Table 3

Performance of the referral strategies in the Leiden SPACE cohort using diagnosis by the rheumatologist as the external standard

107 diagnosed with axSpA 154 not diagnosed with axSpA		Correctly referred/correctly not referred patients
107 diagnosed with axSpA 154 not diagnosed with axSpA		Patients diagnosed with axSpA by the rheumatologist referred by strategies (correctly referred)		Patients not diagnosed with axSpA by the rheumatologist not referred by strategies (correctly not referred)
Strategy	LR+	N out of 107	Sensitivity	N out of 154	Specificity
Brandt I	1.10	105	0.98	17	0.11
Brandt II	1.23	99	0.93	38	0.25
Brandt III	1.86	79	0.74	93	0.60
Hermann	1.19	89	0.83	46	0.30
MASTER	2.68	69	0.64	117	0.76
Braun IBP	1.29	84	0.79	60	0.39
RADAR	2.12	84	0.79	97	0.63
RADAR 2/3	2.51	47	0.44	127	0.82
Braun two-step	1.83	80	0.75	91	0.59
Braun two-step alt.	2.10	70	0.65	106	0.69
CaFaSpA ≥1pt	1.25	93	0.87	47	0.31
CaFaSpA ≥2pt	1.98	55	0.51	114	0.74
ASAS	1.20	105	0.98	28	0.18

alt, alternative; ASAS, Assessment in SpondyloArthritis international Society; axSpA, axial spondyloarthritis; IBP, inflammatory back pain; LR+, positive likelihood ratio; RADAR, Recognising and Diagnosing Ankylosing Spondylitis Reliably; SPACE, Spondyloarthritis Caught Early.