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.
This methodology study aims to examine the efficacy of mobile telephone contact for prospective follow-up interviews with injecting heroin users recruited at the syringe exchange program of Malmö, Sweden.
Seventy-eight heroin users with mobile telephone numbers were included. Subjects reported using heroin for 28 days of the previous 30 days, and only 8% reported they had recently been engaged in work or studies. Clients were contacted between 15 and 21 times over 2 years, with each contact attempt generally involving two telephone calls on consecutive days.
During follow-up, 68% of subjects had been successfully contacted for at least one follow-up interview (on average 6.9 interviews), and 25% of follow-up attempts were successful. In 23% of the sample (n=18), at least 50% of follow-up attempts were successful, and these subjects tended to be older (p=.05) and more likely to be female (p=.07), whereas follow-up rates were unrelated to baseline heroin use.
Despite limited effort, and despite the severe situation of intravenous heroin users, mobile telephone contact can be used with heavy drug users in the present setting.