Resistance to antiretroviral therapy, even in patients who have never received treatment, is a growing concern. However, genotype resistance testing, which involves looking for the presence of resistance genes, is not a standard procedure at the time a patient is diagnosed with HIV, probably due to lack of data on its benefits and its relatively high cost compared with other routine blood tests.
A cost-effectiveness analysis conducted by a group of Boston researchers indicates that performing genotype resistance testing at initial HIV diagnosis--before treatment is started--can effectively guide a physician's choice of treatment regimen and increase a patient's quality-adjusted life expectancy. (Quality-adjusted measurements of time reflect that survival with an illness is presumed to be of lower quality than healthy survival.)
"For the approximately 90 percent of patients with no resistance, the testing provides no benefit," said lead author Paul Sax, MD, of Brigham and Women's Hospital. "However, if certain types of resistance are present [when a patient is first diagnosed with HIV], our study projects a substantial increase in survival" of more than 14 months, compared with no resistance testing.
Resistance rates vary from place to place. It is estimated that, in the United States and Europe, the average resistance rate in treatment-naive patients is between 8 and 10 percent, although baseline resistance may be as high as 16 percent in gay men, "likely reflecting their overall greater access to treatment since the beginning of the epidemic," said Dr. Sax. Using a model with a resistance rate of just over 8 percent, the analysis estimated a cost of $23,900 per quality-adjusted life year gain
Source:Infectious Diseases Society of America