title: A multi-state model to estimate incidence of heroin use.
abstract: BACKGROUND
  Existing incidence estimates of heroin use are usually based on one information source. This study aims to incorporate more sources to estimate heroin use incidence trends in Spain between 1971 and 2005.
  
  
  METHODS
  A multi-state model was constructed, whereby the initial state "heroin consumer" is followed by transition to either "admitted to first treatment" or to "left heroin use" (i.e. permanent cessation or death). Heroin use incidence and probabilities of entering first treatment ever were estimated following a back-calculation approach.
  
  
  RESULTS
  The highest heroin use incidence rates in Spain, around 1.5 per 1,000 inhabitants aged 10-44, occurred between 1985 and 1990; subdividing by route of administration reveals higher incidences of injection between 1980 and 1985 (a mean of 0.62 per 1.000) and a peak for non-injectors in 1990 (0.867 per 1,000).
  
  
  CONCLUSIONS
  A simple conceptual model for heroin users' trajectories related to treatment admission, provided a broader view of the historical trend of heroin use incidence in Spain.
authors: Drug Abuse Epidemiology Research Group, IMIM-Institut de Recerca Hospital del Mar, Doctor Aiguader 88, Barcelona, Spain.
authors: Albert
authors: A
authors: Sánchez-Niubò
authors: Odd O
authors: OO
authors: Aalen
authors: Antònia
authors: A
authors: Domingo-Salvany
authors: Ellen J
authors: EJ
authors: Amundsen
authors: Josep
authors: J
authors: Fortiana
authors: Kjetil
authors: K
authors: Røysland
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D003932:Heroin / Q000506:poisoning; D006556:Heroin Dependence / Q000453:epidemiology* / Q000534:rehabilitation; D006801:Humans; D015994:Incidence; D016013:Likelihood Functions; D008875:Middle Aged; D016012:Poisson Distribution; D011159:Population Surveillance / Q000379:methods*; D013030:Spain / Q000453:epidemiology; D015819:Substance Abuse, Intravenous / Q000453:epidemiology; D055815:Young Adult
chemical_list: D003932:Heroin