Genotype testing at HIV diagnosis may not provide clinical benefit for most patients and may not be cost-effective compared with current treatment, according to a study published in Clinical Infectious Diseases.

The United States (US) Department of Health and Human Services and International AIDS Society USA guidelines recommend standard genotype resistance testing for people newly diagnosed with HIV. Standard genotype testing at HIV diagnosis (baseline genotype) has 2 functions: to guide selection of initial antiretroviral therapy (ART) to optimize viral suppression from the outset and to establish a baseline resistance profile that can help select subsequent ART regimens, if changes are needed because of drug toxicity during viral suppression therapy. For example, standard genotype results evaluate resistance to nucleoside reverse transcriptase inhibitor (NRTI), nonnucleoside reverse transcriptase inhibitor (NNRTI), and protease inhibitor (PI) drug classes, which inform any necessary changes in ART regimens.

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For the majority of people with HIV in the US, the current treatment guidelines recommend an integrase strand inhibitor paired with an NRTI as first-line ART. Therefore, baseline genotype results currently guide the choice of initial NRTI pair, given transmitted NRTI resistance (NRTI-R). With this evolution of HIV treatment, the role and value of baseline genotype testing has become uncertain. This study determined the clinical and economic value of baseline genotype testing for people newly diagnosed with HIV in the US.

To examine clinical effect and cost-efficacy for people starting ART with dolutegravir and an NRTI pair, researchers used the Cost-effectiveness of Preventing AIDS Complications (CEPAC) model. This is a validated model that simulates HIV disease, clinical care, and costs of treatment throughout an individual’s lifetime while tracking health outcome. The simulated characteristics of adults included a mean age of 35 years, 81% male, and a mean initial CD4 count of 346/µL. In total, 4 subgroups of adults newly diagnosed with HIV and starting ART were modeled: those with no transmitted drug resistance (83.8% of total), those with transmitted NRTI-R (5.8%), those with transmitted NNRTI resistance (NNRTI-R; 7.2%), and those with transmitted PI resistance (3.2%). Each standard genotype test cost $320, HIV RNA tests cost $110, and routine HIV care costs ranged from $300 to $1200 a month.

Results showed that baseline genotype testing did not provide clinical benefit for most patients and was not cost-effective. When compared with no baseline genotype testing, baseline genotype testing would add <1 additional undiscounted quality-adjusted life-day and cost $500 more per person. Using the univariate sensitivity analysis, the clinical benefits of baseline genotype testing did not exceed 5 quality-adjusted life-days for all people newly diagnosed with HIV. However, baseline genotype testing did show benefit in those with transmitted drug resistance, which comprised only 6.8% of all the people newly diagnosed with HIV, including 5.8% with NRTI-R and 1% with transmitted NNRTI-R who experienced dolutegravir adverse events. However, this benefit was significantly lower than that of other HIV interventions, including improved engagement in care, expanded HIV testing, and preexposure prophylaxis.

Overall, the study authors concluded that, “Given currently recommended HIV treatment regimens in the US, a resistance genotype at HIV diagnosis is not cost-effective; inclusion of this test in baseline evaluation of adults newly diagnosed with HIV should be reconsidered.”

Reference

Hyle EP, Scott JA, Sax PE, et al. Clinical impact and cost-effectiveness of genotype testing at HIV diagnosis in the United States [published online May 4, 2019]. Clin Infect Dis. doi:10.1093/cid/ciz372