APH 2001, 59, 63-75:

Estimate of the prevalence of injecting drug use in Belgium.

F. Sartor, D. Walckiers, A. Sasse and L. Bils

Keywords: epidemiology, prevalence, injecting drug use, HIV, treatment demand, Belgium

Objective: To estimate the number of injecting drug users (IDUs) aged 15-54 years in Belgium in 1995.

Method: The number of IDUs has been inferred from the number of alive HIV persons, the prevalence rate of IDU among HIV patients, and the prevalence rate of HIV seropositivity among IDUs.  Data were provided by the national HIV/AIDS register and by the database on treatment demands recorded by the monitoring system of the French Community.  The 95% confidence limits (95% CL) of the estimate were constructed using the bias-corrected and accelareted bootstrap method.

Results: In 1995, the number of IDUs, 15-54 years old, was estimated to be 20,000 (95% CL: 10,.00 - 46,300) yielding to a prevalence rate of 0.36% (95% CL: 0.18-0.83%).

Discussion: The Belgian HIV/AIDS register exhaustively records confirmed HIV seropositive and AIDS cases.  The prevalence of IDU among HIV patients can therefore be directly estimated from this database.  A sample of drug users demanding a treatment in the French Community provided an estimate of the prevalence of self-reported HIV seropositivity in the population of IDUs living in Belgium.  This estimate could be used at a national level since the results obtained later in a survey conducted in Flanders were quite comparable to those found in the French Community.  In addition, self-reported HIV seropositivity was found to be a good indicator of HIV status based on saliva and blood testing.  Confidence limits of the estimated prevalence of IDU were mainly dependent on the reliability of the estimated prevalence of HIV seropositivity among IDUs.