BOSTON (FRONTLINE MEDICAL NEWS) – Urine-based screening for tuberculosis added to standard sputum-based screening can reduce the risk of TB-associated deaths among hospitalized patients with advanced HIV compared with sputum-based screening alone, results of a randomized trial indicate.

Among 2,574 hospitalized HIV-positive patients, the rate of death at 56 days, the primary endpoint, was 21.1% for patients screened with standard-of-care sputum testing using the Xpert MTB/RIF assay, compared with 18.3% for patients screened with sputum testing and urine-sample testing by the Xpert MTB/RIF and the Determine TB-LAM urine dipstick test, reported Ankur Gupta-Wright, MBBS, MRCP , from the London School of Hygiene and Tropical Medicine.

However, the reductions in mortality seen with the urine-based screening were observed only in the patients with more advanced HIV infections (CD4 cell counts below 100/uL), he said at the annual Conference on Retroviruses and Opportunistic Infections (CROI).

“For every 100 patients who are HIV-positive admitted to hospital, with screening for TB using new urine-based testing in addition to sputum testing we can diagnose approximately seven extra TB case, and save approximately three lives,” he said at a briefing following his presentation of the data in a late-breaking oral abstract session.

“The findings our trial support the use of urine-based TB screening, and we hope to change how we screen for TB in HIV-positive admissions in the hospital in places with high burden of HIV and TB,” he said, speaking on behalf of colleagues in the STAMP Study.

HIV-related TB caused an estimated 400,000 deaths worldwide in 2016, and is responsible for between 32% and 67% of deaths in HIV-positive adults admit to hospitals in Africa. Yet half of all of those cases of TB are undiagnosed at the time of death, he said.

Urine based screens are easily obtained and have good diagnostic yield for disseminated TB, which is common in patients with advanced HIV, he said.

To see whether adding urine screening could increase TB diagnosis and treatment and reduce TB deaths among hospitalized HIV+ patients, the investigators enrolled 2,600 unselected HIV+ adults admitted to hospitals in South Africa and Malawi. Patients less than 18 years of age, those who had been treated for TB with the last 12 months or had received TB prophylaxis with isoniazid within the last 6 months were excluded, leaving a sample size of 2,574.

The patients were randomly assigned to standard-of-care Xpert MTB/RIF sputum screening either alone or with the addition of the two urine-based screens already described.

The overall absolute difference in risk of death at 56 days was -2.8% favoring urine screening (P = .074). As noted, this difference was only significant among patients with CD4 counts below 100/uL. Among these patients, mortality rates for nonurine screened versus screened were 35.7% vs. 28.8%, respectively (P = .036).

Baseline hemoglobin below 8 g/dl and TB suspected at admission were also predictive of better outcomes with the addition of urine-based screening.

An analysis of time to death stratified by baseline CD4 cell count also showed the advantage of urine screening for the sickest patients, with an adjusted hazard ratio for patients with CD4 counts below 100 of 0.77 (P = .047).

The urine-based screening also lead to significantly more microbiologically confirmed and clinically diagnosed TB, and more TB treatment (P less than .001 for each).

A separate cost analysis, presented in a scientific poster ( CROI 2018 Abstract 1117LB ), showed that the incremental cost-effectiveness ratios for the urine-based intervention were $490 per year of life save in Malawi, and $850 per year of life saved in South Africa.

The study was funded by UK AID, the UK Medical Research Council, and the Wellcome Trust. Dr. Gupta-Wright reported having no conflicts of interest to disclose.

SOURCE: Gupta-Wright, A et al. CROI 2018, Abstract 38LB.