title: Classification of frailty using the Kihon checklist: A cluster analysis of older adults in urban areas.
abstract: OBJECTIVE
  Frailty is an important predictor of the need for long-term care and hospitalization. Our aim was to categorize frailty in community-dwelling older adults.
  
  
  METHODS
  The present study was carried out in 2011-2013, and consisted of 1380 individuals over 65 years of age. Participants completed the Kihon checklist, which is widely used to assess frailty in Japan, and their physical, cognitive and social function was evaluated. Non-hierarchical cluster analysis was used to statistically categorize frailty. The optimum number of clusters was determined as the point at which the external reference values (instrumental activity of daily living score, grip power, 10-m walk time, body mass index, portable fall risk index, occlusal force and Mini-Mental State Examination score) differed.
  
  
  RESULTS
  According to the Kihon checklist, 369 (26.7%) of the 1380 study participants were considered frail. When the cluster number was increased from two to six, the scores in each subdomain of the Kihon checklist significantly differed. The estimated minimum number of clusters was five, and each of the five cluster groups had distinct characteristics. The numbers of participants in cluster groups 1-5 were 105, 78, 62, 71 and 53, respectively.
  
  
  CONCLUSIONS
  We identified five types of frailty in community-dwelling older adults in Japan: "experience of falling," "pre-frailty," "oral frailty," "housebound" and "severe frailty." Geriatr Gerontol Int 2017; 17: 69-77.
authors.affiliation: Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kera
authors.affiliation: Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kawai
authors.affiliation: Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Hideyo
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Hirano
authors.affiliation: University of Tokyo Health Sciences, Tokyo, Japan.
authors.forename: Motonaga
authors.initials: M
authors.lastname: Kojima
authors.affiliation: Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fujiwara
authors.affiliation: Toho University, Tokyo, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Ihara
authors.affiliation: Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Obuchi
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D057189:Checklist; D016000:Cluster Analysis; D003071:Cognition; D005260:Female; D016330:Frail Elderly; D015577:Geriatric Assessment / Q000145:classification*; D006304:Health Status; D006801:Humans; D007564:Japan; D008019:Life Style; D008297:Male; D053580:Muscle Strength; D012111:Residence Characteristics; D012919:Social Behavior; D014504:Urban Health / Q000145:classification*
keywords: Japan; cluster analysis; frail; phenotype; urban population