[ALEE-AO: epidemiologic and economic atlas of hospital activities in Lombardy].

This paper describes the main characteristics of a data processing system that is available through the Internet and that is used to process epidemiological and economic data, predominantly from a geographical viewpoint, starting from the hospital discharge abstracts of the Lombardy Region. Technical aspects of the system are briefly reviewed, including epidemiological-statistical aspects (incidence, prevalence, variety of diagnoses, indicators, controlling for statistical variability, etc.) and aspects relating to information systems (hardware platform, software environment, Internet access and security problems, original database, etc). The system introduces several methodological innovations in the processing of hospital discharge abstracts (such as links between data files, evaluation of activity of each individual GP, and analysis of patient mobility), proposes three successive levels of case selection (time, geography, nosology) prior to statistical analysis which is performed starting from the information on each individual discharge abstract. Finally, several examples are given and critical aspects, as well as prospects of the system, are discussed.