"From an infectious disease perspective, there is a significant difference between a PDU and an IDU with regard to risk-taking and disease outcome. In 2013, the National Board of Health and Welfare used a new method to estimate the number of IDUs in Sweden. The method uses patient registries and applies a condition based on ICD-10 codes which distinguishes between those who receive a diagnosis of abuse and those who receive any diagnosis related to injecting drug use. The method estimates the number of IDUs at about 8,000 for the whole of Sweden in 2011. 57 per cent of these live in any of the three metropolitan cities: Stockholm, Gothenburg, and Malmö (National Board of Health and Welfare, 2013 (Unpublished)).
"The above estimate also includes the hidden population, i.e. IDUs who maintain a functioning life style and who does not seek help for drug use or any health consequence directly linked to drug use. The estimate is further believed to contribute to prevention efforts being tailored according to needs. The method is to be seen as an attempt to methodologically approach an alternative way with regards to previous PDU estimates, where information was self-reported by a non-randomised number of key information providers, from a non-randomised selection of Swedish regions."
Swedish National Institute of Public Health. "2013 National Report (2012 data) to the EMCDDA by the Reitox National Focal Point: Sweden: New Developments, Trends and in-depth information on selected issues." Östersund: Swedish National Institute of Public Health, 2013, p. 53.