Table 3.

Known-groups validity of L-PF-35 Dyspnea domain scores at baseline

Anchor Variable	N	L-PF-35 Dyspnea domain score	p
UCSD SOBQ			< 0.0001
≥60 30 < FVC%<60 ≤30*	13 15 12	39.2 ± 18.1 21.9 ± 12.1 5.6 ± 5.7
SGRQ Activity			< 0.0001
≥60 40 < FVC%<60 ≤40*	23 11 6	32.7 ± 17.5 13.4 ± 6.8 0.7 ± 1.7
FVC%			0.01
≤ 55 55 < FVC%<70 ≥70*	10 24 6	33.5 ± 18.5 20.9 ± 18.4 11.1 ± 9.8
DLCO%			0.04
≤ 40 40 < FVC%<60 ≥60*	9 20 11	32.4 ± 18.7 22.0 ± 19.5 15.7 ± 14.2
Rest O2			0.02
Yes No*	17 23	30.0 ± 16.1 17.2 ± 18.7

*Reference group; FVC% = percentage of the predicted forced vital capacity; DLCO% = percentage of the predicted diffusing capacity of the lung for carbon monoxide; L-PF = 35-item Living with Pulmonary Fibrosis Questionnaire; SGRQ = St. George’s Respiratory Questionnaire; UCSD SOBQ = University of California San Diego Shortness of Breath Questionnaire