P180 External validation of the Southend GCA Probability Score (GCAPS) as a screening tool for referrals with possible GCA

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.

Does biologic survival depend on co-prescribed methotrexate dose in established rheumatoid arthritis? A real-world study

OBJECTIVE

Several seminal studies have suggested that a combination therapy of biologics with conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) improve disease outcomes in rheumatoid arthritis (RA). Hence, most guidelines reflect this practice. It has also been shown that methotrexate (MTX) at a dose of 8-10 mg/week is perhaps sufficient to achieve better outcomes in early RA. However, it is not clear whether this strategy enhances biologic retention in the patients with established RA. We present a real-world retrospective study to investigate whether csDMARD co-prescription improves biologic retention and the optimal dose to preserve such response.

MATERIALS AND METHODS

All patients prescribed biologic therapy for RA at our center between 2003 and 2017 were identified through the departmental database. They were split into five groups based on a weekly MTX dose (≤7.5 mg, 10-17.5 mg, ≥20 mg), other csDMARD prescription, or biologic monotherapy. The one-way analysis of variance model for independent values was utilized to ascertain the significance of data. The Mann-Whitney two-tailed U test was employed to determine the significance of relationship between the monotherapy group and other arms. The significance level was predefined at 0.05.

RESULTS

A total of 168 patients with 198 biologic events were included. The mean age was 59.4 years (range, 24-90 years). 78% were women. The mean disease duration was 155.6 months (range, 15-491). There was a statistically significant difference (p=0.03) in biologic retention among the five arms. Compared to monotherapy, the data remained significant for ≥20 mg MTX and csDMARD groups; however, the biologic retention in the other two MTX arms was not significant. There was no significant relationship among groups for DAS28 improvement (p=0.24).

CONCLUSION

Our results suggest that to improve biologic retention, the MTX dose should be increased to 20 mg a week or more, and, in people with MTX intolerance, csDMARDs co-presciption can be an alternative strategy. Maintenance with a low-to-moderate MTX dose can lead to poorer retention rates.

Reassessing the role of the p.(Arg304Gln) missense AIP variant in pituitary tumorigenesis

OBJECTIVE

Heterozygous germline loss-of-function variants in AIP are associated with young-onset growth hormone and/or prolactin-secreting pituitary tumours. However, the pathogenic role of the c.911G > A; p.(Arg304Gln) (R304Q) AIP variant has been controversial. Recent data from public exome/genome databases show this variant is not infrequent. The objective of this work was to reassess the pathogenicity of R304Q based on clinical, genomic, and functional assay data.

DESIGN

Data were collected on published R304Q pituitary neuroendocrine tumour cases and from International Familial Isolated Pituitary Adenoma Consortium R304Q cases (n = 38, R304Q cohort). Clinical features, population cohort frequency, computational analyses, prediction models, presence of loss-of-heterozygosity, and in vitro/in vivo functional studies were assessed and compared with data from pathogenic/likely pathogenic AIP variant patients (AIPmut cohort, n = 184).

RESULTS

Of 38 R304Q patients, 61% (23/38) had growth hormone excess, in contrast to 80% of AIPmut cohort (147/184, P < .001). R304Q cohort was older at disease onset and diagnosis than the AIPmut cohort (median [quartiles] onset: 25 y [16-35] vs 16 y [14-23], P < .001; median [quartiles] diagnosis: 36 y [24-44] vs 21 y [15-29], P < .001). R304Q is present in gnomADv2.1 (0.31%) and UK Biobank (0.16%), including three persons with homozygous R304Q. No loss-of-heterozygosity was detected in four R304Q pituitary neuroendocrine tumour samples. In silico predictions and experimental data were conflicting.

CONCLUSIONS

Evidence suggests that R304Q is not pathogenic for pituitary neuroendocrine tumour. We recommend changing this variant classification to likely benign and do not recommend pre-symptomatic genetic testing of family members or follow-up of already identified unaffected individuals with the R304Q variant.

P015 Rheumatology Patient Initiated Follow-Up (PIFU) in a busy urban district general hospital - a scoping exercise

Background/Aims

A recent report from British Society of Rheumatology (2021) highlighted severe national shortages in the rheumatology workforce. Patient Initiated Follow-Up (PIFU) is an innovative strategy for stable patients, reducing the need for “routine follow-up”. PIFU allows patients to contact their local department and organise a clinical review if they have a disease flare. In our model, a back-up appointment is made to allow ongoing future management such as drug de-escalation. PIFU has been trialled successfully in other trusts, where 20% of follow-up patients were deemed suitable. Our aim was to perform a scoping exercise to determine if PIFU would be suitable for our multi-ethnic diverse cohort in a busy urban district general hospital.

Methods

PIFU inclusion, exclusion and disease-related criteria were developed with input from departments already running PIFU. Patients were considered for PIFU if over 18 years old with a diagnosis of stable inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis, axial spondyloarthropathy) evidenced by low disease scores, no change in disease modifying drugs or steroid use in the last 12 months. Our criteria were applied retrospectively to all patients who attended consultant and registrar General Rheumatology clinics from 20th-31st January 2020. Data were collected on demographics, rheumatological diagnosis and suitability of eligible patients for PIFU.

Results

340 follow-up patients attended clinic during the 2-week period, of which 136 did not have a rheumatological condition suitable for PIFU (including osteoporosis, osteoarthritis and connective tissue disease). 42 (20.6%) of the 204 patients with eligible conditions were deemed suitable for PIFU. This represented 12.4% of our total follow-ups. In our current practice, the routine follow-up for the 42 suitable patients was arranged for a median time of 9 months (IQR: 7.75-12 months). If PIFU patients were allocated a back-up appointment at 3 years, PIFU would represent a saving of 3 routine appointments per patient over 3 years. For a full-time consultant, seeing 40 follow-ups per week, this would save 4.9 appointments per week or 198 appointments per year.

Conclusion

12.4% of our follow-up patients were deemed eligible for PIFU, which was lower than other trusts. This may be due to the low sample size or increased diversity and social complexity of our local population. Even with this lower percentage of eligible patients, PIFU may allow freeing of nearly five appointments per full-time consultant per week. PIFU may also empower patients to take ownership of their condition and enable confidence in self-management. If a PIFU service was set up locally, a robust pathway would be needed to ensure that patients could contact the department when required. The need for annual disease review would also need to be considered using primary care or IT solutions.

Disclosure

N. Mothojakan: None. L. St.Aimee: None. C. Quieros: None. N. Horwood: None. S. Levy: None. R. Sathananthan: None.