Validation in Uganda of the New WHO Diagnostic Algorithm for Smear-Negative Pulmonary Tuberculosis in HIV Prevalent Settings

Background: We compared the effectiveness of the new WHO 2007 diagnostic algorithm for pulmonary tuberculosis (PTB) for HIV prevalent settings (WHO07) to the WHO 2003 guidelines used by the Ugandan National Tuberculosis Program (UgWHO03) and most other countries for the diagnosis of smear-negative PTB. Methods: A prospective observational cohort design was employed under routine operational conditions at a District Hospital in Uganda. Newly diagnosed patients with HIV and enrolled to the outpatient HIV clinic were assessed for possible PTB. The study was in 2 phases with evaluation of the UgWHO03 and WHO07 over the first and second phases, respectively. Results: One hundred forty-seven enrolled onto the UgWHO03 and 166 onto WHO07. There were significant reductions in the geometric mean days (11.0 vs. 21.2, P < 0.05) and number of health facility visits (1.7 vs. 2.8, P < 0.001) from presentation to diagnosis of all PTB for the WHO07 compared with the UgWHO03. For smear-negative PTB, the geometric mean days (28.5 vs. 34.1, P > 0.05) and number of health facility visits (2.5 vs. 2.6, P > 0.05) from presentation to diagnosis were nonsignificantly reduced. Diagnostic sensitivity (95% confidence intervals) for smear-negative PTB increased nonsignificantly from 63% (27% to 90%) to 95% (72% to 100%) for the WHO07, with specificity (95% confidence interval) remaining high at 99% (92% to 100%) and 98% (93% to 100%). Conclusions: Implementing the new WHO07 is likely to reduce the number of days and increase sensitivity for diagnosis of smear-negative cases of PTB. We identified many barriers to implementing both guidelines in HIV prevalent resource-poor settings.