时存在，需要复杂的护理和资源。现有的预测几乎没有提供关于它们对社会不同阶层未来医疗保健需求的共同影响以及相关成本的信息。使用新开发的微观模拟模型，我们预测了日本随着人口老龄化和人口规模减少而出现的这种情况。

方法

在这项微观模拟建模研究中，我们建立了一个模型，模拟个体在 11 种慢性疾病（包括糖尿病、冠心病和中风）以及抑郁症、功能状态和自我报告健康方面的状态转变，按年龄、性别、和教育阶层（低于高中、高中、大学及以上），基于全国代表性健康调查和现有队列研究。利用模拟结果，我们预测了 2016-43 年日本 60 岁及以上人口中痴呆和虚弱的患病率、这些疾病的预期寿命以及正规和非正规护理的经济成本。

发现

2016年至2043年间，女性65岁的预期寿命将从23·7岁增加到24·9岁，男性从18·7岁增加到19·9岁。女性患痴呆症的年限将从 4·7 年减少到 3·9 年，男性则从 2·2 年减少到 1·4 年。相比之下，所有教育群体的女性虚弱年限将从 3·7 年增加到 4·0 年，男性从 1·9 年增加到 2·1 年。到 2043 年，大约 29% 75 岁及以上、高中以下教育的女性预计患有痴呆症和虚弱，因此需要复杂的护理。预计到 2043 年，该国对医疗保健和正规长期护理的预期需求将达到每年 1,250 亿美元的痴呆症费用和 970 亿美元的体弱费用。

解释

日本政府和政策制定者应考虑到照顾大量体弱和痴呆症老年人所面临的潜在社会挑战，以及这些疾病在不同性别和受教育程度方面的负担差距日益扩大。痴呆症和虚弱的未来负担不仅应该通过治疗和预防技术创新来应对，还应该通过缩小健康差距的社会政策来应对。

资金

日本学术振兴会、日立、东京大学可持续社会实验室和国立老龄化研究所。