title: Reliability of a Frailty Index Based on the Clinical Assessment of Health Deficits in Male C57BL/6J Mice.
abstract: We investigated the reliability of a newly developed clinical frailty index (FI) that measures frailty based on deficit accumulation in aging mice. FI scores were measured by two different raters independently in a large cohort (n = 233) of 343-430 day-old male C57BL/6J mice. Inter-rater reliability was evaluated with correlation coefficients, the kappa statistic, and intra-class correlation coefficients (ICC) in three separate groups of mice (n = 45, 50, and 138 mice/group) sequentially over 3 months. After each group was evaluated, descriptions of techniques used to identify health deficits were amended. Mice had comparable overall FI scores regardless of rater (0.213±0.002 vs 0.212±0.002; p = .802), although discordant measures declined as techniques were refined. Correlation coefficients (r (2) values) between raters improved throughout the study and mean kappa values increased (mean ± SEM; 0.621±0.018, 0.764±0.017, and 0.836±0.009 for groups 1, 2, and 3; p < .05). Values for intra-class correlation coefficient also improved from .51 (95% confidence interval = 0.11-.73) to .74 (0.54-0.85) and .77 (0.67-.83). FI scores increased over 3 months (p < .05), but did not differ between raters. These results show a high overall inter-rater reliability when the clinical FI tool is used to assess frailty in a large cohort of mice.
authors.affiliation: Department of Pharmacology and.
authors.forename: Hirad A
authors.initials: HA
authors.lastname: Feridooni
authors.affiliation: Department of Pharmacology and.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Sun
authors.affiliation: Department of Medicine (Geriatric Medicine), Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Rockwood
authors.affiliation: Department of Pharmacology and Department of Medicine (Geriatric Medicine), Dalhousie University, Halifax, Nova Scotia, Canada. Department of Cardiovascular Physiology, University of Manchester, UK. susan.howlett@dal.ca.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Howlett
mesh_terms: D000375:Aging; D000818:Animals; D051379:Mice; D015588:Observer Variation; D011361:Professional Competence; D015203:Reproducibility of Results; D012108:Research Personnel
keywords: Ageing.; Deficit accumulation; Deficit index; Frailty index; Senescence