title: Frailty in the Honolulu-Asia Aging Study: deficit accumulation in a male cohort followed to 90% mortality.
abstract: BACKGROUND
  A frailty index (FI) based on the accumulation of deficits typically has a submaximal limit at about 0.70. The objectives of this study were to examine how population characteristics of the FI change in the Honolulu-Asia Aging Study cohort, which has been followed to near-complete mortality. In particular, we were interested to see if the limit was exceeded.
  
  
  METHODS
  Secondary analysis of six waves of the Honolulu-Asia Aging Study. Men (n = 3,801) aged 71-93 years at baseline (1991) were followed until death (N = 3,455; 90.9%) or July 2012. FIs were calculated across six waves and the distribution at each wave was evaluated. Kaplan-Meier analyses and Cox proportional hazard models were performed to examine the relationship of frailty with mortality.
  
  
  RESULTS
  At each wave, frailty was nonlinearly associated with age, with acceleration in later years. The distributions of the FIs were skewed with long right tails. Despite the increasing mortality in each successive wave, the 99% submaximal limit never exceeded 0.65. The risk of death increased with increasing values of the FI (eg, the hazard rate increased by 1.44 [95% CI = 1.39-1.49] with each increment in the baseline FI grouping). Depending on the wave, the median survival of people with FI more than 0.5 ranged 0.84-2.04 years.
  
  
  CONCLUSIONS
  Even in a study population followed to almost complete mortality, the limit to deficit accumulation did not exceed 0.65, confirming a quantifiable, maximum number of health deficits that older men can tolerate.
authors: Department of Medicine, Dalhousie University, Nova Scotia, Canada.
authors: Joshua J
authors: JJ
authors: Armstrong
authors: Department of Medicine, Dalhousie University, Nova Scotia, Canada.
authors: Arnold
authors: A
authors: Mitnitski
authors: Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Bethesda, Maryland.
authors: Lenore J
authors: LJ
authors: Launer
authors: Pacific Health Research & Education Institute, Honolulu, Hawaii.
authors: Lon R
authors: LR
authors: White
authors: Department of Medicine, Dalhousie University, Nova Scotia, Canada. kenneth.rockwood@dal.ca.
authors: Kenneth
authors: K
authors: Rockwood
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology* / Q000523:psychology; D044466:Asian People; D015331:Cohort Studies; D005500:Follow-Up Studies; D016330:Frail Elderly / Q000523:psychology / Q000706:statistics & numerical data; D006254:Hawaii / Q000453:epidemiology; D006801:Humans; D007564:Japan / Q000208:ethnology; D053208:Kaplan-Meier Estimate; D008297:Male; D009026:Mortality; D017711:Nonlinear Dynamics; D012307:Risk Factors
keywords: Deficit accumulation; Epidemiology; Frailty; Frailty index; Mortality.