Infections during low-dose methotrexate treatment in rheumatoid arthritis

Area of Science:

• Rheumatology
• Infectious Diseases
• Pharmacology

Background:

• Rheumatoid arthritis (RA) treatment often involves disease-modifying antirheumatic drugs (DMARDs).
• Methotrexate (MTX) is a common first-line DMARD for RA.
• Understanding infection risks associated with MTX is crucial for patient safety.

Purpose of the Study:

• To investigate infection rates in rheumatoid arthritis (RA) patients treated with low-dose methotrexate (MTX).
• To compare MTX with azathioprine (AZA) regarding infection risk.
• To review literature on therapy-related opportunistic infections in RA and related conditions.

Main Methods:

• A 6-year open prospective study of RA patients on low-dose MTX.
• A 12-month randomized double-blind trial comparing MTX and AZA, followed by a 3-year open study.
• Literature review for infections in RA, psoriasis, and psoriatic arthropathy patients on MTX and other DMARDs.

Main Results:

• Infection rates were higher in severe RA patients compared to moderate RA patients on MTX.
• Most infections occurred within the first 1.5 years of MTX treatment.
• No significant difference in infection rates between MTX and AZA in the comparative trial.
• Opportunistic infections are increasingly reported with MTX in RA and related conditions.

Conclusions:

• The initial treatment period with MTX poses the highest risk for infections in RA patients.
• Severe RA patients may experience a greater number of infections during MTX therapy.
• Opportunistic infections associated with MTX are a significant concern and not limited to the early treatment phase.