Report on the Drug Situation 2010 - Bundesministerium für ...

approximations and have to be interpreted with caution. The prevalence rate of alcoholdependence, compared to illicit drugs, is estimated to be 5% of the population over 15in Austria. This means that a total of 350 000 people in Austria are to be regarded asalcoholics (Uhl et al. 2009).4.1 Prevalence and incidence estimates of PDUIn Austria scientific estimates of the prevalence of problem drug use are only availablefor opioids and for poly-drug use with opioids. GÖG/ÖBIG has updated the estimateswhich so far have been available up to 2007 (GÖG/ÖBIG 2010b): now the years 2008and 2009 are covered as well (GÖG/ÖBIG, under preparation). For the capture-recapturemethod, on which the prevalence estimate is based, data on opioidsubstitution treatment and reports to the police relating to opioids were used.However, the problem of ghost cases is a significant deficit regarding the quality ofsubstitution data 15 .In order to correct the resulting bias, i.e., the tendency to overestimate prevalencerates, data from the year 2004 were used to derive a correction formula (GÖG/ÖBIG2010b). Figure 4.1 shows the time series of prevalence estimates with and without acorrection for ghost cases. When interpreting these figures one has to bear in mindthat the correction factor calculated for the year 2004, due to correction routines inthe substitution registry (see Chapter 5.4), may assume a number of ghost cases thatis too high, which in turn leads to underestimates of prevalence rates. For this reason,the estimated current prevalence of problem drug use including opioid use in 2009can only be given as a fairly rough approximation: between 25 000 and 37 000 people(prevalence estimate corrected for ghost cases in 2009: 25 777; 95% confidence interval:24 867—26 687; prevalence estimate without correction for ghost cases in 2009:35 252; 95% confidence interval: 33 976—36 529). If these figures are combined withother data sources, it is safe to assume that the prevalence rates of PDU, after a rise in2004, have gone down again and have remained at similar levels in recent years (fordetails see GÖG/ÖBIG 2008c and GÖG/ÖBIG 2010b). For 2007, the results of the twosampleCRC estimates could be verified to a large extent by means of a three-sampleCRC estimate which included drug-related deaths (GÖG/ÖBIG, under preparation).15If the end of treatment is not documented, the corresponding clients appear in the statistics as people currentlyundergoing treatment also in the years after the actual end of treatment (= ghost cases).28 © GÖG/ÖBIG, <strong>Report</strong> on the Drug Situation 2010