Efficacy of mobile telephone contact for follow-up in injecting heroin users.
Background: Prospective follow-up of heroin users is known to be difficult due to their unstable lifestyle, and high follow-up rates have usually demanded major tracking efforts. In Sweden, mobile telephones are commonly used by heavy drug users for drug trading. Objectives: This methodology study aims to examine the efficacy of mobile telephone contact for prospective follow-up interviews with in
