Chronic obstructive pulmonary disease in older persons: A comparison of two spirometric definitions

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.

Keywords: COPD, Spirometry, Respiratory symptoms, Mortality