Figure 2. Asthma/COPD overlap in WTC-exposed firefighters who had a bronchodilator PFT.
The Venn diagram demonstrates abnormalities on bronchodilator PFTs obtained via the WTC treatment program. Isolated-asthma was diagnosed in 202 individuals who had FEV1 bronchodilator response of greater than 12% and 200 ml. Isolated-COPD was diagnosed in 215 individuals who had a post-bronchodilator FEV1 /FVC ratio <0.70. Asthma COPD/overlap was diagnosed in 99 who had both a FEV1 bronchodilator response >12% and 200 ml, and a FEV1/FVC ratio <0.70. The remainder of the study population (1,621) did not have a bronchodilator response or airflow limitation.