"During the period 2004-2008, the then National Board of Health supported the DEADHEP project, under which, as part of the study on HIV and hepatitis prevalence among drug-related deaths in Denmark, also by means of autopsies, it was examined whether or not the deceased suffered from hepatitis as a sign of intravenous drug abuse (Christensen et al 2006) (read more in chapter 6). Based on the this, the Danish Health and Medicines Authority started to estimate the number of intravenous drug abusers by comparing DEADHEP with the Danish Health and Medicines Authority’s register on drug users enrolled in treatment (SIB = Stofmisbrugere Indskrevet i Behandling) (Christensen et al 2009). "The estimate is based on a capture-recapture estimate made on newly admitted patients in the treatment registry in each of the years 2003 and 2005 and those registered in DEADHEP in 2006 (a total of 5,126 subjects). The estimate was stratified by age, gender and geographic region and calculated by means of a log-linear model.
"Based on these calculations, the estimate is that at present there are 13,000 active intravenous drug users in Denmark (safety interval of 10,066-16,821). Half of them live east of the Great Belt. Between half and 2/3 are unknown to the treatment system.
"As shown previously in this chapter, the Danish Health and Medicines Authority's overall estimate of the number of drug abusers is 33,000, of which 11,000 are cannabis abusers. As it is estimated that there are 13,000 intravenous drug abusers in Denmark, it is assumed that around 60% of the drug abusers (not including cannabis abusers) are intravenous drug users (primarily users of opioids).
"The 13,000 intravenous drug users equal 3.6/1000 inhabitants between 15 and 64 years in Denmark (95%, safety interval of 2.8-4.6). The proportion of intravenous drug users in the Danish population equals the share of drug abusers in the other European countries of 1-5/1000 of the 15-64-year-olds (EMCDDA 2010).
"Number of intravenous drug users calculated by mortality
"As a supplement to the above calculations, an estimate was made on the number of intravenous drug users in Denmark from a multiplicative model based on the mortality observed among intravenous drug users in treatment during the period 2004-2006. The mortality observed among intravenous drug users in treatment was 2.0/100 person years and the calculated number of deaths were an average of 225/year. This equals a one-year prevalence of 11,186 (95%, safety interval of 9,670-15,634). The estimate is slightly lower than the 13,000 observed when using the capture-recapture method."


Sundhedsstyrelsen (National Board of Health), "2012 National Report (2011 data) to the EMCDDA by the Reitox National Focal Point: Denmark: New Development, Trends and in-depth information on selected issues," (Copenhagen, Denmark: Sundhedsstyrelsen, Nov. 2012), pp. 31-32.