Trend of mortality observed in a cohort of drug addicts of the metropolitan area of Bologna, North-Eastern Italy, during a 25-year-period

The aim of our study is to evaluate the temporal trend of deaths in a cohort of i.v. drug users (IVDU) followed in a city of Northen Italy (Bologna), and to assess its relationship with HIV infection and AIDS, and availability of potent anti-retroviral therapy. One thousand and 214 IVDUs (mainly heroin addicts), 916 males and 298 females, attending an out-patient service for treatment and prevention of substance abuse between 1977 and November 1996, were enrolled into our observational cohort, and their vital status was ascertained up to December 31, 2002. The large majority of enrolled subjects were born in the Bologna metropolitan area and surroundings; no extra-European immigrants were present. During the observation period, 271 IVDUs (22.3%) died, 211 males (23.0%), and 60 females (20.1%). No death was recorded before 1984. Main death causes result as follows: AIDS (52.8% of episodes), heroin overdose (22.1%), street accidents (7.4%), decompensated liver cirrhosis (6.3%), and suicide (2.9%). The highest absolute number of deaths was observed between years 1991 and 1996. Crude mortality rate caused by AIDS was 10.0 per 1000 for males and 13.2/1000 for females; the rate of death due to other causes proved 11.1/1000 among males and 5.2/1000 among females. In most recent years, a sharp decrease in the number of AIDS-related deaths, attributable to the increased use of potent antiretroviral regimens, was recorded among IVDUs, although overall mortality rate remained appreciable.