Table 1

Summary of studies included in the systematic literature review

Author (year)	Country	Referring physician	Strategy	No. of patients referred	% axSpA
Brandt (2007)	Germany	GP	CLBP (>3 months) and onset <45 years plus ≥1 of: IBP, HLA-B27+, sacroiliitis	350	45.4
Hermann (2009)	Austria	GP and orthopaedic surgeon	IBP (Calin criteria, >3 months) <45 years	92	32.6
Braun (2011)	Germany	Orthopaedic surgeon	CBP (>2 months and <10 years) and onset <45 years with inflammatory character a/o good response to NSAIDs according to computer algorithm	322	35.1
Poddubnyy (2011)	Germany	GP and orthopaedic surgeon	Strategy 1: CBP (>3 months) and onset <45 years plus ≥1 of: IBP, HLA-B27+, sacroiliitis on imaging	Strat 1: 318	Strat 1: 41.8
Poddubnyy (2011)	Germany	GP and orthopaedic surgeon	Strategy 2: CBP (>3 months) and onset <45 years plus ≥2 of: IBP, HLA-B27+, sacroiliitis on imaging, good response on NSAIDs, positive family history of SpA	Strat 2: 242	Strat 2: 36.8
Sieper (2013)	International	GP and other physicians	Strategy 1: CBP (>3 months) and onset <45 years plus ≥1 of: IBP, HLA-B27, sacroiliitis on imaging	Strat 1: 504	Strat 1: 35.6
Sieper (2013)	International	GP and other physicians	Strategy 2: CBP (>3 months) and onset <45 years plus ≥2 of: IBP, HLA-B27, sacroiliitis on imaging, good response on NSAIDs, positive family history of SpA, presence of EAM	Strat 2: 568	Strat 2: 39.8
Van den Berg (2013)	Netherlands	GP and other physicians	CBP (>3 months and <2 years) and onset <45 years	157	41.4
Brandt (EULAR 2012)	Germany	None (self-referral)	CBP, online questionnaire using diagnostic algorithm	97	14.4
Weel (EULAR 2012)	Netherlands	GP	CLBP, identified from GP records	364	21.5

axSpA, axial spondyloarthritis; CBP, chronic back pain; CLBP, chronic low back pain; EAM, extra-articular manifestation; EULAR, European League Against Rheumatism; GP, general practitioner; HLA, human leucocyte antigen; IBP, inflammatory back pain; NSAIDs, non-steroidal anti-inflammatory drugs; SpA, spondyloarthritis.