European Network to Develop Policy Relevant Models and Socio-Economic Analyses of Drug Use, Consequences and Interventions Final report: Part 5 – Pilot project to develop a model of geographic spread of drug misuse in the European Union

The groups work began by considering a computerised model of geographic spread, developed based on the observation that macro spread of drug use may behave similar to infectious diseases (using ‘infection rates’ between cities and towns). At the XV international scientific meeting of the international epidemiological association, Florence, 1999 a paper (by Frischer and Heatlie) was presented which estimated and mapped the most likely spread of peak incidence of problem drug use in the West of Scotland. A key issue considered by the group was geographic data representation, e.g. crude rates, rate ratio's or rather the statistical significance of these. Maps were developed showing the increase over time of people entering drugs treatment in the different Italian provinces, suggesting that spread of problem drug use followed international trade routes. New developments include an improved (more user friendly and integrated) version of the GIS drug forecasting program, a discussion on the use of socio-economic indicators for prevalence estimates, presentation of the work and available data of Eurostat, a method to incorporate geographical links between regions into mapping, and a case study of a Lisbon neighbourhood. The Drug Incidence & Prevalence Estimation Program (DIPEP) has been updated from a DOS to windows environment.

One of the aims of drug prevention and treatment programmes is to help people to stop using drugs and slow down initiation of new drug use. However these aims are rarely operationalised into specific targets and it is difficult to subsequently gauge their impact at a population level. DIPEP was used to illustrate the potential effect of drug polices. In the first example a harm reduction programme which reduced the average career of a drug user from 10 years to 5 years, for an epidemic starting in 1990 would reduce the prevalence of drug use in England in the year 2000 from an estimated 251,000 to 112,000. In the second example, a prevention program which reduced the proportion of the population using drugs from 0.6% to 0.3%, for an epidemic starting in 1995 would reduce prevalence from 172,000 to 85,000 in 2005. These predictions depend on the validity of the model's conception of how drug misuse spreads among the general population. Obviously more complex scenarios can be envisaged and we hope to augment the programme to accommodate different forms of drug use that may diffuse in different ways. This work was presented at the national methadone conference. Melbourne, November 2000.

European Data
In Europe there is greater availability of other epidemiological data such as hospital treatment data and public health data, potentially through focal points. However our investigations to date indicate that the coverage of this data is very uneven. Further harmonisation of this data is required across Europe before it can be meaningfully mapped.

Contributions from the network.
Two successful meeting were held in Lisbon and Jersey. Several participants presented their work on geographical aspects of drug use, which demonstrate significant advances in this area.

Demonstration of the integrated GIS drug forecasting program (Ken Field)

Using socio-economic indicators for prevalence estimates (Petra Kuemmler)

Presentation of Eurostat data and GIS work (Torbiorn Carlquist)

Exploration and modelling of drug misuse in Italy: a space-time approach”

(Giovanna Lasinio)

Thoughts for future drug misuse mapping..." (Mathew Hickman)

Mapping the Incidence of Problem Drug Use in a Neighbourhood – The

hardcore population of drug users in “Casal Ventoso” (Lisbon)” (Alberto Teixeira)

At the first meeting in Lisbon in December 1998, theoretical issues were foremost. At this meeting, it became clear that innovative practical work has been done in at least three centres (UK, Italy and Portugal).

Update local prevalence maps
New local prevalence estimates were sent to Keele and integrated into a new European map, This appeared in the 1999 EMCDDA annual report. Maps produced at Keele also feature in the 2000 report.

Objectives and Achievements
The groups objective was to develop models for estimating and forecasting geographical spread of problem drug use in the EU. Our final TSER report reviews the targets set in each six month period and how these were met.