HIV Testing among Canadian Tuberculosis Cases from 1997 to 1998

Recent evidence suggests a global rise in adult tuberculosis (TB) cases associated with HIV/AIDS. The World Health Organization, the United States Centers for Disease Control and Prevention, and the Public Health Agency of Canada advocate universal screening of all TB cases for HIV. The contribution of HIV to the TB burden in Canada remains unclear.

A retrospective cohort study was conducted of all TB cases reported in Canada from 1997 to 1998. The aim was to determine the proportion of patients that had an HIV test on record, and of these, the number of patients infected with HIV.

From 1997 to 1998, 3767 TB cases were reported to the national TB surveillance system. In the present study, 3416 case records (90.7%) were included. The number of cases with a record of an HIV test was 736 (21.5%), and of these, 41.2% were tested within one month of TB diagnosis. Among the 703 cases with known HIV test results, the prevalence of HIV infection was 14.7%. Cases with an HIV test on record were more likely to have one or more risk factors for HIV, and also were more likely to be male, aged 15 to 49 years, of Aboriginal ethnicity, and to have smear-positive TB and both pulmonary and extrapulmonary disease at the time of diagnosis.

These results suggest that HIV testing of TB patients is not universal, but rather selective, and is likely based on perceived risk factors for HIV as opposed to TB diagnosis alone.