A SIMPLE CLINICAL SCORING TOOL CAN BE USED TO IMPROVE PATIENT SELECTION FOR ULTRASOUND IN DIAGNOSING EARLY INFLAMMATORY ARTHRITIS

Background: Ultrasonography has been shown to be more sensitive than clinical examination in detecting clinical/subclinical synovitis and improving diagnostic certainty in early inflammatory arthritis (EIA). Local audit suggests increasing demand on ultrasound clinics to aid diagnosis in patients with suspected EIA therefore increasing waiting times. There is limited research to identify the patients most likely to benefit from an early ultrasound. Objectives (i) To evaluate the proportion of patients in whom an ultrasound resulted in a change in the pre– to post–scan diagnosis. (ii) To devise a simple scoring tool to predict patients where an ultrasound may alter the diagnosis/outcome (iii) To assess if such a scoring tool can be used prospectively in the clinical setting Methods: We conducted a retrospective analysis of the electronic records of patients attending the rheumatology-led musculoskeletal ultrasound clinic for a diagnostic scan between January and September 2017. Data on pre-test diagnosis, ultrasound findings and post-scan diagnosis was obtained. Clinical data was used to devise a scoring tool to predict variation in pre and post-scan diagnosis. Prospective data was then collected to confirm the validity of this scoring tool. Results: 200 patient records were reviewed. In 102 patients (51%), the post ultrasound scan diagnosis differed from the pre-scan diagnosis. Patients referred with polyarthralgia of uncertain cause (n=92) were the largest group in whom the post-scan diagnosis differed (64, 69.6%) as the scan was able to identify a diagnosis. Patients with a pre-scan diagnosis of osteoarthritis or fibromyalgia (n=48) were more likely to have no difference in post-scan diagnosis (40, 83.3%). We generated a score for each patient with one point given to: duration(>6 weeks), (any)tender joints, (any)swollen joints, rheumatoid factor positive, anti-citrulinated protein antibody positive, C-reactive protein(>5mg/L), erythrocyte sedimentation(>age adjusted value), early morning stiffness(>30 minutes), or radiographic erosions. 39 patients scored 0–1, and 4 patients scored 7–9. In none of these categories did the ultrasound alter the diagnosis. Among patients with a score 2–6, the ultrasound altered overall diagnosis in 26% (n=157). Scores 5 and 6 demonstrated most variation between pre and post-scan diagnoses (45%). We applied the score set prospectively and preliminary data indicates a similar distribution of results (data collection in progress). Conclusion 1. Ultrasound contributed to the overall diagnosis in over 50% of patients under investigation for EIA. 2. A simple clinical scoring tool can predict which patients the scan will make no difference to overall diagnosis. 3. Patients with scores in the middle range should be prioritised over those with very low or high scores. 4. This can be applied to improve patient selection and maximise the utility of ultrasound in EIA clinics. REFERENCES: [1] Naredo E, Bonilla G, Gamero F, Uson J, Carmona L, Laffon A. Assessment of inflammatory activity in rheumatoid arthritis: a comparative study of clinical evaluation with grey scale and power Doppler ultrasonography. Ann Rheum Dis 2005;64(3):375-81 [2] Wakefield RJ, Green MJ, Marzo-Ortega H, Conaghan PG, Gibbon WW, McGonagle D, et al. Should oligoarthritis be reclassified? Ultrasound reveals a high prevalence of subclinical disease. Ann Rheum Dis 2004;63(4):382-5. Disclosure of Interests: None declared DOI: 10.1136/annrheumdis-2019-eular.308Citation: Ann Rheum Dis, volume 78, supplement 2, year 2019, page A2032Session: Diagnostics and imaging procedures (Scientific Abstracts)