No abstract

Japan's population is aging more rapidly than that of any other country. Frailty has recently been recognized as an important priority. Understanding the basic epidemiology of frailty in Japan, which is an example of a rapidly aging society, will be beneficial for Japan as well as other countries expecting an aging population. A systematic literature search of 11 electronic databases was conducted in March 2016 using a comprehensive set of Medical Subject Heading and text terms for any studies published in 2000 or later that report the prevalence of frailty among Japanese community-dwelling older people aged 65 years or older. A total of 1529 studies were identified in the systematic search, of which five studies were included in this review. The pooled prevalence of frailty, prefrailty, and robustness was 7.4% (95% confidence interval [CI], 6.1%–9.0%), 48.1% (95% CI, 41.6%–54.8%), and 44.4% (95% CI, 37.2%–51.7%), respectively. A significant degree of heterogeneity was observed. There was no evidence of publication bias. Age-stratified meta-analyses of four studies showed the pooled prevalence of frailty was 1.9%, 3.8%, 10.0%, 20.4%, and 35.1% for those aged 65–69, 70–74, 75–79, 80–84, and ≥85 years, respectively. Pooled prevalence of frailty was 8.1% for women and 7.6% for men. This review showed an overall pooled prevalence of frailty among Japanese community-dwelling older people of 7.4%. The age-stratified analysis suggested that Japanese older people are less frail before their late 70's but frailer in later life than older people in other countries. These findings provide important basic information for all parties involved in Japanese frailty research.

Frailty is a well-established risk factor for adverse health outcomes. However, little is known about the dynamic nature of frailty and the extent it can improve. The purposes of this study were to systematically search for studies examining frailty transitions over time among community-dwelling older people, and to synthesise pooled frailty transitions rates. Four electronic databases (Medline, Embase, PsycINFO and CINAHL) were searched in July 2018. Inclusion criteria were: prospective design, community-dwelling older people with mean age>60, using 5-item frailty phenotype criteria to define three states: robust, prefrail and frail and the numbers of participants with 9 frailty transition patterns based on frailty status at baseline and follow-up. Exclusion criteria were: selected populations, using fewer than 5 frailty phenotype criteria. Two investigators independently screened 504 studies for eligibility and identified 16 studies for this review. Data were extracted by the two investigators independently. Pooled rates of frailty transition patterns were calculated by random-effects meta-analysis. Among 42,775 community-dwelling older people from 16 studies with a mean follow-up of 3.9 years (range: 1-10 years), 13.7% (95%CI=11.7-15.8%) improved, 29.1% (95%CI=25.9-32.5%) worsened and 56.5% (95%CI=54.2-58.8%) maintained the same frailty status. Among those who were robust at baseline, pooled rates of remaining robust or transitioning to prefrail and frail were 54.0% (95%CI=48.8-59.1%), 40.6% (95%CI=36.7-44.7%) and 4.5% (95%CI=3.2-6.1%), respectively. Among those who were prefrail at baseline, corresponding rates to robust, prefrail and frail were 23.1% (95%CI=18.8-27.6%), 58.2% (95%CI=55.6-60.7%) and 18.2% (95%CI=14.9-21.7%), respectively. Among those who were frail at baseline, pooled rates of transitioning to robust, prefrail and remaining frail were 3.3% (95%CI=1.6-5.5%), 40.3% (95%CI=34.6-46.1%) and 54.5% (95%CI=47.6-61.3%), respectively. Stratified and meta-regression analyses showed age, gender and follow-up period were associated with frailty transition patterns. Older people make dynamic changes in their frailty status. Given that while one quarter of prefrail older people improved to robust only 3% of frail older people did, early interventions should be considered.

Background There is limited evidence on sarcopenia in Asian populations. This study aimed to clarify the prevalence, associated factors, and the magnitude of association with mortality and incident disability for sarcopenia and combinations of its components among Japanese community‐dwelling older adults. Methods We conducted a 5.8 year prospective study of 1851 Japanese residents aged 65 years or older (50.5% women; mean age 72.0 ± 5.9) who participated in health check‐ups. Sarcopenia was defined according to the Asian Working Group for Sarcopenia 2019 algorithm. Appendicular lean mass index (ALMI) was measured using direct segmental multi‐frequency bioelectrical impedance analysis. A Cox proportional hazards regression model was used to identify associations of sarcopenia and the combinations of its components with all‐cause mortality and incident disability. Results The prevalence of sarcopenia was 11.5% (105/917) in men and 16.7% (156/934) in women. Significant sarcopenia‐related factors other than ageing were hypoalbuminaemia, cognitive impairment, low activity, and recent hospitalization (all P‐values <0.05) among men and cognitive impairment (P = 0.004) and depressed mood (P < 0.001) among women. Individuals with sarcopenia had higher risks of mortality [hazard ratios (95% confidence interval): 2.0 (1.2–3.5) in men and 2.3 (1.1–4.9) in women] and incident disability [1.6 (1.0–2.7) in men and 1.7 (1.1–2.7) in women]. Compared with the individuals without any sarcopenia components, those having low grip strength and/or slow gait speed without low ALMI tended to have an increased risk of disability [1.4 (1.0–2.0), P = 0.087], but not mortality [1.3 (0.8–2.2)]. We did not find increased risks of these outcomes in participants having low ALMI in the absence of low grip strength and slow gait speed [1.2 (0.8–1.9) for mortality and 0.9 (0.6–1.3) for incident disability]. Conclusions Japanese older men and women meeting Asian criteria of sarcopenia had increased risks of all‐cause mortality and disability. There were no significant increased risks of death or incident disability for both participants with muscle weakness and/or low performance without low muscle mass and those with low muscle mass with neither muscle weakness nor low performance. Further studies are needed to examine the interaction between muscle loss, muscle weakness, and low performance for adverse health‐related outcomes.