Lung function decline and outcomes in an elderly population.

Abstract

To determine the risk factors for and outcomes associated with the rapid decline in lung function in a cohort of elderly US adults. Data from 4923 adult participants aged 65 years and older at baseline in the Cardiovascular Health Study were analysed. Subjects were classified using a modification of the GOLD criteria for chronic obstructive pulmonary disease (COPD) and a "restricted" category (FEV1/FVC>or=70% and FVC<80% predicted) was added. Cox proportional hazard models were used to determine the risk of lung function decline over 4 years on subsequent mortality and COPD hospital admissions after adjusting for age, race, sex, smoking status, and other factors. Of the participants in the initial cohort, 3388 (68.8%) had spirometric tests at the year 4 visit. Participants with GOLD stages 3 or 4 COPD at baseline were less likely than normal subjects to have follow up spirometric tests (52.7% v 77.9%, p<0.01) and were more likely to be in the most rapidly declining quartile of FEV1 (28.2% v 21.3%, p<0.01) with an annual loss of FEV1 of at least 3.5%. Overall, being in the most rapidly declining quartile of FEV1 from baseline to year 4 was associated with an increased risk of admission to hospital for COPD (adjusted hazard ratio (HR) 1.6, 95% confidence interval (CI) 1.3 to 2.0) and all-cause death (adjusted HR 1.5, 95% CI 1.2 to 1.7) over an additional 7 years of follow up. More rapid decline in lung function is independently associated with a modest increased risk of hospital admissions and deaths from COPD in an elderly cohort of US participants.