Background: The Department of Health and Human Services (DHHS) HIV guidelines outline recommendations on when to obtain genotypic HIV resistance in antiretroviral therapy (ART) experienced individuals. We conducted a single center study to examine utilization/ordering patterns of HIV genotypes, detection of acquired resistance, and impact of genotypic ordering on change in an ART regimen. Further we sought to determine whether the results obtained from genotype testing per DHHS guidelines influenced treatment decisions more than those obtained off-guidelines.
Methods: All HIV genotypes ordered between 5/2011 5/2012 and 3/2015 3/2016 in a large urban health system caring for 2000 HIV-infected individuals were assessed. Baseline pre-treatment genotypes were excluded from analyses. Chart review was performed for testing rationale, provider perceived medication adherence, resistance mutations detected, and ART changes.
Results: 146 genotypes were reviewed. The most common rationales for ordering are in figure 1. Only 96 genotypes had HIV-RNA > 1000 cps/ml and were resulted. The most common off-guidelines reason for which a genotype was ordered was due to a patient being off ART more than 4 weeks: 44 (30%) of all genotypes ordered. Sixty genotypes were ordered per DHHS guidelines (virologic failure while on ART) and these samples had a similar rate of detectable viremia compared to off-guidelines tests (72% vs 62%, p=0.2) but were significantly more likely to have new resistance mutations detected (22% vs. 7%, p=0.009) and lead to a change in ART (22% vs 2%, p<0.001)(see figure 2). ART was not frequently modified as a result of new mutations detected in genotypes ordered off-guidelines because the new mutation(s) did not affect the current/last ART regimen.
Conclusion: Despite DHHS recommendations on appropriate timing for HIV genotypic resistance testing, our quality improvement investigation found many areas where ordering practices can be optimized. Our findings suggest that there is little utility in sending genotypic analysis for a reason other than a detectable VL with either good or poor adherence. These findings are consistent with DHHS level A recommendations and provide additional objective measures to support these guidelines.
J. Castillo-Mancilla, None
E. M. Gardner, None