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

Journal of Patient-Reported Outcomes

Table 4 Clinically important difference (CID) and responder definition (RD) estimations for FACIT-Fatigue in patients with PsA

Model	Analysis	Anchor	Study data	Experience domain	Impact domain	Total score
				Clinically important difference (SE) [95% CI]
Repeated measures model-CID	Main analysis	PtGA	Pooled	1.45 (0.04) [1.38, 1.52]	1.73 (0.05) [1.63, 1.82]	3.12 (0.08) [2.97, 3.27]
	Sensitivity analysis	PtGA	OPAL Broaden	1.39 (0.05) [1.30, 1.48]	1.66 (0.06) [1.53, 1.78]	3.00 (0.10) [2.80, 3.19]
		PtGA	OPAL Beyond	1.53 (0.06) [1.42, 1.64]	1.82 (0.08) [1.67, 1.97]	3.29 (0.12) [3.04, 3.53]
		SF-36 Vitality	Pooled	1.06 (0.01) [1.03, 1.08]	1.21 (0.02) [1.17, 1.25]	2.25 (0.03) [2.18, 2.31]
				Effect size (SD)
Repeated measures model-CID	Main analysis	PtGA	Pooled	8.73 (4.54)	18.93 (6.88)	27.66 (10.95)
	Sensitivity analysis	PtGA	OPAL Broaden	9.13 (4.34)	19.56 (6.57)	28.69 (10.47)
			OPAL Beyond	8.30 (4.72)	18.25 (7.14)	26.54 (11.35)
				Responder definition (SE) [95% CI]
Repeated measures model-RD	Main analysis	SGIC	Pooled	1.67 (0.09) [1.49, 1.86]	2.12 (0.12) [1.88, 2.37]	3.76 (0.20) [3.37, 4.15]
	Sensitivity analysis		OPAL Broaden	1.54 (0.12) [1.31, 1.77]	2.02 (0.15) [1.72, 2.33]	3.52 (0.25) [3.03, 4.01]
	Sensitivity analysis		OPAL Beyond	1.91 (0.16) [1.60, 2.23]	2.30 (0.20) [1.90, 2.70]	4.19 (0.33) [3.54, 4.85]

Pooled data: OPAL Broaden and OPAL Beyond
CI confidence interval, CID clinically important difference, FACIT-Fatigue Functional Assessment of Chronic Illness Therapy-Fatigue, PsA psoriatic arthritis, PtGA Patient’s Global Assessment of Psoriasis and Arthritis, RD responder definition, RMM repeated measures model, SD standard deviation, SE standard error, SF-36 Short Form Survey-36, SGIC Subject Global Impression of Change