VEdeTTE, a longitudinal study on effectiveness of treatments for heroin addiction in Italy: study protocol and characteristics of study population.

The aim of this study was to provide a methodological overview of the study design of the national evaluation large-scale study VEdeTTE and a description of the VEdeTTE study population and to compare enrollments with refusals and the study population with the overall clients at the National Health System (NHS) treatment centers. VEdeTTE is a longitudinal study of heroin addicts recruited in 115 NHS treatment centers in Italy, 1998-2001; 11,903 people were enrolled, 3876 refused to participate; data were analysed on 10,454. Information from refusals was compared to enrollments. The characteristics of the cohort were compared to those of all patients treated in 1999 in Italy. Refusals had a lower educational level and less regular occupational status than those enrolled. Fourteen percent of enrolled patients were women; heroin users in the VEdeTTE study were older than patients attending all NHS treatment centers in Italy; incident cases were less represented. The majority of participants had more than 8 years of education, 33.5% were regularly employed, and only 2% did not have a fixed address. Injectors were 72.3%; 40.6% had a previous overdose, and 14.3% had been imprisoned for life; 15.7% shared injection equipment during the previous 6 months. The proportion of participants reporting heroin use approximately halved from the beginning of the current treatment to the time of the interview. The VEdeTTE study is the biggest cohort of heroin addicts attending treatment centers in Europe. The Italian heroin-addicted population under treatment seems to have low level of education but good social integration. Compared with men, women show a higher severity. Participants show a beneficial effect of treatment.