title: Peak expiratory flow as a predictor of subsequent disability and death in community-living older persons.
abstract: OBJECTIVE
  To determine whether peak expiratory flow (PEF), when expressed by a validated method using standardized residual (SR) percentile, is associated with subsequent disability and death in older persons.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  New Haven, Connecticut.
  
  
  METHODS
  Seven hundred fifty-four initially nondisabled, community-living persons aged 70 and older.
  
  
  METHODS
  PEF was assessed at baseline along with chronic conditions and smoking history. The onset of persistent disability in activities of daily living (ADLs), continuous mobility disability, and death were ascertained during monthly interviews over a 5-year period.
  
  
  RESULTS
  Participants' mean age was 78.4, 63.7% had a smoking history, and 17.4% reported chronic lung disease. The incidence rates per 100 person-months were 1.00 (95% confidence interval (CI)=0.90-1.12) for ADL disability, 0.80 (95% CI=0.70-0.93) for mobility disability, and 0.44 (95% CI=0.38-0.51) for death. At a PEF less than 10(th) SR percentile, identifying nearly one-quarter of the cohort, hazard ratios (HRs) adjusted for multiple confounders, including age, smoking, and chronic lung disease, demonstrated a greater risk of ADL disability (HR=1.79, 95% CI=1.23-2.62), mobility disability (HR=1.89, 95% CI=1.15-3.10), and death (HR=2.31, 95% CI=1.29-4.12).
  
  
  CONCLUSIONS
  In an elderly cohort, it was found that low PEF, when expressed as an SR percentile, is independently associated with subsequent disability and death. These results support the use of PEF as a potentially valuable risk assessment tool in community-living older persons.
authors.affiliation: Department of Internal Medicine, School of Medicine, Yale University, New Haven, Connecticut 06504, USA. carlos.fragoso@ynhh.org
authors.forename: Carlos A Vaz
authors.initials: CA
authors.lastname: Fragoso
authors.forename: Evelyne A
authors.initials: EA
authors.lastname: Gahbauer
authors.forename: Peter H
authors.initials: PH
authors.lastname: Van Ness
authors.forename: John
authors.initials: J
authors.lastname: Concato
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Gill
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D003237:Connecticut / Q000453:epidemiology; D004185:Disability Evaluation; D005260:Female; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008136:Longevity; D008297:Male; D051346:Mobility Limitation; D009026:Mortality; D010366:Peak Expiratory Flow Rate; D016016:Proportional Hazards Models; D018570:Risk Assessment