Rheumatoid Arthritis Onset Earlier, More Frequent in Hands Than Feet

Patients with clinically suspect arthralgia (CSA) progressing to rheumatoid arthritis (RA) more frequently develop earlier joint involvement in the hands vs feet, according to results of a longitudinal study published in RMD Open.

Understanding of joint involvement in the earliest phases of RA development may lead to greater understanding of the overall trajectory of arthritic disease. Thus, researchers aimed to determine whether RA joint involvement begins in the hands or feet and whether functional disabilities at CSA onset are predictive of progression to RA.

Data were taken from the Leiden CSA cohort, comprised of patients with CSA who developed inflammatory arthritis (IA). Patients were followed for 2 years. Functional disabilities were assessed via the Health Assessment Questionnaire Disability Index (HAQ) at baseline, 4, 12, and 24 months. Cox regression was used to evaluate associations between disabilities at CSA presentation and future IA development.

A total of 600 patients were included in the analysis. Of these, 37% reported tender hand and foot joints, 8% reported only tender foot joints, and 42% reported only tender hand joints. Complaints of joint tenderness were more likely to begin in the upper extremities (67%) vs simultaneous upper and lower extremities (17%) and lower extremities only (10%).

At the time of progression to IA, more patients developed hand (81%) vs foot (42%) disabilities.

While there was an increase in both hand and foot disabilities during IA development, (+0.25 and +0.29 units/year, respectively), hand disabilities were more severe during this period (mean difference over time, 0.41 units; 95% CI, 0.28-0.55; P <.001).

Similar to functional disabilities, subclinical joint inflammation and tender joints occurred earlier in hands than feet.

Among all components of the HAQ analyzed, only difficulty with hand functioning while dressing was identified as an independent predictor for IA development (hazard ratio, 2.2; 95% CI, 1.4-3.5; P =.001).

This study was limited by a maximum of only 3 observations per patient on disabilities, joint tenderness, and imaging data. Additionally, calculations were based on the assumption that the relationship between symptoms and time to IA development were similar among all patients with CSA. The investigators note future research would benefit from a focus on large joint involvement in RA development. 

“These results may influence future research and clinical practice that could use hand assessments to risk stratify individual with joint symptoms who are considered at-risk

for future RA,” the investigators concluded.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.