Low clinical value in repeat latent TB tests in patients taking biologics

TLANTA — Repeat, routine testing for latent tuberculosis infection among patients receiving biologics is both costly and of low clinical value, according to findings presented at the 2019 ACR/ARP Annual Meeting.

“The CDC in 2010 recommended that the QuantiFERON TB can essentially replace the TST in all situations where a TB screening is required,” Urmi Khanna, MD, of the Cleveland Clinic, told attendees. “So, how frequently should we screen our patients who are on biologics for latent TB infection? All patients should definitely be screened at baseline, but the recommendations for repeat TB screening vary. The National Psoriasis Foundation recommends annual repeat screening in all patients taking biologics; however, the CDC and the American College of Rheumatology recommend annual testing only in patients with risk factors for tuberculosis.”

“These risk factors, as outlined by the CDC, are immigrants, persons who travel to endemic areas, people who have come in contact with infected persons, workers in special situations like correctional facilities, nursing homes and homeless shelters, as well as immunosuppressed individuals,” she added. “Another aspect that could affect the frequency of latent TB infection screening is that recommendations for annual screening have been incorporated into Medicare merit-based incentive payment systems and will impact physician reimbursement. Based on this, we expect that more and more physicians will adopt this practice of annual latent TB infection screening in all patients with biologics.”

To assess the value and cost-effectiveness of repeated latent tuberculosis screening among patients treated with biologics, and to determine risk factors in those who convert from negative to positive QuantiFERON test results when taking biologics, Khanna and colleagues retrospectively reviewed data from a tertiary care center between August 2007 and March 2019. The researchers analyzed latent tuberculosis screening results of 10,914 patients treated with biologics, collecting demographic information, the primary diagnosis, biologics used, length of therapy, number of QuantiFERON tests and those test results for each patient.

Among the patients treated with biologics, 5,212 had at least one repeat of QuantiFERON test result following biologic initiation, and were included in the final analysis. The most common diagnoses among the included participants were inflammatory bowel disease, representing 31% of patients, rheumatoid arthritis, at 29%, and psoriatic arthritis, with 25%.

According to the researchers, 87.5% of patients demonstrated negative QuantiFERON tests, while 9.2% had one or more indeterminate result and 3.3% had more than one positive result. Among those with positive tests, 61 converted from a negative to a positive QuantiFERON test after starting biologics. Just one case of active tuberculosis was found in the entire study cohort. In addition, this patient had a significant risk factor in the due to recent travel to a tuberculosis-endemic area, the researchers wrote.

“We found only one case of active tuberculosis in our entire study cohort of 5,212 patients,” Khanna said. “So, based on this study, we could like to propose that in low-incidence TB regions such as the United States, repeat latent TB infection testing in patients on biologic therapies should be focused on patients who have new risk factors for TB infection since their last screening.” – by Jason Laday

Khanna U. Utility of repeat latent tuberculosis testing in patient taking biologics. Presented at: American College of Rheumatology/Association of Rheumatology Professionals Annual Meeting; Nov. 9-13, 2019; Atlanta.

Source: Healio

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By Healio

Published: Nov. 15, 2019, 1:44 p.m.

Last updated: Nov. 25, 2019, 1:46 p.m.

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