Table 1.

Terminology used to describe the natural history of RA.

TermDefinition
Pre-RA, preclinical RAThe stage prior to the development of clinical RA. May be defined in several ways, including presence of autoantibodies, abnormal symptoms, and imaging findings.
At-riskAny state in which an individual has a higher-than-average risk of developing RA but does not have current IA (ie, being an FDR of a patient with RA, presence of autoantibodies). Notably, a EULAR task force that included individuals with clinical RA, as well as individuals who are at-risk for future RA, determined that the term “pre-RA” should only be used retrospectively once it was known that an individual developed clinical RA.32 As such, the term “at-risk individual” is often used to describe individuals who exhibit some risk factors for future RA but whose future status of clinical RA is unknown.
First-degree relative (FDR)An individual who is related in the first degree (ie, parent, full sibling, offspring) to an individual with a specific disease. An FDR shares genetic and often environmental risk factors for developing the disease of interest.
Clinically suspect arthralgia (CSA)A combination of signs and symptoms that is suggestive of the presence and/or risk for IA. This includes, but is not limited to, morning stiffness and pain in the small joints. The pain may or may not be elicited on physical examination.
Clinically apparent IAA clinical finding of joint synovitis in the absence of trauma that is suggestive of the earliest stage of RA. A joint with synovitis is typically tender on range of motion/palpation, swollen with a palpable effusion, and warmer than noninflamed joints.
Palindromic rheumatism (PR)Recurrent episodes of IA, typically involving the small joints of the hands and feet, that resolves spontaneously with limited or no symptoms between events. A subset of patients with PR will develop classifiable RA.
Subclinical IAThe presence of inflammation in a joint detected by imaging, typically by MRI or US, that is suggestive of IA, and a physical examination of the involved joint that is not suggestive of synovitis (ie, there is an absence of joint swelling).
Undifferentiated arthritisIA that does not fulfill established classification criteria for RA or any other disease.
Clinical RAClinically apparent IA, with or without autoantibodies, that a clinician diagnoses and treats as RA. This includes individuals who have classifiable RA and those who do not. For example, a patient with low positive ACPA/RF and 3 swollen small joints may not have classifiable RA but still be diagnosed and treated as having RA.
Classifiable RAA patient who meets established classification criteria for RA, either the 1987 ACR or 2010 ACR/EULAR criteria.1,2
Seropositive RAClinical RA with serum elevations of RA-associated antibodies, such as RF or ACPA.
Seronegative RAClinical RA without serum elevations of RA-associated antibodies, such as RF or ACPA.
Early RAA patient who meets classification criteria for RA for a short duration, typically < 1 yr, although definitions vary in the literature.
  • ACPA: anticitrullinated protein antibody; ACR: American College of Rheumatology; CRP: C-reactive protein; EULAR: European Alliance of Associations for Rheumatology; IA: inflammatory arthritis; MRI: magnetic resonance imaging; RA: rheumatoid arthritis; RF: rheumatoid factor; US: ultrasound.