From the Guidelines

Elevated Rheumatoid Factor (RF) is a serological marker that may indicate autoimmune disorders, such as rheumatoid arthritis 1.

In patients with elevated RF, treatment with disease-modifying antirheumatic drugs (DMARDs) such as methotrexate (10-20 mg/week) or hydroxychloroquine (200-400 mg/day) may be initiated to reduce inflammation and slow disease progression 1.
Additionally, nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (600-1200 mg/day) or naproxen (250-500 mg/day) may be prescribed for symptom management, with treatment duration and dosage adjusted based on individual patient response and disease activity.
Elevated RF is also a risk factor for interstitial lung disease (ILD) in patients with rheumatoid arthritis, and vigilant monitoring is necessary to detect ILD at an early stage 1.
In patients with RA-ILD, antifibrotic treatment such as nintedanib may be considered to slow down disease progression 1.

The Disease Activity Score using 28 joint counts (DAS28) is recommended for assessing disease activity and treatment response 1.
Composite measures of disease activity, such as the Simplified Disease Activity Index (SDAI) and Clinical Disease Activity Index (CDAI), can provide a more stringent definition of disease activity 1.
Regular evaluation of disease activity, including patient-reported outcomes and physical examination, is necessary to adjust treatment and achieve optimal outcomes 1.

From the Research

An elevated Rheumatoid Factor (RF) is associated with increased disease activity, radiographic progression, and the presence of extraarticular manifestations in Rheumatoid Arthritis (RA) patients 2
RF is observed in 80-85% of patients with RA, with a sensitivity of 50-90% and specificity of 50-95% 2
Elevated serum level of RF has been linked to poor prognosis and early erosions of the joints 2, 3
RF, in combination with other biomarkers such as C-reactive protein (CRP) and anti-cyclic citrullinated protein (Anti-CCP), can be used to predict bone erosion and cartilage destruction in RA patients 3
RF is not associated with joint damage but correlates with ultrasound-detected bone erosion 3

RF is often used in conjunction with other biomarkers, such as Anti-CCP, to aid in the diagnosis and monitoring of RA 4, 5
The combination of high 14-3-3η protein with RF and CRP can improve the prediction of rapid erosion progression (REP) in RA patients 3
RF has been shown to correlate with disease activity and positively correlate with RA duration, disease activity, and positive Anti-CCP 3

Elevated RF levels can be used as a diagnostic marker for RA, particularly in combination with other biomarkers 2, 3
RF levels can also be used to monitor disease progression and response to treatment in RA patients 5, 3
The use of RF as a biomarker can help clinicians make informed decisions about treatment and prognosis in RA patients 3