Mycobacterium tuberculosis and human immunodeficiency virus co-infection in intravenous drug users on admission to prison.

BACKGROUND

Intravenous drug users (IDUs) and prisoners are groups of great interest in human immunodeficiency virus (HIV) infection and tuberculosis (TB) epidemiology.

AIM

To determine predictors and temporal trends of the co-infection of Mycobacterium tuberculosis and HIV in IDUs on admission to prison.

PATIENTS AND METHODS

Between 1 January 1991 and 31 December 1997, 796 IDUs or former IDUs were studied. Socio-demographic and penitentiary variables were evaluated. HIV-positive patients with > or =5 mm induration on tuberculin test were deemed co-infected. Analysis of factors associated with co-infection was based on a logistic regression model.

RESULTS

Of the incoming prisoners, 44.0% were infected by M. tuberculosis, 43.8% by HIV and 20.1% were co-infected. Co-infection predictors were: 1) total prison time served previously (none, OR 1; <2 years, OR 2.44, 95% CI 1.28-4.64; > or =2 years, OR 4.94, 95% CI 2.56-9.55); 2) age (16-25 years, OR 1; 25-29 years, OR 3.14, 95% CI 1.71-5.75; >29 years, OR 3.67, 95% CI 1.96-6.86); 3) tattoos (OR 1.56, 95% CI 0.98-2.49), 4) syringe sharing (OR 2.43, 95% CI 1.57-3.77) and 5) ex-IDU status (OR 1.87, 95% CI 1.23-2.82). No statistically significant variation in the annual co-infection tendency was observed (OR 1.10, 95% CI 0.98-1.22).

CONCLUSIONS

The high prevalence of co-infection that was detected was associated with risk factors that could be amended by public health intervention.