Reviewed by Susa Coffey, MD

Summary

Weinstock et al examined the prevalence of antiretroviral (ARV) resistance in 1,082 persons newly diagnosed with HIV infection in 10 U.S. cities between 1997 and 2001. Detuned enzyme immunoassay testing indicated that 21% of study subjects had been infected during the previous 6 months, while the remainder had HIV infection of unknown duration. These subjects were naive to ARV therapy (ART) and presumably were infected with drug-resistant strains of HIV virus. Mutations associated with reduced susceptibility to ARVs were found in 8.3% of the overall group. The prevalence of ARV resistance was highest in men who have sex with men (MSM) (12%), in whites (13%), and in patients with a partner who was taking ART (15%); it was lowest in Hispanic and African American heterosexual men and African American women (4.3-4.9% for each group). Resistance mutations were found more frequently in subjects recently infected with HIV than in the rest of the cohort; this difference was not statistically significant. The prevalence of ART mutations varied by drug class (nucleoside reverse transcriptase inhibitor mutations were most common) and increased in the later study years among chronically infected subjects.

Commentary

This study reveals a high prevalence of ARV mutations in newly diagnosed HIV-infected individuals in 10 cities. The fact that most subjects were not recently infected reinforces other data showing that transmitted ARV resistance mutations may remain detectable beyond the period of acute infection. (1) The prevalence and the persistence of ARV mutations suggest an important role for resistance testing in newly diagnosed HIV-seropositive patients, regardless of their date of infection. It also highlights the pressing need for more effective counseling of patients to prevent the transmission of HIV, whether drug resistant or wild type.

References

1.	Little S, Koelsch K, Ignacio C, et al. Persistence of Transmitted Drug-resistant Virus among Subjects with Primary HIV Infection Deferring Antiretroviral Therapy. 11th Conference on Retroviruses and Opportunistic Infections; February 8-11, 2004; San Francisco. Abstract 36LB.

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