Chronic obstructive pulmonary disease in older persons: A comparison of two spirometric definitions
Received 18 August 2009; accepted 20 October 2009. published online 04 March 2010.
Summary
Background
Among older persons, we previously endorsed a two-step spirometric definition of chronic obstructive pulmonary disease (COPD) that requires a ratio of forced expiratory volume in 1sec to forced vital capacity (FEV1/FVC) below .70, and an FEV1 below the 5th or 10th standardized residual percentile (“SR-tile strategy”).
Objective
To evaluate the clinical validity of an SR-tile strategy, compared to a current definition of COPD, as published by the Global Initiative for Obstructive Lung Disease (GOLD-COPD), in older persons.
Methods
We assessed national data from 2480 persons aged 65–80 years. In separate analyses, we evaluated the association of an SR-tile strategy with mortality and respiratory symptoms, relative to GOLD-COPD. As per convention, GOLD-COPD was defined solely by an FEV1/FVC<.70, with severity staged according to FEV1 cut-points at 80 and 50 percent predicted (%Pred).
Results
Among 831 participants with GOLD-COPD, the risk of death was elevated only in 179 (21.5%) of those who also had an FEV1<5th SR-tile; and the odds of having respiratory symptoms were elevated only in 310 (37.4%) of those who also had an FEV1<10th SR-tile. In contrast, GOLD-COPD staged at an FEV1 50–79%Pred led to misclassification (overestimation) in terms of 209 (66.4%) and 77 (24.6%) participants, respectively, not having an increased risk of death or likelihood of respiratory symptoms.
Conclusion
Relative to an SR-tile strategy, the majority of older persons with GOLD-COPD had neither an increased risk of death nor an increased likelihood of respiratory symptoms. These results raise concerns about the clinical validity of GOLD guidelines in older persons.
ABSTRACT