Table 4.

Key outcome measures in common use for assessment of psoriatic arthritis

Outcome	Instrument	Main components	Reference
Disease activity	Composite measures
	ACR 20, 50, 70 response	Percentage improvement in tender and swollen joint counts in addition to improvement in three out of five measures: physician's and patient's assessment of disease activity, patient's assessment of pain, acute phase reactant, and functional questionnaire	[116]
	PsARC	Improvement by >1 point in both physician's and patient's assessment of disease activity in addition to >30% reduction in tender and swollen joint counts	[117]
	Skin disease
	PASI 50, 75	Percentage improvement in severity and extent of skin involvement	[118]
	Minimal disease activity	Having five of the following seven criteria: tender joint count <1; swollen joint count <1; PASI <1 or body surface area <3; patient pain VAS <15; patient global disease activity VAS <20; health assessment questionnaire <0.5; and tender entheseal points <1	[119]
Radiograph scoring	Sharp score	Joint erosion + joint narrowing scores	[120]

ACR, American College of Rheumatology; PASI, Psoriasis Area and Severity Index; PsARC, Psoriatic Arthritis Response Criteria; VAS, visual analogue scale.