Evolution of transmitted HIV-1 drug resistance and viral subtypes circulation in Italy from 2006 to 2016.

OBJECTIVES: The aim was to evaluate the evolution of transmitted HIV-1 drug resistance (TDR) prevalence in antiretroviral therapy (ART)-naïve patients from 2006 to 2016. METHODS: HIV-1 sequences were retrieved from the Antiviral Response Cohort Analysis (ARCA) database and TDR was defined as detection of at least one mutation from the World Health Organization (WHO) surveillance list. RESULTS: We included protease/reverse transcriptase sequences from 3573 patients; 455 had also integrase sequences. Overall, 68.1% of the patients were Italian, the median CD4 count was 348 cells/µL [interquartile range (IQR) 169-521 cells/µL], and the median viral load was 4.7 log10 HIV-1 RNA copies/mL (IQR 4.1-5.3 log10 copies/mL). TDR was detected in 10.3% of patients: 6% carried mutations to nucleos(t)ide reverse transcriptase inhibitors (NRTIs), 4.4% to nonnucleos(t)ide reverse transcriptase inhibitors (NNRTIs), 2.3% to protease inhibitors (PIs), 0.2% to integrase strand transfer inhibitors (INSTIs) and 2.1% to at least two drug classes. TDR declined from 14.5% in 2006 to 7.3% in 2016 (P = 0.003): TDR to NRTIs from 9.9 to 2.9% (P = 0.003) and TDR to NNRTIs from 5.1 to 3.7% (P = 0.028); PI TDR remained stable. The proportion carrying subtype B virus declined from 76.5 to 50% (P < 0.001). The prevalence of TDR was higher in subtype B vs. non-B (12.6 vs. 4.9%, respectively; P < 0.001) and declined significantly in subtype B (from 17.1 to 8.8%; P = 0.04) but not in non-B subtypes (from 6.1 to 5.8%; P = 0.44). Adjusting for country of origin, predictors of TDR were subtype B [adjusted odds ratio (AOR) for subtype B vs. non-B 2.91; 95% confidence interval (CI) 1.93-4.39; P < 0.001], lower viral load (per log10 higher: AOR 0.86; 95% CI 0.75-0.99; P = 0.03), site in northern Italy (AOR for southern Italy/island vs. northern Italy, 0.61; 95% CI 0.40-0.91; P = 0.01), and earlier calendar year (per 1 year more recent: AOR 0.95; 95% CI 0.91-0.99; P = 0.02). CONCLUSIONS: The prevalence of HIV-1 TDR has declined during the last 10 years in Italy.

Use of efavirenz or atazanavir/ritonavir is associated with better clinical outcomes of HAART compared to other protease inhibitors: routine evidence from the Italian MASTER Cohort.

Randomized trials and observational cohorts reported higher rates of virological suppression after highly active antiretroviral therapy (HAART) including efavirenz (EFV), compared with boosted protease inhibitors (PIs). Correlations with immunological and clinical outcomes are unclear. Patients of the Italian MASTER cohort who started HAART from 2000 to 2010 were selected. Outstanding outcome (composite outcome for success (COS)) was introduced. We evaluated predictors of COS (no AIDS plus CD4+ count >500/mm(3)plus HIV-RNA <500 copies/mL) and of eight single outcomes either at month 6 or at year 3. Multivariable logistic regression was conducted. There were 6259 patients selected. Patients on EFV (43%) were younger, had greater CD4+ count, presented with AIDS less frequently, and more were Italians. At year 3, 90% of patients had HIV RNA <500 copies/mL, but only 41.4% were prescribed EFV, vs. 34.1% prescribed boosted PIs achieved COS (p <0.0001). At multivariable analysis, patients on lopinavir/ritonavir had an odds ratio of 0.70 for COS at year 3 (p <0.0001). Foreign origin and positive hepatitis C virus-Ab were independently associated with worse outcome (OR 0.54, p <0.0001 and OR 0.70, p 0.01, respectively). Patients on boosted PIs developed AIDS more frequently either at month 6 (13.8% vs. 7.6%, p <0.0001) or at year 3 (17.1% vs. 13.8%, p <0.0001). At year 3, deaths of patients starting EFV were 3%, vs. 5% on boosted PIs (p 0.008). In this study, naïve patients on EFV performed better than those on boosted PIs after adjustment for imbalances at baseline. Even when virological control is achieved, COS is relatively rare. Hepatitis C virus-positive patients and those of foreign origin are at risk of not obtaining COS.