In-hospital costs (for both in-patient and day-care admissions) were based on the DRG system in use in Italy since 1994, in which disease groups Roscovitine concentration are defined according to the hospital discharge form data. Costs

of out-patient consultations and examinations (laboratory and clinical imaging) were calculated based on the official standard costs assigned by the Italian Ministry of Health. According to an agreement between the Italian Ministry of Health and all pharmaceutical companies, hospitals pay half price for antiretroviral drugs, instead of the full cost paid by the public in Italy. All costs in this analysis were annualized and expressed in nominal terms for the year in which they were incurred. Costs incurred by patients (e.g. costs of travel to hospital services or costs of additional services incurred by staying at home), intangible costs (e.g. stress and anxiety) and indirect costs to society (e.g. loss of productivity) were Metabolism inhibitor not estimated, as they did not affect the comparison of medical sector burden between chronic diseases, which was the main objective of the study. For the

same reasons, the cost analysis did not take into consideration the inflation rate, which the Italian National Institute of Statistics confirmed to be 2.1% on average at the time of our study. The criteria for the identification of HIV-infected persons were as follows: a diagnosis of HIV infection based on serological testing; For an HIV-infected person to be considered as having a concomitant chronic disease, they had to satisfy at least one of the above criteria for that chronic disease. HIV-infected persons who were at any time on antiretroviral treatment during the year were classified as ‘on antiretroviral treatment’. A verification procedure to assess the sensitivity of the BLHA database for detecting HIV-infected patients was performed through cross-checking of patients registered in the databases to of the following institutions operating

in the Province: the Institute of Infectious and Tropical Diseases, the Clinic for Sexually Transmitted Diseases, Methadone Dispensing Units, and Primary Health Care Services for HIV Patients. Death certificates were also reviewed. Cross-checking verified that the BLHA database missed only 4% of patients registered in the other available databases. Starting from 2004, all newly identified cases were considered as ‘incident’ cases, by which we mean ‘newly diagnosed’ rather than ‘newly infected’. To calculate a denominator for the annual prevalence and incidence, we used an estimate of the mid-year average number of people who received services from the Brescia Local Health Authority during a calendar year.