Table 1 An overview of the response criteria.

PsARC	ACR criteria	EULAR criteria
Response is defined by improvement in at least 2 of the 4 following measures, one of which must be joint swelling or tenderness, and no worsening in any of the 4 measures:PtGA of articular disease (1–5) and PhGA of articular disease (1–5): improvement = decrease by one category, worsening = increase by one category. Joint pain/tenderness score and joint swelling score: improvement = decrease by 30%, worsening = increase by 30%.	Improvement is defined by at least 20% improvement in TJC and in SJC, and at least 20% improvement in 3 of the 5 measures:ESR or CRPPhGA of disease activityPtGA of disease activityPatient assessment of painDisability	A good response is defined as reaching a DAS ⩽2.4 or a DAS28 ⩽3.2 (“low” disease activity) in combination with an improvement >1.2 (twice the measurement error) in DAS or DAS28. A non‐response is defined as an improvement ⩽0.6, and also as an improvement ⩽1.2 with a DAS>3.7 or DAS28>5.1 (“high” disease activity). All other possibilities are defined as a moderate response.

ACR, American College of Rheumatology⁵; CRP, C reactive protein; DAS, Disease Activity Score⁷; ESR, erythrocyte sedimentation rate; EULAR, European League Against Rheumatism⁸; PhGA, physician global assessment; PsARC, psoriatic arthritis response criteria¹⁰; PtGA, patient global assessment; SJC, swollen joint count; TJC, tender joint count.