Introduction: this study shows the mortality rates in a retrospective cohort of intravenous drug users attending the public treatment centres (SERT), in the metropolitan area of Bologna, from 1978 to 2004 (3753 subjects, 2926 men and 827 women). The overall mortality rate decreases after 1996 because of the substantial drop of mortality rate owing to AIDS. The overdose mortality increases until 1998 and then decreases; as from 1997 it becomes the first cause of death. The risk of death due to overdose is higher in men than in women, it is higher in subjects treated at SERT during the period 1996-2000 and decreases in subjects treated for more than two years.
Results: the study confirms an over mortality, due to all causes, of the cohort compared with the general population, in accordance with the results of other studies, and a remarkably high mortality for women (SMR in men: 1464; 95% CI 13.45-15.93; SMR in women: 25.61; 95% CI21.53-30.45) as well. Major causes of death among men are, besides overdose and AIDS, cirrhosis, cardiovascular disorders, suicide, lung tumour, and road accidents; among women are suicide, cirrhosis and cardiovascular disorders. The risk of death is higher before 1996 with regard to subjects attending SERT before 1990, and to those who are in treatment for less than two years. Also at higher risk are those subjects with a low schooling level and unemployed.