Background
We run a rheumatologist-led, ultrasound-driven giant cell arteritis (GCA) fast track pathway (FTP). Currently, no specific referral criteria are required. Sensitive referral criteria are now needed to safely reduce referrals, which have risen year-on-year (92 in Year 3, 84% greater than Year 1).
Methods
The following were collected for all patients referred to our GCA-FTP from 1/4/2018-31/3/2019 (Year 3): Final diagnosis of imaging/biopsy confirmed-GCA, unconfirmed clinical-GCA or not-GCA using the electronic patient record to September 2019; Rheumatologist-determined clinical probability of GCA (low, moderate, high) before imaging/biopsy; Presence of ≥ 3 ACR 1990 GCA Classification Criteria (biopsy excluded, adapted to increase sensitivity, see table); Presence of Southend GCAPS≥10 (Based on our clinical experience, polymyalgic symptoms were also counted if patients had recently taken prednisolone for PMR).
Results
88 consecutive patients were analysed (total 92: 2 missing data; 2 passed through twice). 25/88 (27%) were diagnosed with GCA 24 were imaging/biopsy confirmed. The single patient with unconfirmed clinical-GCA had high clinical probability, indeterminate ultrasound and biopsy after >1-week glucocorticoid. GCA patients were mean age 77.3y (range 63-94), 76% female, all White, with mean GCAPS 15.3 (range 10-25).
Our adaptations of the ACR criteria increased ACR-criteria sensitivity: 24% GCA patients had new generalised headache and 16% had ESR<50, but CRP>10. 14% referrals were non-White, although GCA is rare in this group. GCAPS was based on a largely White population. If GCAPS did not remove 3 points for alternative diagnoses, then 5 additional non-White patients would have scored ≥10.
Conclusion
This study externally validates GCAPS≥10 as a screening tool for referrals with possible GCA. It captured all GCA patients and screened out 44% referrals. For this indication, it performed better than a consultant rheumatologist. Despite adaptations to improve sensitivity, ACR criteria missed a quarter of cases. To improve GCAPS specificity when scored by a non-rheumatologist, GCAPS should be adapted to reflect the low likelihood of GCA in non-Whites. We plan to only accept patients with GCAPS≥10, where 3 points are removed for non-Whites if not already removed for alternative diagnoses. We predict referrals will reduce but anticipate referrers will need education to limit over-scoring.
Disclosures
V. Quick None. M. Hughes None. N. Mothojakan None. D. Fishman None.
European Journal of Rheumatology (Eur J Rheumatol) is an international, open access peer reviewed journal committed to promoting the highest standards of scientific exchange and education. The journal is published quarterly on January, April, July and October. The aim of the European Journal of Rheumatology is to cover various aspects of rheumatology for its readers, encompassing the spectrum of diseases with arthritis, musculoskeletal conditions, autoinflammatory diseases, connective tissue disorders, osteoporosis, translational research, the latest therapies and treatment programs. European Journal of Rheumatology publishes original articles, invited reviews, case based reviews, letters to the editor and images in rheumatology. The publication language of the journal is English.
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