Browsing by Author "Walter, Nicholas D."

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    C-Reactive Protein Testing for Active Tuberculosis among Inpatients without HIV in Uganda: a Diagnostic Accuracy Study
    (Journal of Clinical Microbiology, 2020) Meyer, Amanda J.; Ochom, Emmanuel; Turimumahoro, Patricia; Byanyima, Patrick; Sanyu, Ingvar; Lalitha, Rejani; Kaswabuli, Sylvia; Andama, Alfred; Walter, Nicholas D.; Katamba, Achilles; Cattamanchi, Adithya; Worodria, William; Huang, Laurence; Yoon, Christina; Davis, Lucian
    The objective of this prospective cross-sectional study, conducted at a national referral hospital in Kampala, Uganda, was to determine diagnostic performance of serum C-reactive protein (CRP) as a triage test for tuberculosis (TB) among HIV-seronegative inpatients. We calculated the sensitivity, specificity, positive and negative likelihood ratios, and positive and negative predictive values to determine the diagnostic performance of a CRP enzyme-linked immunosorbent assay (ELISA) (Eurolyser) in comparison to that of a reference standard of Mycobacterium tuberculosis culture on two sputum samples. We constructed receiver operating curves and reported performance in reference to the manufacturer’s cutoff and also to a threshold chosen to achieve sensitivity of 90%, in accordance with the WHO’s targetproduct profile for a triage test. Among 119 HIV-seronegative inpatients, 46 (39%) had culture-positive pulmonary TB. In reference to M. tuberculosis culture, CRP had a sensitivity of 78% (95% confidence interval [CI], 64 to 89%) and a specificity of 52% (95% CI, 40 to 64%) at the manufacturer’s threshold of 10 mg/liter. At a threshold of 1.5 mg/liter, the sensitivity was 91% (95% CI, 79 to 98%) but the specificity was only 21% (95% CI, 12 to 32%). Performance did not differ when stratified by illness severity at either threshold. In conclusion, among HIV-seronegative inpatients, CRP testing performed substantially below targets for a TB triage test. Additional studies among HIV-seronegative individuals in clinics and community settings are needed to assess the utility of CRP for TB screening.
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    Effect of anti-retroviral therapy on oxidative stress in hospitalized HIV-infected adults with and without TB
    (African health sciences, 2018) Musisi, Emmanuel; Matovu, Denis K.; Bukenya, Andrew; Kaswabuli, Sylvia; Zawedde, Josephine; Andama, Alfred; Byanyima, Patrick; Sanyu, Ingvar; Sessolo, Abdul; Seremba, Emmanuel; Davis, Lucian J.; Worodria, William; Huang, Laurence; Walter, Nicholas D.; Mayanja-Kizza, Harriet
    HIV infection and opportunistic infections cause oxidative stress (OS), which is associated with tissue damage. Anti-retroviral therapy (ART) is used to treat HIV and decrease the risk of opportunistic infections, but it is unclear whether ART reduces OS. Association of ART with OS was investigated. Methods: We stratified a convenience sample of frozen serum or plasma from HIV-infected, ART-naïve (n= 21); HIV-infected, ART-treated (n= 14); HIV and PTB co-infected, ART-naïve (n= 21); HIV and PTB co-infected, ART-treated (n= 25) patients. Controls (n= 21) were HIV-negative adults without TB symptoms. Concentration of OS markers namely: transaminases (ALT and AST), gamma glutamyl transpeptidase (GGT), albumin, total protein, malondialdehyde (MDA), vitamin C, and total anti-oxidant status (TAS) were determined. Results: AST (p< 0.001), GGT (p< 0.001), total protein (p= 0.001) and MDA (p< 0.001) were higher in HIV patients compared to controls. Vitamin C (P< 0.0001) and albumin (p< 0.01) were lower in HIV-patients relative to controls. ART was only associated with higher albumin (p= 0.001), higher GGT (p= 0.02) and lower vitamin C (p= 0.009). HIV and PTB co-infection was only significantly associated with higher GGT (p= 0.01) and AST (p= 0.03). Conclusion: We identified severe OS among HIV-patients. ART was associated with both increased and reduced markers of OS hence suggesting that ART may not attenuate OS.
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    Test and Treat: A New Standard for Smear-Positive Tuberculosis
    (Journal of acquired immune deficiency syndromes, 2012) Davis, J. Lucian; Dowdy, David W.; Boon, Saskia den; Walter, Nicholas D.; Katamba, Achilles; Cattamanchi, Adithya
    Optimizing sputum smear microscopy, the principal method of tuberculosis (TB) diagnosis in high-burden settings around the world, is a critical priority for global TB control. To improve rates of testing, completion, and reporting, the World Health Organization (WHO) recently endorsed a policy of same-day diagnosis of TB by microscopy. Unfortunately, the implementation of this policy has emphasized same-day sputum collection alone, with patients required to return on a subsequent day to collect results. We use a simple decision analysis to demonstrate that the timing of results reporting has a greater impact on treatment initiation for smear-positive TB cases than the timing of specimen collection. Same-day diagnosis of smear-positive TB, including sputum collection and reporting of smear results, should be the new global standard.