Mycobacterium tuberculosis infection and disease are not associated with protection against subsequent disseminated M. avium complex disease.

OBJECTIVE

To determine the relationship between Mycobacterium tuberculosis infection and disease and subsequent disseminated M. avium complex (MAC) disease in HIV-infected persons.

DESIGN

A prospective observational cohort study.

SETTING

The AIDS Linked to the Intravenous Experience (ALIVE) cohort of injecting drug users and the Johns Hopkins Hospital Adult HIV Clinic (JHHAHC).

PARTICIPANTS

HIV-infected persons aged > 18 years with CD4 lymphocytes < 100 x 10(6)/l were followed between July 1989 and 31 October 1996. There were 182 persons in the ALIVE cohort and 1129 persons in JHHAHC who met these criteria.

MAIN OUTCOME MEASURE: The relative risk of disseminated MAC was determined according to a history of prior opportunistic infection, MAC prophylaxis, antiretroviral therapy, M. tuberculosis infection or disease, race, sex, and injecting drug use.

RESULTS

Amongst the 30 patients with active tuberculosis, eight developed disseminated MAC, compared with 208 cases of disseminated MAC amongst 1148 patients without prior M. tuberculosis infection or disease [relative risk (RR), 1.5; 95% confidence interval (CI), 0.8-2.7; P=0.2]. Amongst the 10 patients with extrapulmonary tuberculosis, five developed disseminated MAC (RR, 2.8; 95% CI, 1.5-5.2; P=0.02). Injecting drug use was associated with a decreased risk of disseminated MAC (RR, 0.7; 95% CI, 0.6-0.9; P=0.007). In a logistic regression analysis, disseminated MAC was significantly associated with extrapulmonary tuberculosis and other opportunistic disease, whereas antibiotic prophylaxis and injecting drug use were protective.

CONCLUSIONS

A history of M. tuberculosis infection or disease was not associated with protection against subsequent disseminated MAC disease in HIV-infected persons. However, persons with extrapulmonary tuberculosis were at increased risk for disseminated MAC, particularly at low CD4 cell levels.