Urine-based TB testing identifies additional cases
BOSTON — The addition of systematic urine screening to sputum screening identified more cases of tuberculosis and was associated with a 50% increase in treatment among hospitalized patients with HIV in sub-Saharan Africa, according to findings from the STAMP trial.
“HIV/TB coinfection causes around one in four admissions to hospitals in sub-Saharan Africa,” Ankur Gupta-Wright, BSc, MBBS, MRCP, MSc, DTM&H, clinical research fellow at the London School of Hygiene & Tropical Medicine, said during a press conference. “It is a common cause of death and we know that up to half of fatal TB remains undiagnosed, so our current sputum-based TB testing approach is failing this patient population.”
For the STAMP trial, Gupta-Wright and colleagues screened all patients with HIV irrespective of TB symptoms who were admitted to the hospital between October 2015 and September 2017. Their final analysis included 2,574 patients who were treated at two facilities in South Africa and Malawi. The patients were randomly assigned to TB screening with a sputum-based assay or both urine-based and sputum-based assays. The urine-based assays used in the study were the TB LAM lateral flow assay (Alere), which is a urine dipstick test, and the widely available Xpert MTB/RIF assay (Cepheid), Gupta-Wright said.
Baseline characteristics were similar between the study arms. Overall, 38.7% had suspected TB and 72.3% were on ART upon admission. The median CD4 cell count was 227 cells/L.
Patients tested with urine-based assays were significantly more likely to be diagnosed with TB than patients screened with a sputum-based test alone (21.9% vs. 14.9%; P < .001). Gupta-Wright said the addition of urine-based testing was associated with a 50% increase in TB treatment. In addition, there were fewer deaths among patients screened with urine-based assays; however, this reduction was limited to sicker patients, such as those with CD4 cell counts of less than 100 cells/L or severe anemia, according to Gupta-Wright. Among these patients, there were up to 23% fewer deaths.
“So, for every 100 HIV-positive patients admitted to a hospital who would be screened for TB using the new urine-based testing in addition to sputum testing, we could diagnose approximately seven extra TB cases and save approximately three lives,” Gupta-Wright said. “The findings of our trial support the use of urine-based TB screening, and we hope it will change how we screen for TB in HIV-positive admissions to a hospital in places with a high burden of HIV and TB.” – by Stephanie Viguers
Gupta-Wright A, et al. Abstract 38LB. Presented at: Conference on Retroviruses and Opportunistic Infections; March 4-7, 2018; Boston.
Disclosure: Gupta-Wright reports no relevant financial disclosures.