POS0337 SOUTHEND PRE-TEST PROBABILITY SCORE AND HALO SCORE AS MARKERS FOR DIAGNOSIS AND MONITORING OF GCA: EARLY RESULTS FROM THE PROSPECTIVE HAS-GCA STUDY

Background: EULAR recommends doppler ultrasound (US) as the first line imaging in patients with Giant Cell Arteritis (GCA) suspect. Traditionally, US non-compressive halo sign has been used for diagnosis but prospective studies on response and disease monitoring are lacking Objectives: The HAS GCA study objective of prospectively assessing role diagnosis, prognosis newly diagnosed GCA. We report early baseline up to month 3 data our current recruitment a that suffered disruption from pandemic Methods: (IRAS#264294) is an ongoing, prospective, multicentre recruiting referrals suspected fast track clinics. recruit 270 patients, including 68 patients. Based Southend clinical pre-test probability score (SPTPS) 1 , were stratified low, intermediate high risk categories 2 . Temporal axillary Halo Scores calculated thickness extent bilateral temporal arteries, parietal frontal branches arteries. These individual scores summed (TA Score x1 plus; AA x3) generate Total (THS) Mann Whitney U test Fisher’s exact compare features between controls. Wilcoxon signed rank was evaluate at months Sensitivity (Sn) Specificity (Sp) calculated, where applicable. P value <0.05 statistically significant Results: Ninety-three (29 GCA, 64 controls) have recruited thus far: 18 completed 3-month follow assessment; 4 lost (2 died, withdrew consent due pandemic). Demographics, features, results shown (Table 1). Table 1. Baseline (n=29) Controls (n=64) P-value Age, median (IQR) 75 (71-80) 67 (61.25 – 75.0) 0.001 Female, n (%) 15 (42) 50 (78) 0.01 SPTPS category, Low 0 (0) 31 (48) <0.001 Intermediate 7 (24) 25 (39) 0.24 High 22 (76) 8 (13) (HS), (range) artery HS 10 (1-21) (0-9) Axillary 12 (0-18) 6 21 (2-38) (0-19) Clinical headache (72) 40 (63) 0.48 Scalp tenderness 17 (59) 0.38 Jaw claudication 19 (66) (6) PMR symptoms 16 (55) (9) Constitutional (28) 0.006 Visual disturbance (62) 38 Vision loss 0.03 Among 23 had cranial, large-vessel mixed phenotypes (cranial plus large vessel) disease. (66%) polymyalgic (55%) dominant Median age years (42% females) controls (78% females). by (0% vs 48%; Sn-undefined, Sp-97), (24% 39%; Sn-100, Sp-100) (76% 13%; Sn-95, Sp-88). Optimal cut-off point ?12 (Sn-93, Sp-86); ?10 (Sn-100 & Sp-69). THS TAHS ?5 (Sn-90, Sp-98), AAHS ?11 (Sn-55, Sp-80), ?18 (Sn-72%, Sp-98%). who 3-months up, TAHS, reduced 2.5, 10, respectively (Figure Conclusion: Along SPTPS, successfully discriminates non mimics. effective showing may be useful marker monitor activity. References: [1]Laskou F et al. A aid giant cell arteritis. Clin Exp Rheumatol. 2019 [2]Sebastian Probability-based algorithm using additional tests fast-track clinic. RMD Open. 2020 [3]Sebastian (temporal artery, its artery) diagnostic, prognostic tool (GCA). BMC Disclosure Interests: Alwin Sebastian: None declared, Alessandro Tomelleri: Abdul Kayani: Mohammad Tariq: Diana Prieto-Peña: Sue Inness: Jo Jackson: Kornelis van der Geest Speakers bureau: Roche, Bhaskar Dasgupta GSK, BMS, Sanofi, Abbie, Grant/research support from: Roche