Demographic, laboratory and clinical characteristics of HIV-positive tuberculosis cases in Canada

Abstract

Summary: Background: Human immunodeficiency virus (HIV) is an important risk factor for the global incidence and mortality of tuberculosis (TB) and has had a tremendous impact on the epidemiology and the control of the disease. The purpose of this study was to determine the demographic, laboratory and clinical characteristics of HIV-positive TB cases in Canada as compared to HIV-negative cases. Methods: TB cases reported to the Canadian TB Reporting System (CTBRS) from 1997 to 2006 were retrospectively reviewed and for those with known HIV serostatus, the distributions of age, sex, country of birth, smear and culture positivity, drug resistance, site of disease and treatment outcome were compared. Results: 2710 TB cases had a report of an HIV test with a 12.9% positivity rate. HIV-positive cases were more likely to be 30–44 years old, male, Canadian born non-Aboriginal or African born. Sputum and lymph node biopsies were significantly more likely to be smear-positive and sputum was more likely to be culture positive. Anti-TB drug resistant rates were similar, except for lower streptomycin resistance in new HIV-positive cases. HIV-positive cases were significantly more likely to present with miliary or central nervous system TB, to have multi-system disease, to have lower treatment success rates (66.4% versus 88.5%) and to have a 5.6 higher case-fatality rate. Interpretation: HIV-positive cases have a different demographic profile, present with more advanced and severe forms of disease, have poorer treatment outcomes and higher mortality. All TB cases should be tested for HIV so as to offer appropriate case management and treatment. Keywords: Tuberculosis, HIV, Demography, Risk factors