Health care trajectories and medication consumption of substance users in treatment: linking TDI and IMA databases (Belgium)

Background As problem substance use has a relative low prevalence and is often socially stigmatised, it is rather difficult to study health care trajectories and medication consumption among substance users. In Belgium, the Treatment Demand Indicator register (TDI) is a major information source for drug epidemiology. However, it should be considered as an incidence register as only new drug-related treatment episodes are registered. Linkage with national compulsory health insurance data (IMA) will create a data source in which longitudinal and case-control studies can be performed.