Stable frequency of HIV-1 transmitted drug resistance in patients at the time of primary infection over 1996-2006 in France.

BACKGROUND: Transmission of drug-resistant variants is influenced by several factors, including the HIV-1 RNA levels in HIV-1-infected patients. Our study describes the transmitted drug-resistant virus among 1446 French patients diagnosed at the time of primary infection and included from 1996 to 2006 along with the proportion of chronically infected treated patients in the French Hospital Database on HIV (FHDH).
METHODS: Genotypic resistance tests were performed at the time of primary infection. The proportion of patients with viral load <500 copies/ml among treated patients, enrolled in the FHDH, was calculated.
RESULTS: Over 1996-2006, the proportion of transmitted resistant viruses to at least one antiretroviral was estimated as 10.9%. When considering class resistance, there was an increase in transmission of nonnucleoside reverse transcriptase inhibitor-resistant virus from 0.6% in 1996-1998 to 4.4% in 1999 (P = 0.034), whereas no change was evidenced for either nucleoside/nucleotide reverse transcriptase inhibitor or protease inhibitor resistance. In the FHDH, the proportion of patients receiving combination antiretroviral therapy (cart) increased from 27.7% in 1996 to 81.4% in 2006 and the proportion of viral load <500 copies/ml in treated patients increased from 17.0% in 1996 to 85.3% in 2006. Phylogenetic analysis revealed that 25.5% of patients harboured HIV-1-non-B virus at the time of primary infection in 2005-2006 compared to 10% in 1996-1998.
CONCLUSION: In this large study of patients at the time of primary infection, the frequency of acquired resistant virus was stable over time, over 5% for nucleoside/nucleotide reverse transcriptase inhibitor and nonnucleoside reverse transcriptase inhibitor. One explanation for this stability may be the increasing number of treated patients in virological success.