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

B Rossetti;S Di Giambenedetto;C Torti;MC Postorino;G Punzi;F Saladini;W Gennari;V Borghi;L Monno;AR Pignataro;E Polilli;M Colafigli;A Poggi;S Tini;M Zazzi;A De Luca;Antiviral Response Cohort Analysis (ARCA) Collaborative Group;A Mandas

Member of the Collaboration Group

2018-01-01

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Abstract

ObjectivesThe aim was to evaluate the evolution of transmitted HIV-1 drug resistance (TDR) prevalence in antiretroviral therapy (ART)-naive patients from 2006 to 2016.MethodsHIV-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.ResultsWe 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/L [interquartile range (IQR) 169-521 cells/L], and the median viral load was 4.7 log(10) HIV-1 RNA copies/mL (IQR 4.1-5.3 log(10) 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 log(10) 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 1year more recent: AOR 0.95; 95% CI 0.91-0.99; P=0.02).ConclusionsThe prevalence of HIV-1 TDR has declined during the last 10years in Italy.