Background/Purpose:

Arthralgia in patients who are seropositive for rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA) is a precursor to rheumatoid arthritis (RA) in some but not all patients. The factors which influence progression and outcomes in these patients remain to be fully defined. The aim of this study was to evaluate outcome and prognostic factors in a consecutive cohort of patients with seropositive arthralgia undergoing arthroscopy.

Methods:

We performed a prospective study of consecutive patients seropositive for RF and/or ACPA, with arthralgia, presenting to our outpatient clinic. Demographic and clinical measures were collected and synovial biopsy was performed by needle arthroscopy to score macroscopic and microscopic changes. The degree of synovitis and vascularity were recorded on a 0–100-mm visual analog scale, and chondropathy on a semi-quantitative scale from 0-3. Patients were then followed up at 3 monthly intervals and the time of diagnosis recorded. Mann-Whitney U test was used to compare groups. Spearman’s Rank Correlation Coefficient was used to assess for associations between biometrics and demographic and clinical markers. GraphPad Prism Version 7 and IBM SPSS Statistics Version 24 were used for data analysis.

Results:

33 patients were recruited. Mean (SD) age was 54 (12) years. 22 (67%) were female. 27 (82%) were positive for RF and 30 (91%) for ACPA with 24 (73%) dual positive. Mean (SD) follow-up was 29 (10) months. Baseline characteristics are shown in Table 1. Final diagnosis was RA in 24 (73%), psoriatic arthritis in 2 (6%), connective tissue disease in 1 (3%), calcium pyrophosphate arthritis in 1 (3%), and remained seropositive arthralgia in 5 (15%). Baseline CRP was significantly higher in patients who developed rheumatoid arthritis than those who remained seropositive arthralgia, mean (SD) 9.63 (16.63) vs 1.40 (0.55) mg/dL (p=0.005). CRP was elevated in 9/24 RA patients (range 1-64 mg/dL), and 0/5 who remained seropositive arthralgia (range 1-2 mg/dL). Macroscopic synovitis and vascularity were both significantly higher in those who developed RA than in those who remained arthralgia only, mean (SD) 60 (25) vs 28 (13) mm (p=0.009) and mean (SD) 56 (26) vs 26 (13) mm (p=0.012) respectively. Baseline DAS28-CRP, tender joint count, swollen joint count, and patient global assessment were not different between the groups. Baseline synovial cell immunophenotyping did not predict final diagnosis.

Conclusion:

The majority of seropositive arthralgia patients developed RA. Elevated baseline CRP and macroscopic synovitis and vascularity scores at arthroscopy predict the future development of RA.

Table 1: Baseline Characteristics of 33 Patients with Seropositive Arthralgia

Data expressed as mean (SD) unless otherwise specified.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/prediction-of-future-development-of-rheumatoid-arthritis-in-patients-with-seropositive-arthralgia/