Background PR is an unusual arthritis characterised by brief, self-limiting attacks of synovitis usually affecting one joint at a time with outcomes including transformation to persistent inflammatory rheumatic disease, usually rheumatoid arthritis (RA), continuation of PR and spontaneous remission. Seropositivity for rheumatoid factor (RF) or ACPA may predict transformation to RA. We examined the experience of PR in a large UK teaching hospital rheumatology department using data collected routinely at outpatient encounters. The NCR records a primary rheumatology diagnosis, demographic data, administrative details (type of consultation, grade of clinician and outcome) for every rheumatology consultation. Between March 2016 and February 2017 19 832 clinical encounters were logged forming the basis of this study.

Objectives To identify the burden of PR in a large UK teaching hospital and its management in a real world setting.

Methods PR patients were extracted from the NCR and their electronic record (Bloods/Radiology/Clinic letters) analysed for any change in diagnosis (prior to or following PR diagnosis), treatments prescribed, serological status and radiological findings. In the subgroup whose diagnosis changed, a separate analysis to look at predictive factors was carried out.

Results 101 patients (149 attendances) were analysed (24 new patient appointments, 125 follow ups). The female:male ratio was 2.16, mean age 53.5. Over half were between 40–59. 31 new diagnoses of PR were made in the study period. The NCR prevalence of PR was 1%. Duration of PR in previously diagnosed patients was a mean of 4 years. The diagnosis was changed in 13 PR patients (to RA in 9). Serological status is shown below:

Plain radiographs were available for 88 patients (hands- 69, feet- 54). Erosions were noted once (RA was then diagnosed). Synovitis was detected in 10 of 25 patients who underwent ultrasound and in 2 of 18 patients who underwent small joint MRI. 63 patients were on DMARDs, most often HCQ,⁴³ 9 received dual DMARD therapy. DMARD therapy was more frequent in sero-positive patients. PR patients later diagnosed as RA were older (64.9 vs 53.5 years) and more commonly seropositive (6 being dual antibody positive) with similar gender ratio (2:1 F:M). The duration of PR diagnosis ranged from 6 months to 10 years (average 4.2).

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Abstract SAT0092 – Figure 1

PR patients by age

Conclusions PR accounted for 1% of all patients on the NCR with 10% of patient’s having their diagnosis changed in the study period. RA patients on the NCR numbered 2292, making the RA:PR ratio 22.7:1. Approximately half of PR patients were RF/ACPA positive or both with over half the PR population on DMARD treatment, most often HCQ. PR patients developing RA were older and ACPA/RF positivity was more common. Although a third PR patients who later developed RA did so within 2 years, the majority took longer with some diagnosed as RA over 5 years later suggesting PR patients, especially if seropositive, should be followed long term. Two year follow up will be available from March 2018.

Acknowledgements Thanks to: Nottingham Circle secretarial and IT staff and Beth Rawson, librarian at Derby Hospital.

Disclosure of Interest None declared