Table 2.

ReA diagnosis methodology of included studies

Study	Classification criteria used	Screening tool used	Full evaluation
Carter et al. [31]	The European Spondylarthropathy Study Group (ESSG) criteria [33] (excluding plain radiographs of the sacroiliac joints).	Standardised questionnaire of 13 questions by telephone by rheumatology sub-speciality residents, including new arthritis symptoms or other symptoms of ReA such as conjunctivitis, uveitis and enthesitis.	Details obtained for any positive responses to the questionnaire during the telephone interview. In person review declined by participants.
Rich et al. [30]	Features of ReA considered: oligoarthritis, enthesitis in any location, inflammatory axial pain or mucocutaneous inflammation (conjunctivitis, oral ulcers, circinate balanitis, or keratoderma blennorrhagica).	A standardised questionnaire of 8 questions derived from QUEST 2 (Questionnaire Utilizing Epidemic Spondyloarthropathy Traits) [32]. In the last 60 days: joint pain, joint swelling, morning stiffness, heel pain, inflammation of the eyes, oral mucosal lesions, or skin rashes involving the palms or soIes.	Patients with positive answers to any question evaluated by a rheumatologist by history and physical examination with particular attention to features of ReA.
Keat et al.[29]	No specific classification criteria given, but state arthritis after a proven or putative infection of the genital tract considered as sexually acquired reactive arthritis (SARA), the arthritis (referred to as “reactive”) being a sterile inflammation of the synovial membrane, tendons, and fascia.	No screening tool described, not clear if used.	Method of full examination not described. Excluded alternative diagnoses, such as gonococcal arthritis, gout, rheumatoid arthritis and septic arthritis, by appropriate investigations.