iconafoundation.it). All data are updated at the occurrence

of any clinical event and, in the absence of such an event, at least every 6 months. Immunovirological parameters and serological test results for hepatitis C virus antibody (HCV-Ab) and hepatitis B virus surface antigen (HBsAg) and antibody (HBsAb) are systematically recorded every 6 months; serum creatinine became part of the 6-monthly routine screening after the year 2000. Plasma HIV RNA has been measured using quantitative reverse transcriptase–polymerase chain reaction (RT-PCR; Amplicor, Roche Molecular Enzalutamide System, Pleasanton, CA, USA), a signal ampli®cation branched DNA assay (Quantiplex; Chiron, Emeryville, CA, USA) or nucleic acid sequence-based ampli®cation (NASBA Organon Teknika, Boxtel, the Netherlands). The lower limit of detection of these assays is 500 HIV-1 RNA copies/mL. Ultrasensitive versions (with a lower limit of detection of 50 copies/mL) have been used when appropriate, starting from May 1998. CD4 cell counts are obtained using standard flow cytometry techniques. Creatinine is measured using commercial

assays (upper limit of normal 1.3 mg/dL). Further details regarding the design and data collection are given elsewhere [34]. For this analysis, we included only patients of Italian origin for whom at least two creatinine values, obtained after January 1, 2000 while Metformin cost the patient was still ART-naïve, were available. Included and excluded patients were compared in terms of their demographic and clinical characteristics at enrolment. The eGFR was used to identify patients in the cohort with potential renal dysfunction. The estimate was calculated using the Modification of Diet in Renal Diseases (MDRD) formula [35]: Because ethnicity is not collected in the database, Rutecarpine only patients who were born in Italy were included in the current study and the ethnicity adjustment

of the MDRD formula was omitted under the assumption that nobody was of black ethnicity. Although the MDRD equation has not been independently validated in populations of HIV-infected patients, we have chosen this method and not others because the MDRD estimation of eGFR has been widely used in routine clinical practice and has been specifically recommended by the Infectious Diseases Society of America Guidelines for the assessment of renal function in HIV-infected patients [36]. Baseline was defined as the date of the first of the two consecutive creatinine values after January 2000, while the patient was still ART-naïve. Patients were defined as having an abnormal eGFR value at baseline if both of these two consecutive values were <90 mL/min per 1.73 m2. The prevalence of patients with an abnormal eGFR value at baseline was calculated and the characteristics of these patients were compared with those of patients with normal eGFR (≥90 mL/min per 1.73 m2) using the χ2 test and the Wilcoxon test for independent samples.