Annual TB Testing of Health Care Workers Not Cost Effective

Routine annual tuberculosis (TB) screening of health care workers is no longer cost effective, according to a study published May 17 in BMC Medicine. The incidence of TB is at an all-time low in the United States and previous studies have shown that health care workers’ rates of active TB is the same as the general population. The results of the new modeling study led the authors to say that annual screening needs to be reconsidered.

The authors created a decision analysis model to simulate a hypothetical group of 1,000 workers with negative baseline tests. The model considered their duties, tuberculosis exposure, testing scenarios, and treatment. The model used two tests—the tuberculin skin test (TST) and QuantiFERON-TB-Gold In-Tube (QFT; Qiagen). Three screening strategies were compared, including annual screening, targeted screening, where workers with high-risk duties (e.g., respiratory therapy) were tested yearly and other workers only after exposure, and post exposure-only screening only. Patient care duties were characterized as high-risk (1 percent annual risk of infection) or standard patient care duties (0.3 percent). An alternate higher-risk scenario was created with annual risks of infection of 3 percent and 1 percent, respectively. Costs, morbidity, quality-adjusted survival, and mortality were modeled over 20 years.

Over the modeling period, annual screening with TST yielded an expected 2.68 active tuberculosis cases per 1,000 workers, versus 2.83 for targeted screening, and 3.03 for post-exposure screening only. As might be expected, the least costly screening strategy was post-exposure screening only with the TST, while annual screening with the QFT was the most costly.

Annual TST screening had an incremental cost of $1,717,539 per additional case prevented versus targeted TST screening, which cost an incremental $426,678 per additional case prevented, versus post-exposure TST screening only. In the higher-risk scenario, annual TST cost $426,678 per additional case prevented versus the targeted TST strategy, which cost an estimated $52,552 per additional case prevented, versus post-exposure TST screening only. In all cases, QFT had no or limited added benefit, but was more expensive than TST.

“Annual worker screening may no longer be appropriate in most settings, and reconsideration of this longstanding recommendation may be warranted,” write the authors led by Guillaume Mullie, from McGill University in Canada. “The resources currently allocated to routine TB testing for HCWs may be more productively used for other TB prevention activities.”

Takeaway: Given that health care workers in the United States are exposed to fewer patients with tuberculosis, annual screening is no longer cost effective.