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.DESIGN
Prospective cohort study.SETTING
New Haven, Connecticut.PARTICIPANTS
Seven hundred fifty-four initially nondisabled, community-living persons aged 70 and older.MEASUREMENTS
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 10th 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).CONCLUSION
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.