Assessment of PPD Conversion Rate in Patients Receiving Tumor Necrosis Factor-alpha Inhibitor Drugs

Area of Science:

• Immunology
• Infectious Diseases
• Rheumatology

Background:

• Tumor necrosis factor-alpha (TNF-α) inhibitors are crucial for treating rheumatologic diseases.
• These therapies may elevate the risk of tuberculosis (TB) infection or reactivation.
• Purified protein derivative (PPD) conversion signals latent TB in immunosuppressed individuals.

Purpose of the Study:

• To determine the rate of PPD conversion in patients undergoing anti-TNF therapy.
• To identify factors associated with PPD conversion during anti-TNF treatment.

Main Methods:

• A prospective study enrolled adults with rheumatologic conditions starting anti-TNF therapy.
• Baseline PPD testing was conducted, with repeat testing one year later.
• Exclusion criteria included prior TB, previous anti-TNF use, or baseline PPD positivity.

Main Results:

• Ten percent (6/60) of patients exhibited PPD conversion after one year.
• Psoriatic arthritis was significantly associated with PPD conversion (P=0.03).
• No significant associations were found with age, sex, disease duration, or concomitant medications.

Conclusions:

• Anti-TNF therapy is associated with a 10% rate of new latent TB infection (PPD conversion).
• Psoriatic arthritis is a risk factor for PPD conversion.
• Annual TB screening is recommended for anti-TNF recipients, especially in high-prevalence areas.