[en] Adult ; Aged ; Aged, 80 and over ; Anti-HIV Agents/pharmacology ; Belgium/epidemiology ; Drug Resistance, Viral/genetics ; Female ; Genotype ; HIV Infections/epidemiology/physiopathology/transmission/virology ; HIV Protease/genetics ; HIV Reverse Transcriptase/genetics ; HIV-1/drug effects/genetics/isolation & purification ; Humans ; Male ; Middle Aged ; Molecular Sequence Data ; Prospective Studies ; Questionnaires ; RNA, Viral/blood/genetics/isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; Sequence Analysis, DNA
[en] This study is the first prospective study to assess the prevalence, epidemiology, and risk factors of HIV-1 drug resistance in newly diagnosed HIV-infected patients in Belgium. In January 2003 it was initiated as part of the pan-European SPREAD program, and continued thereafter for four inclusion rounds until December 2006. Epidemiological, clinical, and behavioral data were collected using a standardized questionnaire and genotypic resistance testing was done on a sample taken within 6 months of diagnosis. Two hundred and eighty-five patients were included. The overall prevalence of transmitted HIV-1 drug resistance in Belgium was 9.5% (27/285, 95% CI: 6.6-13.4). Being infected in Belgium, which largely coincided with harboring a subtype B virus, was found to be significantly associated with transmission of drug resistance. The relatively high rate of baseline resistance might jeopardize the success of first line treatment as more than 1 out of 10 (30/285, 10.5%) viruses did not score as fully susceptible to one of the recommended first-line regimens, i.e., zidovudine, lamivudine, and efavirenz. Our results support the implementation of genotypic resistance testing as a standard of care in all treatment-naive patients in Belgium.