Reduced injection frequency and increased entry and retention in drug treatment associated with needle-exchange participation in Seattle drug injectors

The association between needle exchange, change in drug use frequency and e nrollment and retention in methadone drug treatment was studied in a cohort of Seattle injection drug users (IDUs). Participants included IDUs classif ied according to whether they had used a needle exchange by study enrollmen t and during the 12-month follow-up period. The relative risk (RR) and the adjusted RR (ARR) were estimated as measures of the association. It was fou nd that IDUs who had formerly been exchange users were more likely than nev er-exchangers to report a substantial (greater than or equal to 75%) reduct ion in injection (ARR = 2.85, 95% confidence limit [CL] 1.47-5.51), to stop injecting altogether (ARR = 3.5, 95% CL 2.1-5.9), and to remain in drug tr eatment. New users of the exchange were five times more likely to enter dru g treatment than never-exchangers. We conclude that reduced drug use and in creased drug treatment enrollment associated with needle exchange participa tion may have many public health benefits, including prevention of blood-bo rne viral transmission. (C) 2000 Elsevier Science Inc. All rights reserved.