Validity and reliability of patient reported outcomes used in Psoriasis: results from two randomized clinical trials

Table 1 Means, Standard Deviations, and Coefficient α for Patient Reported Outcome Measures, Baseline and Week 12

	STUDY A						STUDY B
	Baseline			Week 12			Baseline			Week 12
Patient-reported outcome measure	N	Mean (s.d.)	Coefficient α	N	Mean (s.d.)	Coefficient α	N	Mean (s.d.)	Coefficient α	N	Mean (s.d.)	Coefficient α
PSA Frequency: 8-item scale	493	13.21 (5.07)	0.858	446	8.22 (5.57)	0.927	594	13.79 (5.22)	0.875	572	8.51 (6.24)	0.940
PSA Frequency: 7-item scale	493	n/a	0.865	446	n/a	0.922	594	n/a	0.876	572	n/a	0.936
PSA Severity: 8-item scale	494	14.08 (5.55)	0.874	445	8.55 (6.42)	0.942	595	14.38 (5.62)	0.891	573	8.66 (6.71)	0.946
PSA Severity: 7-item scale	494	n/a	0.874	445	n/a	0.939	595	n/a	0.889	573	n/a	0.941
DLQI	483	11.75 (6.80)	0.871	437	6.69 (6.51)	0.921	586	12.18 (6.71)	0.869	571	7.07 (6.74)	0.919
VAS Itch	497	5.90 (2.68)	n/a¹	446	3.74 (3.03)	n/a¹	-	-	-	-	-	-
NPS Itch	-	-	-	-	-	-	597	3.05 (1.41)	n/a¹	558	1.80 (1.50)	n/a¹

ISSN: 1477-7525