Detection of drug resistance mutations at low plasma HIV-1 RNA load in a European multicentre cohort study.

Methods: A total of 16 511 HIV-1 reverse transcriptase and protease sequences from 11 492 treatment-experienced patients were identified, and linked to clinical data on viral load, CD4 T cell counts and antiretroviral treatment history. Test results from 3162 treatment-naive patients served as controls. Multivariable analysis was employed to identify predictors of reverse transcriptase and protease DRMs.

Results: Overall, 2500/16 511 (15.14%) test results were obtained at a viral load 1000 copies/mL. Individuals with viral load levels of 1000-10000 copies/mL showed the highest probability of drug resistance to any drug class. Independently from other measurable confounders, treatment-experienced patients showed a trend for DRMs and other mutations to decrease at viral load levels 500 copies/mL.

Conclusion: Overall, 2500/16 511 (15.14%) test results were obtained at a viral load 1000 copies/mL. Individuals with viral load levels of 1000-10000 copies/mL showed the highest probability of drug resistance to any drug class. Independently from other measurable confounders, treatment-experienced patients showed a trend for DRMs and other mutations to decrease at viral load levels 500 copies/mL.