exposure in an array of risky occupations. These risk
factors, taken as a whole, accounted for 21% of the
variability in dyspnea.
After adjustment for patient-speciﬁc risk factors in the
ﬁrst stage analysis, we adjusted for spirometry-deﬁned
disease (PRISm, asthma, COPD, or normal
spirometry) in Table 5. Adjustment for disease
classiﬁcation accounted for 12% of the total variability
of dyspnea.
Table 6 presents the contribution of lung function
measures of physiologic impairment after accounting for
patient-related risk factors and disease classiﬁcation. For
the PRISm disease group, a higher post-BD FEV1/FVC
ratio and a lower post-BD FEV1 % predicted value were
associated with greater dyspnea impact. For the COPD
disease group, a lower post-BD FEV1/FVC ratio was
associated with greater dyspnea impact. Reversibility of
FEV1 was associated with higher dyspnea impact only in
patients with asthma or COPD. Lung function measures
of disease severity accounted for 2% of the variability in
dyspnea.
After adjusting for age, sex, and BMI, dyspnea was
negatively associated with all domains of quality of life,
including physical functioning (coefﬁcient, /C0 0.655;
P < .001), role limitations due to physical health
(coefﬁcient, /C0 0.628; P < .001), general health
(coefﬁcient, /C0 0.382; P < .001), and total score
(coefﬁcient, /C0 0.473; P < .001) (Table 7).
After adjusting for age, sex, and BMI, dyspnea was
associated with an increased likelihood of annual visits
to health care providers for respiratory complaints (OR,
TABLE 3] Intergroup Comparisons of Dyspnea Impact
Pairwise Comparison Mean Dyspnea Score (95% CI) Mean Difference (95% CI) P Value
Control 13.8 (11.8-15.7) /C0 38.0 (/C0 41.1 to/C0 34.9) < .001
Normal spirometry 51.8 (50.7-52.8)
Control 13.8 (11.8-15.7) /C0 43.7 (/C0 47.6 to/C0 39.8) < .001
COPD 57.5 (55.1-59.9)
Control 13.8 (11.8-15.7) /C0 42.8 (/C0 46.9 to/C0 38.7) < .001
Asthma 56.6 (53.9-59.3)
Control 13.8 (11.8-15.7) /C0 49.2 (/C0 53.7 to/C0 44.6) < .001
PRISm 63.0 (59.5-66.4)
Normal spirometry 51.8 (50.7-52.8) 5.7 (3.0 to 8.4) < .001
COPD 57.5 (55.1-59.9)
Normal spirometry 51.8 (50.7-52.8) 4.8 (1.8, 7.8) .002
Asthma 56.6 (53.9-59.3)
Normal spirometry 51.8 (50.7-52.8) 11.2 (7.5 to 14.8) < .001
PRISm 63.0 (59.5-66.4)
PRISm 63.0 (59.5-66.4) 5.5 (1.1 to 9.8) .014
COPD 57.5 (55.1-59.9)
PRISm 63.0 (59.5-66.4) 6.4 (1.9 to 10.9) .005
Asthma 56.6 (53.9-59.3)
Asthma 56.6 (53.9-59.3) 0.9 (/C0 2.8 to 4.7) .63
COPD 57.5 (55.1-59.9)
PRISm ¼ preserved ratio impaired spirometry.
Dyspnea assessment 
100
80
60
40
20
Normal
spirometry
Asthma COPD PRISm Healthy
control
participants
0
Figure 2 – Box plot demonstrating dyspnea impact according to
spirometry disease classiﬁcation. The center line marks the median. The
boxes span the interquartile range (IQR). The outer fences are set at
distances 1.5 /C2 IQR from the box. Outliers appear as plotted dots.
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