[The HIV epidemiology in province of Modena: use of two different sources of data]. / L'utilizzo di due fonti di dati diverse nella descrizione dell'epidemia da HIV nella Provincia di Modena.

OBJECTIVE: to analyse demographic characteristics and risk factors of people living with HIV and to compare data from the surveillance system for new HIV diagnoses with those from the National AIDS Registry (RAIDS). DESIGN: comparison of two surveillance systems. SETTING: province of Modena. PARTICIPANTS: cases reported to the RAIDS and to the HIV surveillance system, from 1985 to 2004 regarding residents in the province of Modena. MAIN OUTCOMES: number of cases and incidence, by exposure categories, age, and gender. RESULTS: from 1985 to 2004, 615AIDS cases and 1731 new HIV diagnoses were reported among residence in the province of Modena. The incidence of AIDS progressively decreased after 1995, whereas incidence of new HIV diagnoses remained stable since 1994 with annual rates up to three-fold higher than those reported for the AIDS cases. Individuals with a new HIV diagnosis were younger (<30 years of age), with a higher proportion of females and heterosexuals compared to AIDS cases. The most represented age group among AIDS cases was 30-49 years whereas it was <30 years for newly diagnosed HIV cases. The proportion of intravenous drug users decreased over time both among new AIDS cases and new HIV diagnoses, whereas the proportion of cases attributed to sexual transmission increased. The proportion of foreigners among newly diagnosed HIV cases was twice as high as among AIDS cases. CONCLUSIONS: this study shows that, especially after the introduction of highly active antiretroviral therapies, information on AIDS cases has become less representative of the trends to HIV epidemic. Therefore, AIDS surveillance systems should be combined with local surveillance systems on new HIV diagnoses.