Background/Purpose:

Tumor necrosis factor alpha (TNF-α) inhibitors are used to reduce the inflammatory process in many autoimmune diseases. Due to the risk of reactivation of latent tuberculosis, screening for latent infection with either purified protein derivative (PPD) skin testing or gamma interferon (GIF) release assay is necessary prior to initiation of treatment. Recommendations for subsequent testing while on TNF-α inhibitors vary, and there is a lack of data regarding the incidence of screening test conversion for patients on TNF-α inhibitors.

Methods:

Between March 29, 2010 and October 19, 2016, patients over the age of 18 who had had an encounter with a rheumatologist at one of the University of Rochester Medical Center rheumatology practice clinics were identified through a search of our electronic medical record. Our physicians provide care for an estimated 60% of the patients in the referral catchment population of approximately 1.1 million residents (including 5 suburban and agricultural counties and a medium sized city of 210,000). The charts of those who had been prescribed a TNF-α inhibitor (adalimumab, certolizumab, etanercept, golimumab, or infliximab) and who had been identified by ICD coding for positive PPD or GIF release assay testing, were reviewed.

Results:

Of the 2807 rheumatology clinic patients treated with TNF-α inhibitors, 89 cases (2.9%) of latent tuberculosis were identified and verified by chart review to have a confirmed positive PPD reading or GIF release assay. 25 (28.1%) of these cases were identified after the initiation of a TNF-α inhibitor as new converters. The rate of PPD or GIF-release assay conversion with TNF-α inhibitor use amongst our cohort is 0.89% (25 of 2807 patients).

Conclusion:

We documented a 0.89% PPD/GIF conversion rate in our patients on TNF-α inhibitors. Our data suggests that continued screening of patients maintained on TNF-α inhibitor therapy will improve identification of these patients unknowingly exposed to mycobacterial infection.

« Back to 2018 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/incidence-of-conversion-of-screening-tests-for-m-tuberculosis-ppd-gif-release-assay-in-a-metropolitan-cohort-of-patients-treated-with-tnf-%ce%b1-inhibitors/