Thesis (Master's)--University of Washington, 2012Objectives: The primary aims of this study were to estimate the proportion of SnPTB in HIV co-infected patients, to identify the clinical, demographic, and radiographic factors associated with SnPTB, and to compare TB treatment outcomes and survival rates between patients diagnosed with SnPTB and SpPTB. Methods: A retrospective cohort of TB/HIV co-infected patients who started TB treatment between 2005 and 2010 under the TB control Program at posts, health centers, hospitals, or at one of five reference hospitals providing care for HIV-infected patients under the Ministry of Health system in three regions of the Peruvian Amazon. Results: Of the 332 patients with TB and HIV co-infection, 220 patients were included in this study. 56.8% patients were diagnosed with SnPTB and in the multivariate model, three factors were associated with a diagnosis of SnPTB: concurrent opportunistic infection (OR=4.8, 95%CI: 1.4-16.4), and alveolar infiltrate (OR=7.9, 95%CI: 1.9-31.8) or miliary infiltrate (OR=29.3, 95%CI: 4.3-199.7) on chest radiography. Forty-five percent of patients had an unsuccessful. Treatment at a level II or III health facility (OR=4.8, 95%CI: 2.1-10.8), and a history of addictive habits (OR=5.7, 95%CI: 1.8-18.2) were associated with increased likelihood of unsuccessful TB treatment outcome. Compared to SpPTB, SnPTB was associated with an 85% increased risk of death at one year (HR=1.85, 95%CI: 1.1-3.24), after adjusting for CD4 cell count, completed treatment, age, concurrent opportunistic infection, chronic pre-existing conditions, and use of HAART. The majority of deaths (74%) occurred while receiving TB treatment. Among patients with SnPTB, the median delay between diagnosis and initiation of TB treatment was two days (IQR=0-5). In the multivariate analysis, treatment delay was higher among patients with a history of addictive habits (OR=3.6, 95%CI: 1.1-12.1) and in patients living farther from the health facility. Conclusions: More aggressive TB surveillance and treatment monitoring activities should be routinely performed in smear negative patients. Further studies are needed to develop and evaluate innovative and inexpensive methods to ensure that patients living distant from health facilities or affected by alcohol abuse receive appropriate monitoring and therapy. Key words: smear negative pulmonary tuberculosis, treatment outcome, HIV infection