AIDS 2012: HIV Viral Load Trends in San Francisco, 2001-2011

More potent antiretroviral regimens and a policy of offering treatment to everyone who tests HIV positive regardless of CD4 T-cell count has led to widespread viral suppression and a declining "community viral load" in San Francisco, researchers reported at the XIX International AIDS Conference (AIDS 2012) last month in Washington, DC.

A growing body of evidence suggests that earlier antiretroviral therapy (ART) may be beneficial well before the development of advanced immune deficiency indicated by a low CD4 count. Recent studies have also shown that treatment is effective as prevention.

In early 2010, San Francisco General Hospital and the San Francisco Department of Public Health instituted a new policy of giving all newly diagnosed individuals the opportunity to start ART immediately, rather than waiting until their CD4 cell count fell to 350 or 500 cells/mm³. In March 2012, U.S. Department of Health and Human Services treatment guidelines followed suit.

In many U.S. cities, getting people with HIV tested and into care before they develop serious immune deficiency is a more pressing concern, but San Francisco has comparatively good HIV services and people enter care with a higher CD4 count and better overall health, on average, than in many other urban areas. Local community viral load is relatively low, but the average is brought down by a larger proportion of older, higher-income gay men who have a history of stable, state-of-the-art care.

Elvin Geng, Diane Havlir, and colleagues from the University of California at San Francisco conducted a study to look at how evolving treatment standards have translated into routine care for a "safety-net" public health clinic population in which a large proportion of patients have psychiatric comorbidities and psychosocial or socioeconomic factors associated with poorer health outcomes.

The researchers evaluated 2245 untreated adults -- defined as 90 days or more without ART -- who entered care at San Francisco General Hospital's HIV/AIDS clinic between January 1, 2001, and December 30, 2011.

Most patients (87%) were men, the median age was about 40 years, about half were white, and about 20% had a history of injection drug use. One-third entered care with a CD4 count < 200 cells/mm³, 24% had 201-350 cells/mm³, 20% had 351-500 cells/mm³, and 24% had > 500 cells/mm³.

The investigators assessed trends in clinic-wide viral load and proportions of patients who maintained viral load suppression -- using a relatively high threshold of < 500 copies/mL, because tests early in the decade had a higher limit of detection -- both overall and stratified by CD4 cell level when they entered care.

Results

• The proportion of patients with consistently suppressed viral load rose steadily over the entire study period, while the proportion with HIV RNA > 50,000 copies/mL fell.
• About 15% of patients had suppressed HIV RNA in 2001, rising to about 25% in 2003, 30% in 2005, nearly 40% in 2007, about 50% in 2009, and just over 60% in 2011.
• Trends differed, however, based on CD4 count at entry into care, with people who entered with lower CD4 cell levels achieving viral suppression sooner.
• For people who entered care with < 200 cells/mm³, the average HIV RNA level rose from approximately 43,000 copies/mL in 2001 to 115,000 copies/mL in 2003, falling back down to 8000 copies/mL in 2005 and < 500 copies/mL from 2007 on.
• For those who entered care with 201-350 cells/mm³, viral load fell steadily from approximately 21,000 copies/mL in 2001 to 10,000 copies/mL in 2003 to 4000 copies/mL in 2005 to 400 copies/mL in 2007, then to < 500 copies/mL for the remaining years.
• For those who entered care with 351-500 cells/mm³, viral load was approximately 14,000 copies/mL in 2001 and 15,000 copies/mL in 2003 (with a dip to 10,000 copies/mL in between), then down again to 11,000 copies/mL in 2005, 7000 copies/mL in 2007, 2000 copies/mL in 2009, and thereafter < 500 copies/mL.
• Finally, for people who entered care with > 500 cells/mm³, viral load fell from 10,000 copies/mL in 2001 to 7000 copies/mL in 2003, up to 9000 copies/mL in 2005 and 2007, then down to 5000 copies/mL in 2009, only reaching < 500 in 2011.

"The fraction of patients who are consistently suppressed increased dramatically over the course of the last decade," the UCSF researchers concluded. "[I]ncreasingly potent drugs and expanding treatment indications have changed the suppression of HIV RNA from the exception to the rule," even in an urban clinic setting where psychiatric comorbidities and substance use are common.

"The rise in suppression among patients with lower CD4 levels occurred earlier in the decade, likely as a result of the expanding selection of potent antiretroviral medications," they continued. "Increasing HIV RNA suppression among patients with higher CD4 levels later in the decade may reflect expanding treatment indications."

At a San Francisco preview of UCSF research prior to the DC conference, Geng noted that currently 50% to 60% of patients achieve viral suppressed after 1 year on ART. People who start treatment at higher CD4 levels do not have worse virological outcomes over time, he added, suggesting that concerns about problems maintaining long-term treatment are not borne out.

8/17/12

Reference

E Geng, CB Hare, K Christopoulos, D Havlir, et al.Trends in clinic viral load at a public health HIV/AIDS clinic in San Francisco from 2001-2011. XIX International AIDS Conference (AIDS 2012).  Washington, DC, July 22-27, 2012. Abstract TUPE035.