20th International AIDS Conference - Melbourne, Australia


WEPE045 - Poster Exhibition

HIV viral load monitoring frequency and risk of treatment failure among immunologically stable HIV-infected patients prescribed ART

B. Young1,2, R. Debes3, K. Buchacz4, M. Scott2, F. Palella5, J. Brooks4, HIV Outpatient Study (HOPS) Investigators

1International Association of Providers of AIDS Care, Washington DC, United States, 2APEX Family Medicine, Denver, United States, 3Cerner Corporation, Vienna, United States, 4Centers for Disease Control and Prevention, Division of HIV/AIDS Prevention, Atlanta, United States, 5Northwestern University, Chicago, United States

Background: U.S. government guidelines recommend plasma HIV RNA viral load (VL) testing every six months for patients who, while prescribed effective antiretroviral therapy (cART), remain virologically suppressed for at least two years. To assess whether VL monitoring frequency was associated with differential outcomes, we examined rates of subsequent virologic failure (VF) among immunologically stable and virologically suppressed patients prescribed cART, comparing patients who underwent VL testing up to two times per year with those with more frequent VL testing.
Methods: Using data from the HIV Outpatient Study (HOPS), we included patients enrolled from 1993 to 2013 who were not participating in clinical trials, had been prescribed cART for at least two years and maintained VL < 50 copies/mL during that time period, the end of which marked the start of observation (index date, ID) for VF. We required CD4 cell count (CD4) closest to ID during the prior six months to be ≥350 (≥50) cells/mm3. Eligible patients underwent at least one VL test both one year before and after the ID. We defined “less frequent” VL testing as one or two tests/year and “more frequent” testing as greater than two tests/year. VF was defined as any VL ≥200 c/mL within the first year after ID.
Results: Among 1,625 participants, at ID the median (interquartile range [IQR]) age was 48 years (42, 66), 83% were male, median CD4 was 661 cells/mm3 (511, 864). The 1,013 (62%) participants with frequent VL testing and 612 (38%) participants with less frequent VL testing did not differ by age, race/ethnicity, CD4 nadir, or duration of ART. VF was observed among 128 participants: 46 (8%) of less frequent testers and 82 (8%) of more frequent testers (p=0.67). In multivariate modeling, neither VL testing frequency, HIV transmission risk factor, class of ART, or year of ART initiation were associated with VF.
Conclusions: In this large cohort of prospectively followed, immunologically stable and virologically suppressed HIV-infected persons receiving cART, less frequent VL testing was not associated with higher frequency of virologic failure compared with more frequent testing, findings which support current U.S. recommendations for less frequent VL monitoring among effectively treated patients.

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