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Experts suggest urine-based TB screening for all patients with HIV

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January 26, 2019

Krishna P. Reddy, MD
Krishna P. Reddy

In resource-limited settings, urine-based tuberculosis screening of all hospitalized patients with HIV is a cost-effective strategy that could increase their life expectancy, according to a microsimulation modelling study published in The Lancet Global Health.

“Tuberculosis is the leading killer of people with HIV worldwide,” Krishna P. Reddy, MD, assistant professor of Medicine at Harvard Medical School and pulmonologist and critical care physician at Massachusetts General Hospital, told Infectious Disease News. “Screening all hospitalized patients with HIV for tuberculosis using urine tests would increase their life expectancy and be cost-effective, with a modest increase in health care expenses. It is a wise investment. The urine [lipoarabinomannan (LAM)] test, in particular, is inexpensive and easy, and it identifies many tuberculosis cases that otherwise would have been missed.”

Currently, WHO recommends Mycoplasma tuberculosis LAM (TB-LAM) testing only for hospitalized patients with HIV whose CD4 counts are 100 cells/L or lower. Moreover, the patient must present with TB symptoms.

In the modelling study, the researchers compared two TB screening strategies irrespective of symptoms among hospitalized patients with HIV in Malawi and South Africa. These included use of Cepheid’s GeneXpert assay to test for M. tuberculosis and rifampin resistance in sputum samples — the current standard of care — and a strategy that combined the sputum test with the urine TB-LAM assay and a concentrated urine Xpert assay.

“We adapted a mathematical model that was calibrated to STAMP trial outcomes, and validated with longer-term outcomes from other published studies, to project clinical and economic outcomes, cost-effectiveness, and budget impact of adding TB-LAM and concentrated urine Xpert to standard sputum Xpert tuberculosis screening in unselected hospitalized patients,” the researchers wrote.

Findings from the STAMP trial — or the Rapid Urine-based Screening for Tuberculosis to Reduce AIDS-related Mortality in Hospitalized Patients in Africa trial — were presented at CROI 2018.

The researchers assessed projected clinical and economic outcomes at 2 years, 5 years and over a lifetime. “Cost-effective” was defined as an incremental cost-effectiveness ratio (ICER) of less than $750/year of life saved (YLS) in Malawi and $940/YLS in South Africa.

With the intervention, life expectancy increased by half a year to 1.2 years, and 51,000 YLSs in Malawi and 171,100 YLSs in South Africa would be saved over 5 years. Moreover, the absolute increase of the TB diagnostic yield was 55% in Malawi and 23% in South Africa. The ICER was $450/YLS in Malawi and $840/YLS in South Africa, demonstrating the cost-effectiveness of the intervention.

“Urine-based tuberculosis testing saves lives and is cost-effective among hospitalized patients with HIV. This should be a public health priority,” Reddy said. “Health care guidelines in areas where HIV and tuberculosis are common should include screening all hospitalized patients with HIV for tuberculosis with urine tests.” – by Marley Ghizzone

Disclosures: The authors report no relevant financial disclosures.

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