Content validity and psychometric evaluation of Functional Assessment of Chronic Illness Therapy-Fatigue in patients with psoriatic arthritis

Journal of Patient-Reported Outcomes

Table 3 Correlations to assess the convergent validity of FACIT-Fatigue vs. other measures in patients with PsA

	PD1: OPAL Beyond baseline data pooled with OPAL Broaden Month 12 data, Pearson correlation coefficient			PD2: OPAL Broaden baseline data pooled with OPAL Beyond Month 6 data, Pearson correlation coefficient
FACIT-Fatigue vs.:	Experience domain	Impact domain	Total score	Experience domain	Impact domain	Total score
SF-36
Bodily pain	0.71	0.69	0.72	0.66	0.64	0.68
General health	0.57	0.55	0.58	0.59	0.55	0.59
Mental health	0.65	0.64	0.66	0.65	0.65	0.67
Physical functioning	0.64	0.69	0.69	0.56	0.62	0.62
Role emotional	0.63	0.70	0.70	0.56	0.64	0.63
Role physical	0.71	0.75	0.76	0.63	0.71	0.70
Social functioning	0.71	0.78	0.78	0.66	0.73	0.72
Vitality	0.83	0.75	0.81	0.81	0.75	0.81
Health transition	−0.33	−0.29	−0.32	−0.35	−0.33	−0.35
Mental component	0.68	0.70	0.71	0.66	0.69	0.70
Physical component	0.64	0.65	0.67	0.58	0.60	0.61
ISI	−0.42	−0.37	−0.41	−0.43	−0.41	−0.44
DLQI total score	−0.43	−0.43	−0.44	−0.43	−0.48	−0.48
PtGA	−0.64	−0.60	−0.64	−0.61	−0.57	−0.61
PtJA	−0.65	−0.62	−0.65	−0.61	−0.57	−0.61
PtSA	−0.47	−0.45	−0.47	−0.44	−0.44	−0.46

All results P < 0.0001. Correlation coefficients are all in the expected direction
DLQI Dermatology Life Quality Index, FACIT-Fatigue Functional Assessment of Chronic Illness Therapy-Fatigue, ISI Itch Severity Item; PD1/2 Pooled Data 1/2, PtGA Patient’s Global Assessment of Psoriasis and Arthritis (a component of the PtGJS-VAS), PtGJS Patient’s Global Joint and Skin Assessment, PtJA Patient’s Joint Assessment (a component of the PtGJS-VAS), PtSA Patient’s Skin Assessment (a component of the PtGJS-VAS), PsA psoriatic arthritis, SF-36 Short Form Survey-36, VAS Visual Analog Scale