267019 Mean HIV viral load among resident cases and the undiagnosed in Oregon

Wednesday, October 31, 2012 : 10:45 AM - 11:00 AM

Jeff Capizzi, BA , HIV/STD/TB Program, Oregon Public Health Division, Portland, OR
Sean Schafer, MD , HIV/STD/TB Program, Oregon Public Health Division, Portland, OR
Lea Bush, BA , HIV/STD/TB Program, Oregon Public Health Division, Portland, OR
Background: Community viral load estimates do not account for undiagnosed HIV, which comprises 20% of the infected population. We estimated mean viral load (MVL) (the population viral load) for all living HIV-infected Oregon residents aged ≥13 years, including those undiagnosed.

Methods: We determined the number of resident cases from address at last lab report; we estimated undiagnosed cases as 20.1% of living cases. We selected the last viral load during the prior 1.5 years for resident cases and, for the undiagnosed, used the mean of first viral load results following diagnosis (2006-2011). We calculated z-scores to compare group differences in geometric mean.

Results: We estimated that 6,986 people with HIV lived in Oregon during August 2011, including 5,582 resident cases and 1,404 undiagnosed. MVL among resident cases and those undiagnosed was 6,884 copies/mL. MVL among resident cases was 92 copies/mL, 80% of whom had viral loads ≤200 copies/mL. We estimated the 1,404 undiagnosed had a MVL of 33,884 copies/mL. Resident cases with higher MVLs were more likely to be African American than white (p<0.001), less likely to have AIDS (p<0.001), and more likely to be injection drug users (IDU) vs. men who have had sex with men (MSM) (MSM/IDU p=0.001; IDU p=0.037). MVL was highest among 20-24 year-olds, decreasing with age. Higher MVLs among the undiagnosed were found among males (p=0.001), those with AIDS (p<0.001), and male IDU vs. MSM (p=0.001).

Conclusion: Including estimates for the undiagnosed increased Oregon's MVL 74-fold and provides a more realistic index of community-wide risk.

Learning Areas:

Learning Objectives:
Explain how to estimate the prevalence of HIV infection based on HIV surveillance data Describe groups with the highest mean viral load among diagnosed and among undiagnosed cases

Keywords: HIV/AIDS, Surveillance

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am an HIV epidemiologist in the Oregon HIV/STD/TB Program. I have over 15 years experience, working in HIV surveillance and research in HIV care utilization and medication adherence. Among my scientific interests has been the development of methods to estimate the prevalence of HIV infection, care utilization, and disease severity.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.