OMERACT Core Outcome Sets
What is a Core Outcome Set (COS)?
A Core Outcome Set (COS) is an agreed minimum set of outcome domains and corresponding measurement instruments that should be measured and reported in all clinical trials or studies for a specific health condition or intervention. These sets ensure consistency, comparability, and relevance of research findings across studies—supporting decision-making by patients, clinicians, regulators, and policymakers.
OMERACT COS are developed using a rigorous, transparent, and consensus-driven process that includes perspectives from researchers, clinicians, methodologists, regulators, and—critically—patient research partners (PRPs). This ensures the outcomes reflect what matters most to those living with the condition.
Explore Published OMERACT Core Outcome Sets
Below is a list of published Core Outcome Sets that have been developed through the OMERACT process. Each set includes links to the working group webpages to find relevant publications and ongoing updates.
| Condition | Core Domains | Endorsed Instruments | Working Group Page |
| Joint Health Conditions | |||
| Axial Spondyloarthritis | Disease Activity | ASDAS (Ankylosing Spondylitis Disease Activity Score) | Visit WG Webpage |
| Patient global assessment of disease activity (NRS) | |||
| SPARCC MRI activity of the SIJ | |||
| SPARCC MRI activity of the spine | |||
| Fatigue | NRS fatigue (BASDAI Q1) | ||
| Morning Stiffness | Severity and duration of stiffness (BASDAI (Q5 +Q6)/2) | ||
| Overall Functioning & Health | ASAS-HI | ||
| Pain | NRS total back pain (BASDAI Q2) | ||
| Physical Functioning | BASFI | ||
| Adverse Events including Death | |||
| Circumstance-dependent Core Domains: | |||
| Extra-musculoskeletal manifestations | AAU | ||
| IBD | |||
| Psoriasis | |||
| Peripheral manifestations | 44 swollen joint count | ||
| Dactylitis count (including active fingers and/or toes) | |||
| MASES | |||
| Structural Damage | mSASSS | ||
| Gout - Acute | Activity Limitations | Visit WG Webpage | |
| Joint Swelling | 4-point Likert Scale | ||
| Joint Tenderness | 4-point Likert Scale | ||
| Pain | 5-point Likert Sale or VAS | ||
| Patient Global Assessment | 5-point Likert Scale | ||
| Gout - Chronic | Acute Gout Attack | ||
| Activity Limitations | |||
| Health-Related Quality of Life (HRQoL) | |||
| Pain | |||
| Patient Global Assessment | |||
| Serum Urate | |||
| Tophus Burden | |||
| Hand Osteoarthritis (OA) | Hand Strength | Visit WG Webpage | |
| Health-Related Quality of Life (HRQoL) | |||
| Joint activity | |||
| Pain | |||
| Patient Global Assessment | |||
| Physical Function | AUSCAN | ||
| MHQ | |||
| Hip & Knee Osteoarthritis (OA) | Joint Structure | Visit WG Webpage | |
| Pain | |||
| Patient Global Assessment | |||
| Physical Function | |||
| Health-Related Quality of Life (HRQoL) | |||
| Adverse events including death | |||
| Juvenile Idiopathic Arthritis (JIA) | Activity limitations/physical function | Visit WG Webpage | |
| Joint inflammatory signs | |||
| Pain | |||
| Patient perception of overall well-being related to disease •Overall well-being •Disease activity | |||
| Adverse events including death | |||
| Polymyalgia Rheumatica (PMR) | Pain | Visit WG Webpage | |
| Physical Function | |||
| Stiffness | |||
| Systemic Inflammation (laboratory blood tests) | |||
| Adverse Events including Death | |||
| Psoriatic Arthritis (PsA) | Fatigue | Visit WG Webpage | |
| HRQOL | PsAIS12 | ||
| MSK Disease Activity | 66/68 Joint Count | ||
| Pain | |||
| Physical function | HAQ-DI | ||
| SF-36 | |||
| Physician’s Global | |||
| Skin Disease Activity | |||
| Systemic Inflammation | |||
| Rheumatoid Arthritis | Acute phase reactants | Visit WG Webpage | |
| Fatigue | |||
| Pain | |||
| Patient global assessment | |||
| Physical disability | |||
| Physician global assessment | |||
| Radiographs of joints (In studies of 1 or more years’ duration) | |||
| Swollen joints | |||
| Tender joints | |||
| Shoulder Disorders | Pain | Visit WG Webpage | |
| Patient global-shoulder | |||
| Physical function/activity; | |||
| Adverse Events including Death | |||
| Systemic Rheumatologic Health Conditions | |||
| ANCA-Associated Vasculitis | Disease Activity | Visit WG Webpage | |
| Health-Related Quality of Life (HRQoL) | |||
| Organ Damage Assessment | |||
| Adverse Events including Death | |||
| Behçet’s Syndrome | Disease Activity | Visit WG Webpage | |
| Health-Related Quality of Life (HRQoL) | |||
| New Organ Involvement | |||
| Adverse Events including Death | |||
| Circumstance-dependent Core Domains: | |||
| Mucocutaneous | |||
| Number of lesions | |||
| Pain of lesions | |||
| Central Nervous System | |||
| CNS Lesion | |||
| Cognitive Function | |||
| Neurologic Function | |||
| Gastrointestinal | |||
| Clinical GI Activity | |||
| Endoscopic GI Activity | |||
| Vascular | |||
| Vascular Lesion | |||
| Thrombophlebitis | |||
| Post-Thrombotic Syndrome | |||
| Musculoskeletal | |||
| Tender Joints | |||
| Swollen Joints | |||
| Eye | |||
| Visual Acuity | |||
| Frequency of Attacks | |||
| Ocular Severity | |||
| Vascular Leakage | |||
| CTD-ILD | Cough | Visit WG Webpage | |
| Dyspnea | |||
| Functional Status | |||
| HRQOL | |||
| Lung Imaging | |||
| Lung Physiology | Forced Vital Capacity | ||
| Adverse Events including Death | |||
| Fibromyalgia | Fatigue | Visit WG Webpage | |
| Function | |||
| Joint Tenderness | |||
| Multidimensional | |||
| Pain | |||
| Patient Global Assessment | |||
| Sleep Disturbance | |||