Comparison of Japanese Centenarians' and Noncentenarians' Medical Expenditures in the Last Year of Life

IMPORTANCE

Although research has shown that centenarians tend to experience shorter periods of serious illness compared with other age groups, few studies have focused on the medical expenditures of centenarians as a potential indicator of the scale of medical resources used in their last year of life.

OBJECTIVE

To compare Japanese centenarians' and noncentenarians' monthly medical expenditures during the year before death according to age and sex.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used linked national health and long-term care insurance data collected from April 2013 to March 2018 in Nara Prefecture, Japan, for residents aged 75 years or older who were insured under the Medical Care System for older adults and died between April 2014 and March 2018. Data were analyzed from April 2013 to March 2018.

EXPOSURES

Age of 100 years or older (centenarians) vs 75 to 99 years (noncentenarians).

MAIN OUTCOMES AND MEASURES

The numbers of unique inpatients and outpatients and medical expenditures related to decedents' hospitalization and outpatient care were extracted and analyzed based on sex and age group. The Jonckheere-Terpstra test was used to identify trends in unadjusted medical expenditures by age group, and generalized estimating equations were used to estimate monthly median expenditures by age group with adjustment for comorbidity burden and functional status.

RESULTS

Of 34 317 patients aged 75 to 109 years (16 202 men [47.2%] and 18 115 women [52.8%]) who died between April 2014 and March 2018, 872 (2.5%) were aged 100 to 104 years (131 men [15.0%] and 741 women [85.0%]) and 78 (0.2%) were aged 105 to 109 years (fewer than 10 were men). The analysis of unadjusted medical expenditures in the last year of life showed a significant trend of lower expenditures for the older age groups; the median adjusted total expenditures during the 30 days before death by age group were $6784 (IQR, $4884-$9703) for ages 75 to 79 years, $5894 (IQR, $4292-$8536) for 80 to 84 years, $5069 (IQR, $3676-$7150) for 85 to 89 years, $4205 (IQR, $3085-$5914) for 90 to 94 years, $3522 (IQR, $2626-$4861) for 95 to 99 years, $2898 (IQR, $2241-$3835) for 100 to 104 years, and $2626 (IQR, $1938-$3527) for 105 to 109 years. The proportion of inpatients among all patients in the year before death also decreased with increasing age: 4311 of all 4551 patients aged 75 to 79 years (94.7%); 43 of all 78 patients aged 105 to 109 years (55.1%); 2831 of 2956 men aged 75 to 79 years (95.8%); 50.0% of men aged 105 to 109 years (the number is not reported owing to the small sample size); 1480 of 1595 women aged 75 to 79 years (92.8%); and 55.7% of women aged 105 to 109 years (the number of women is not reported to prevent back-calculation of the number of men). Specifically, 274 of 872 patients aged 100 to 104 years (31.4%) and 35 of 78 patients aged 105 to 109 years (44.9%) had not been admitted to a hospital in the year before death.

CONCLUSIONS AND RELEVANCE

This cohort study found that medical expenditures in the last year of life tended to be lower for centenarians than for noncentenarians aged 75 years or older in Japan. The proportion of inpatients also decreased with increasing age. These findings may inform future health care services coverage and policies for centenarians.

Human mortality at extreme age

We use a combination of extreme value statistics, survival analysis and computer-intensive methods to analyse the mortality of Italian and French semi-supercentenarians. After accounting for the effects of the sampling frame, extreme-value modelling leads to the conclusion that constant force of mortality beyond 108 years describes the data well and there is no evidence of differences between countries and cohorts. These findings are consistent with use of a Gompertz model and with previous analysis of the International Database on Longevity and suggest that any physical upper bound for the human lifespan is so large that it is unlikely to be approached. Power calculations make it implausible that there is an upper bound below 130 years. There is no evidence of differences in survival between women and men after age 108 in the Italian data and the International Database on Longevity, but survival is lower for men in the French data.

Are We Approaching a Biological Limit to Human Longevity?

Until recently human longevity records continued to grow in history, with no indication of approaching a hypothetical longevity limit. Also, earlier studies found that age-specific death rates cease to increase at advanced ages (mortality plateau) suggesting the absence of fixed limit to longevity too. In this study, we reexamine both claims with more recent and reliable data on supercentenarians (persons aged 110 years and older). We found that despite a dramatic historical increase in the number of supercentenarians, further growth of human longevity records in subsequent birth cohorts slowed down significantly and almost stopped for those born after 1879. We also found an exponential acceleration of age-specific death rates for persons older than 113 years in more recent data. Slowing down the historical progress in maximum reported age at death and accelerated growth of age-specific death rates after age 113 years in recent birth cohorts may indicate the need for more conservative estimates for future longevity records unless a scientific breakthrough in delaying aging would happen. The hypothesis of approaching a biological limit to human longevity has received some empirical support and it deserves further study and testing.

Neuropsychology of aging

All people want to age "successfully," maintaining functional capacity and quality of life as they reach advanced age. Achieving this goal depends on preserving optimal cognitive and brain functioning. Yet, significant individual differences exist in this regard. Some older adults continue to retain most cognitive abilities throughout their lifetime. Others experience declines in cognitive and functional capacity that range from mild decrements in certain cognitive functions over time to severe dementia among those with neurodegenerative diseases. Even among relatively healthy "successful agers," certain cognitive functions are reduced from earlier levels. This is particularly true for cognitive functions that are dependent on cognitive processing speed and efficiency. Working memory and executive and attentional functions tend to be most vulnerable. Learning and memory functions are also usually reduced, although in the absence of neurodegenerative disease learning and retrieval efficiency rather than memory storage are affected. Other functions, such as visual perception, language, semantics, and knowledge, are often well preserved. Structural, functional, and physiologic/metabolic brain changes correspond with age-associated cognitive decline. Physiologic and metabolic mechanisms, such as oxidative stress and neuroinflammation, may contribute to these changes, along with the contribution of comorbidities that secondarily affect the brain of older adults. Cognitive frailty often corresponds with physical frailty, both affected by multiple exogenous and endogenous factors. Neuropsychologic assessment provides a way of measuring the cognitive and functional status of older adults, which is useful for monitoring changes that may be occurring. Neuroimaging is also useful for characterizing age-associated structural, functional, physiologic, and metabolic brain changes, including alterations in cerebral blood flow and metabolite concentrations. Some interventions that may enhance cognitive function, such as cognitive training, neuromodulation, and pharmacologic approaches, exist or are being developed. Yet, preventing, slowing, and reversing the adverse effects of cognitive aging remains a challenge.

Are We Reaching the Limits of Homo sapiens?

Echoing scientific and industrial progress, the Twentieth century was an unprecedented period of improvement for human capabilities and performances, with a significant increase in lifespan, adult height, and maximal physiological performance. Analyses of historical data show a major slow down occurring in the most recent years. This triggered large and passionate debates in the academic scene within multiple disciplines; as such an observation could be interpreted as our upper biological limits. Such a new phase of human history may be related to structural and functional limits determined by long term evolutionary constraints, and the interaction between complex systems and their environment. In this interdisciplinary approach, we call into question the validity of subsequent forecasts and projections through innovative and related biomarkers such as sport, lifespan, and height indicators. We set a theoretical framework based on biological and environmental relevance rather than using a typical single-variable forecasting approach. As demonstrated within the article, these new views will have major social, economical, and political implications.