Resistance patterns analyzed in regional study of HIV patterns

Genotype test is routine for ART-naïve patients

A Midwestern clinic showed a high prevalence of primary antiretroviral resistance among HIV patients from 2003 to 2005, suggesting that it's worth the cost to obtain genotypes on new patients, a study suggests.1

"I think one of the reasons we thought the study was relevant is because we do have a fair mix of heterosexual transmission and men who have sex with men (MSM) and females in our clinic," says Jessica R. Grubb, MD, an instructor of medicine at Washington University in St. Louis, MO.

"The different geographical locations may have different patterns of resistance, and ours are limited to what we have at a university clinic," Grubb notes. "But it may also reflect other parts of the country that don't have high immigration rates."

In the last few years, most of the university clinic's treatment-naïve HIV patients receive genotypes, which follows the recent trend among HIV clinicians, Grubb says.

"Unless there's some drastic reason, we'll wait for the genotype," Grubb says. "So at our clinic, usually we'll obtain a genotype at the patient's first visit, and then when we see the patient again we'll make a decision for their care based on the guidelines of standard therapy and the genotype profile."

The genotype adds to the whole picture, giving clinicians an idea of which regimens to avoid, she adds.

Investigators conducted a retrospective analysis of all genotypes performed on the treatment-naïve patients seen between 2003 and 2005, and they found that 7 percent of the subjects had a K103 mutation, Grubb says.

"If a patient has a K103 mutation, you would not want to start him on a Sustiva-based regimen," Grubb notes. "So many people are started on Sustiva these days, it's good to know if they're going to be resistant against it."

TAM or nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations were found in 5 percent of patients, she adds.

"That's more difficult to characterize because you'd have to make that determination on an individual basis," Grubb says. "But it would be helpful to know what the mutation is, and then you could have a more goal-directed decision on antiretrovirals."

Patients who have antiretroviral resistance before they start therapy should be given reinforcement counseling about medication adherence, Grubb suggests.

"They already may have a reduced response to some medications, and they have limited their options already, even before they started their treatment," she says.

At the university clinic, these patients meet with a clinician for an hour of HIV education, Grubb says.

"A nurse practitioner sits down with them and reviews all educational questions and compliance issues," she says. "And we have case managers and social workers who assist."


  1. Grubb J, Singhatiraj E, Mondy K, et al. Patterns of primary antiretroviral resistance in antiretroviral-naive HIV-1 infected individuals. Presented at the Infectious Diseases Society of America 44th Annual Conference, held Oct. 12-15, 2006, in Toronto, Ontario. Abstract: 977.