Favourable evolution of virological and immunological profiles in treated and untreated patients in Italy in the period 1998-2008.

Background: This study provides an estimate of the proportion of HIV-positive patients in Italian clinics showing an 'adverse prognosis' (defined as a CD4 count ≤200cells/μL or an HIV RNA >50 HIV-1 RNA copies/mL) over time, and investigates whether this proportion varied according to patients' characteristics. Methods: We estimated the annual proportion of patients with a CD4 count ≤200cells/μL or HIV RNA >50copies/mL out of the total number of patients in the Icona Foundation cohort seen in any given year, both overall and after stratifying by demographical and treatment status groups. Generalized estimating equation models for Poisson regression were applied. Results: In 1998-2008, the prevalence of patients with a CD4 count ≤200cells/μL decreased from 14 to 6% [adjusted relative risk (RR) 0.86/year; 95% confidence interval (CI) 0.84-0.88; P<0.0001]. The prevalence of HIV RNA >50copies/mL decreased from 66 to 40% (adjusted RR 0.95/year; 95% CI 0.95-0.96; P<0.0001) in all patients and from 38 to 12% in the subgroup of patients who had previously received antiretroviral therapy (ART) for ≥6 months (adjusted RR 0.89/year; 95% CI 0.88-0.90; P<0.0001). Conclusions: There was a substantial increase in the success rate of ART in Italy in 1998-2008, resulting in a lower percentage of patients with adverse prognosis in recent years. The use of ART seemed to be the most important determinant of viral load outcome, regardless of mode of transmission. Although injecting drug users showed a less marked improvement in CD4 cell count over time than other risk groups, they showed a similar improvement in detectable viral load.