Incidence of tuberculosis among reported AIDS cases in Quebec from 1979 to1996

Background: The impact of HIV infection on tuberculosis (TB) rates in Quebe c has not been fully established. Because concurrent HIV infection is the s ingle most important factor in TB reactivation, the authors used Quebec AID S surveillance data to quantify the extent of TB among reported AIDS cases and to identify the characteristics of AIDS patients with TB. Methods: The study population comprised people aged 15 years and over with AIDS diagnosed between lan. 1, 1979, and Dec. 31, 1996, and reported by Mar . 31, 1997. Patients with TB (all Forms) and those without TB were compared . Multivariate logistic regression analysis was used to examine the indepen dent effect of each variable on the AIDS-TB cases. The authors also compare d the number of AIDS-TB cases with the number of TB cases to estimate the e ffect of HIV infection on TB incidence. Results: Of the 4684 people with AIDS reported in Quebec, 242 (5.2%) had ac tive TB at some point during the course of their illness. During 1992-1995, 9.6% of the people with TB in Montreal, and 5.8% in the province of Quebec , also had HIV infection. Those with AIDS and TB were predominantly male (7 5.2%), manual workers (40.1%) and residents of Montreal (86.4%) and were bo rn in an HIV-endemic country (63.8%). The multivariate analysis indicated t hat AIDS patients who were born in HIV-endemic countries in the Caribbean, sub-Saharan Africa or other developing regions were 21.8 times (95% confide nce interval [CI] 19.5-28.5), 17.9 times (95% CI 12.7-27.1) and 4.9 times ( 95% CI 3.5-7.0) more likely to have TB than those born in Canada; manual wo rkers and unemployed people with AIDS were 1.6 times (95% CI 1.3-2.0) and 2 .0 times (95% CI 1.5-2.6) more likely to have TB than professional workers; and people who acquired HIV infection through heterosexual contact were 2. 1 times (95% CI 1.6-3.1) more likely to have TB than men who acquired it th rough sexual contact with other men. Interpretation: AIDS seems to contribute significantly to the number of TB cases. The results of this study reinforce the importance of offering HIV t esting to people in high-risk groups, such as those born in a country where HIV and TB is endemic.