Table 3.

Internal consistency reliably of the PsAID-12, as assessed using week 16 data

PsAID-12 score	Spearman rank correlation: item-corrected total score*	Cronbach’s alpha: standardised items†
PsAID-12 total score	–	0.95
PsAID-12 pain	0.85	0.95
PsAID-12 fatigue	0.85	0.95
PsAID-12 skin problems	0.62	0.95
PsAID-12 work/leisure activities	0.89	0.94
PsAID-12 functional capacity	0.90	0.94
PsAID-12 discomfort	0.86	0.94
PsAID-12 sleep disturbance	0.76	0.95
PsAID-12 coping	0.84	0.95
PsAID-12 anxiety/fear/uncertainty	0.58	0.95
PsAID-12 embarrassment/shame	0.57	0.95
PsAID-12 social participation	0.71	0.95
PsAID-12 depression	0.51	0.95

*p<0.001 for all correlations.

†Cronbach’s alpha was calculated with and without removal of individual PsAID-12 items.

PsAID-12, Psoriatic Arthritis Impact of Disease-12.