From 2007 to 2013, the proportion of people who reached an undetectable viral load within 12 months of starting antiretroviral therapy jumped from one-third to three-quarters, according to HIV surveillance data in King County, Washington. Neither race nor HIV transmission group affected time to viral suppression in this study of 1766 people with newly diagnosed HIV infection.
Research demonstrating improved individual health and lowered risk of HIV transmission with immediate antiretroviral therapy led to U.S. and World Health Organization guidelines recommending ART for all HIV-positive people, regardless of CD4+ count. The success of that strategy depends on prompt diagnosis and treatment of HIV infection and continued retention in care and adherence to therapy. The King County study assessed the first link in the continuum of care, time from HIV diagnosis to an undetectable viral load.
The study involved residents older than 14 years diagnosed with HIV infection from 2007 through 2013 in King County, Washington, and reported to the public health service by June 4, 2015. King County includes Seattle and is the 13th most populous county in the United States. The researchers drew data on testing, demographics and transmission characteristics from county surveillance records. They defined viral suppression as HIV RNA ≤200 copies/mL. The analysis excluded people who died as of the time of their deaths and excluded people who migrated from Washington State as of the time of their last laboratory test result.
The analysis included 1766 people, 59% of them 25 to 44 years old. While 89% of the study group were men, 76% were men who have sex with men, 59% white, 17% black and 15% Hispanic. At diagnosis, 45% had a CD4+ count below 350 cells/mm3
, 22% had a count between 350 and 500 cells/mm3
, and 33% had a count above 500 cells/mm3
Of the 1766 people studied, 1490 (84%) reached a viral load below 200 copies/mL in a median of 213 days (95% confidence interval 203 to 229). Among people diagnosed with HIV in 2007, 36% attained viral suppression within 12 months; among people diagnosed in 2013, 77% attained viral suppression within 12 months. In 2007, half of newly diagnosed people attained viral suppression 685 days after diagnosis; in 2013, half of newly diagnosed people attained viral suppression 142 days after diagnosis. Among people with a CD4+ count above 500 cells/mm3 at diagnosis, time to when 50% reached viral suppression fell 87%, from 1112 days in 2007 to 142 days in 2013. Among people with a CD4+ count between 350 and 500 cells/mm3 at diagnosis, time to when 50% reached viral suppression fell 83%, from 717 days in 2007 to 120 days in 2013.
Proportional hazard regression analysis identified four factors independently associated with faster viral suppression: lower CD4+ count, older age, female sex and more recent year of HIV diagnosis. Compared with 2013, hazard ratios for viral suppression were 30% lower in 2012, 29% lower in 2011, 42% lower in 2010, 51% lower in 2009, 57% lower in 2008 and 61% lower in 2007. Neither race/ethnicity nor HIV transmission risk affected time to viral suppression in this analysis.
Overall median time to viral suppression after HIV diagnosis fell 79%, from 685 days in 2007 to 142 days in 2013. The authors believe their findings "highlight the success of one U.S. urban area in instituting early initiation of ART." They note that the study does not explain which factors contributed to this improvement, though possibilities include provider prescribing practices, funding, political climate, patient awareness, and access to medication and the health care system. The researchers argue that U.S. ART guideline changes alone do not explain the rapid improvement in time to viral suppression because they found time to viral suppression among people with the highest CD4+ count fell before 2012, the year U.S. guidelines recommended ART for all.
"In areas like ours," the authors propose, "efforts to minimize the morbidity associated with HIV and diminish transmission should focus on ensuring that HIV diagnoses occur as quickly as possible after infection and promoting the effective treatment for the minority of persons who fail to achieve viral suppression."
Mark Mascolini writes about HIV infection.
Copyright © 2016 Remedy Health Media, LLC. All rights reserved.