. Author manuscript; available in PMC: 2014 May 23.

Published in final edited form as: Heart Lung. 2013 Sep 20;42(6):465–472. doi: 10.1016/j.hrtlng.2013.08.008

Table 5.

Results from hierarchical regression models predicting exercise capacity (N = 596).

Predictors	Peak workload on cycle ergometer (watt)			6-minute walk distance (feet)

	R²	R² change	Beta	R²	R² change	Beta
Step 1^a	.340^*			.165^*
Step 2; symptom cluster subgroups	.353^*	.014^*	−6.66^*	.191^*	.025^*	−132.68^*
F equation	F_6,575 = 52.40, p = .0001			F_6,577 = 22.69, p = .0001
Step 2; dyspnea	.376^*	.036^*	−8.13^*	.212^*	.046^*	−134.51^*
F equation	F_6,575 = 57.68, p = .0001			F_6,577 = 25.81, p = .0001
Step 2; anxiety	.344^*	.005^*	−2.91^*	.178^*	.013^*	−71.32^*
F equation	F_6,575 = 50.30, p = .0001			F_6,577 = 21.25, p = .0001
Step 2; depression	.342	.002	−2.08	.181^*	.016^*	−77.37^*
F equation	F_6,575 = 49.81, p = .0001			F_6,577 = 20.89, p = .0001
Step 2; fatigue	.351^*	.011^*	−4.58^*	.176^*	.011^*	−66.19^*
F equation	F_6,575 = 51.72, p = .0001			F_6,577 = 20.55, p = .0001

All models in step 2 were analyzed separately.

FEV1, forced expiratory volume in 1 s; MOS-36, Medical Outcomes Study 36-Item Short Form Health Survey.

p value < .05.

Predictors in step 1 include age, gender, FEV1% predicted, education level, and economic status.