title: A comparison between uni- and multidimensional frailty measures: prevalence, functional status, and relationships with disability.
abstract: BACKGROUND
  Over the years, a plethora of frailty assessment tools has been developed. These instruments can be basically grouped into two types of conceptualizations - unidimensional, based on the physical-biological dimension - and multidimensional, based on the connections among the physical, psychological, and social domains. At present, studies on the comparison between uni- and multidimensional frailty measures are limited.
  
  
  OBJECTIVE
  The aims of this paper were: 1) to compare the prevalence of frailty obtained using a uni- and a multidimensional measure; 2) to analyze differences in the functional status among individuals captured as frail or robust by the two measures; and 3) to investigate relations between the two frailty measures and disability.
  
  
  METHODS
  Two hundred and sixty-seven community-dwelling older adults (73.4±6 years old, 59.9% of women) participated in this cross-sectional study. The Cardiovascular Health Study (CHS) index and the Tilburg Frailty Indicator (TFI) were used to measure frailty in a uni- and multidimensional way, respectively. The International Physical Activity Questionnaire, the Center of Epidemiologic Studies Depression scale, and the Loneliness Scale were administered to evaluate the functional status. Disability was assessed using the Groningen Activity Restriction Scale. Data were treated with descriptive statistics, one-way analysis of variance, correlations, and receiver operating characteristic analyses through the evaluation of the areas under the curve.
  
  
  RESULTS
  Results showed that frailty prevalence rate is strictly dependent on the index used (CHS =12.7%; TFI =44.6%). Furthermore, frail individuals presented differences in terms of functional status in all the domains. Frailty measures were significantly correlated with each other (r=0.483), and with disability (CHS: r=0.423; TFI: r=0.475). Finally, the area under the curve of the TFI (0.833) for disability was higher with respect to the one of CHS (0.770).
  
  
  CONCLUSIONS
  Data reported here confirm that different instruments capture different frail individuals. Clinicians and researchers have to consider the different abilities of the two measures to detect frail individuals.
authors.affiliation: Department of Psychology, University of Torino, Torino, Italy ; Department of Developmental Psychology, Rijksuniversiteit Groningen, Groningen, the Netherlands.
authors.forename: Mattia
authors.initials: M
authors.lastname: Roppolo
authors.affiliation: Department of Psychology, University of Torino, Torino, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Mulasso
authors.affiliation: Faculty of Health, Sports and Social Work, Inholland University of Applied Sciences, Amsterdam, the Netherlands ; Zonnehuisgroep Amstelland, Amstelveen, the Netherlands.
authors.forename: Robbert J
authors.initials: RJ
authors.lastname: Gobbens
authors.affiliation: Department of Psychology, University of Torino, Torino, Italy.
authors.forename: Cristina O
authors.initials: CO
authors.lastname: Mosso
authors.affiliation: Department of Psychology, University of Torino, Torino, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Rabaglietti
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D016330:Frail Elderly; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D007558:Italy; D008297:Male; D015995:Prevalence; D011569:Psychiatric Status Rating Scales
keywords: active aging; functional decline; health outcomes; indexes selection; older adults