Table 2.

Sensitivity, specificity, PPV and NPV of enthesitis by PDUS for meeting ASAS classification criteria for axial spondyloarthritis, in the DESIR cohort

PDUS performedN=402	PDUS enthesitisN (%)	Sensitivity(IC 95%)	Specificity(IC 95%)	PPV(IC 95%)	NPV(IC 95%)
PDUS enthesitis at any site	58(14.4%)	13.9%(9.9 to 17.9)	83.5%(76.5 to 90.4)	69%(57 to 80.9)	26.8%(22.1 to 31.5)
Achille’s PDUS enthesitis	15(3.7%)	4%(1.8 to 6.4)	97%(94.2 to 100)	80%(59.7 to 100)	28%(23.2 to 32.2)
Patellar ligaments PDUS enthesitis	36(9%)	8%(5.1 to 11.5)	89%(83.1 to 94.8)	67%(51.2 to 82.1)	27%(22.2 to 31.4)
Lateral epicondyle PDUS enthesitis	20(5%)	5%(2.4 to 7.3)	94%(90.2 to 98.7)	70%(49.9 to 90.1)	27%(22.8 to 31.8)

The sensitivity and specificity of PDUS-defined enthesitis were calculated on the 402 patients who underwent PDUS, using classification as axial spondyloarthritis according to the ASAS criteria as the reference standard (n=288 patients met these criteria).

ASAS, Assessment of SpondyloArthritis international Society; DESIR, DEvenir des Spondylarthropathies Indifférenciées Récentes; NPV, negative predictive value; PDUS, power Doppler ultrasonography; PPV, positive predictive value.