P195 Use of the Giant Cell Arteritis Score (GCAPS) in a district general hospital

Abstract

Abstract Background/Aims The Giant Cell Arteritis Score (GCAPS) was developed by the specialist team in Southend, Essex, UK in 2018. It is a clinically focused tool to aid diagnosis of GCA by providing a pre-test probability, with a threshold of greater than 9 denoting higher risk of GCA requiring further diagnostic testing. So far, it has been validated externally in patients in 2 centres. In all cases, scoring was completed by a rheumatology consultant. We are keen to validate it in our setting, a district general hospital without rapid access to vascular ultrasound, to determine whether it was a valid and reliable tool for assessing which patients required temporal artery biopsy and which patients could rapidly taper steroids following a negative result. We also aimed to see whether scoring could be completed by clinicians other than rheumatology consultants. Methods We retrospectively applied the GCAPS score to all patients referred as possible GCA to our service between November 2021 - April 2022 by reviewing clinical notes. A medical student (TS) with no prior experience was trained to use the score, with scoring independently repeated by a rheumatology consultant (RW). Results 34 patient records were reviewed. 14 (41%) were male, mean age 70.5 (range 49 - 89). 6 had biopsy confirmed GCA, 7 had a clinical diagnosis of GCA and 21 had a low probability of GCA. All 13 patients with biopsy confirmed or clinical GCA were scored > 9 by both assessors. There was GCAPS agreement in 7/34 patients (21%). Of 27 patients with differing scores, TS gave a higher score in 17 (50%). In 4 patients, there was a difference in probability threshold. In all cases, the patient was scored more highly by TS. None of the patients had a final diagnosis of GCA. 5 patients had known GCA and a relapse was being questioned. 2/5 had a flare - one clinical and one biopsy proven. The GCAPS was >9 in both patients. There were no missing data. Conclusion We have demonstrated that it is possible to train someone without prior experience to use GCAPS. There were differences in probability threshold in 4 patients, with the less experienced assessor tending to overscore. The GCAPS is applicable in our non-specialised centre and is feasible to use as evidenced by the lack of missing data. No patients with a GCAPS under 9 had a final diagnosis of GCA. This good negative predictive value is in keeping with previously published data. In a small patient number, the GCAPS threshold remained valid in distinguishing relapse. We feel GCAPS has two roles. It can be used to triage who needs review in rheumatology clinic. It can also be used in rheumatology clinic to determine who requires temporal artery biopsy. Disclosure R. Waller: None. S. Carty: None. T. Schmitt: None.