Functional limitations in the phase of clinically suspect arthralgia are as serious as in early clinical arthritis; a longitudinal study.

INTRODUCTION: A phase of arthralgia may precede the emergence of rheumatoid arthritis (RA). Although several studies have focused on biomarkers, the relevance of this phase for patients is less studied. It is unknown if patients already have functional limitations and if this is correlated to the extent of subclinical inflammation. Therefore, we assessed functional disability in patients with clinically suspect arthralgia (CSA), its association with MRI-detected subclinical inflammation and its course during progression to clinical arthritis.

METHODS: From April 2012 to March 2015, 241 patients had arthralgia for <1 year and were, based on clinical presentation, considered at risk for RA by their rheumatologists. At baseline, Health Assessment Questionnaire (HAQ) scores were determined and unilateral 1.5 T MRI of metacarpophalangeal, wrist and metatarsophalangeal joints were made. Presence of MRI-detected subclinical inflammation was assessed by summing synovitis, tenosynovitis and bone marrow oedema scores (range 0-189). Patients were followed on arthritis development and HAQ scores were repeated when clinical arthritis had developed.

RESULTS: The median HAQ score at presentation with CSA was 0.50. Higher MRI-inflammation scores were associated with higher HAQ scores (β=0.017, 95% CI=0.004 to 0.030). During median 103 weeks follow-up, 44 patients progressed to clinical arthritis. HAQ scores ≥1.0 were associated with arthritis development (HR=2.50, 95% CI=1.03 to 6.10). Within converters, median HAQ scores did not increase from presentation with CSA to arthritis development (0.88 and 0.75, p=0.36).

CONCLUSIONS: HAQ scores ≥1.0 at presentation were associated with the development of clinical arthritis. Functional limitations in the prearthritis phase of CSA were as serious as in the early clinical phase, demonstrating the relevance of CSA from patients' perspectives.