Table 2.

Univariate models^* of exercise capacity, dyspnea, and lung function as determinants of health-related quality of life.

Variable	MOS SF-36 PCS Score†		MOS SF-36 MCS Score†		SGRQ-TS‡
	Unadjusted Coefficient (95% CI)	p-Value	Unadjusted Coefficient (95% CI)	p-Value	Unadjusted Coefficient (95% CI)	p-Value
6MWT Distance	0.02	<0.001	0.02	<0.001	−0.04	<0.001
	(0.01 to 0.02)		(0.01 to 0.02)		(−0.05 to −0.04)
Maximal CPET Workload	0.08	<0.001	0.08	<0.001	−0.18	<0.001
	(0.06 to 0.09)		(0.05 to 0.10)		(−0.21 to −0.15)
UCSD SOBQ Total Score	−0.18	<0.001	−0.19	<0.001	0.46	<0.001
	(−0.19 to −0.16)		(−0.22 to −0.17)		(0.44 to 0.48)
6MWT Borg	−0.75	<0.001	−0.52	<0.001	1.7	<0.001
	(−0.92 to −0.58)		(−0.76 to −0.27)		(1.4 to 2.0)
CPET Borg	−0.47	<0.001	−0.33	0.0045	1.1	<0.001
	(−0.63 to −0.31)		(−0.56 to −0.10)		(0.80 to 1.4)
FEV1 % Predicted, After BD	0.14	<0.001	0.02	NS	−0.33	<0.001
	(0.08 to 0.19)		(−0.06 to 0.10)		(−0.42 to −0.23)
RV/TLC Ratio, After BD	−9.5	<0.001	−11	<0.001	21	<0.001
	(−14 to −5.1)		(−18 to −4.9)		(13 to 29)
DLCO, % Predicted	0.06	0.002	0.07	0.01	−0.16	<0.001
	(0.02 to 0.09)		(0.02 to 0.12)		(−0.22 to −0.09)

^*Example of univariate model: MOS SF-36 PCS Score = (0.02) × (6MWT Distance).

^†Higher score indicates better health status.

^‡Lower score indicates better health status.

6MWT = 6-minute walk test; BD = bronchodilator; Borg = Borg score for breathlessness; CI = confidence interval; CPET = cardiopulmonary exercise testing; DLCO = single-breath diffusing capacity of the lung for carbon monoxide; FEV₁ = forced expiratory volume in 1 second; MCS = Mental Component Summary; MOS SF-36 = Medical Outcomes Study 36-Item Short Form; NS = nonsignificant; PCS = Physical Component Summary; RV = residual volume; SGRQ-TS = St. George’s Respiratory Questionnaire total score; TLC = total lung capacity; UCSD SOBQ = University of California, San Diego Shortness of Breath Questionnaire.