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AIDS 2012 Recap: Testing and Linkage to Care in San Francisco

, by Reilly O'Neal

“Testing and linkage to care” emphasizes raising HIV status awareness and expanding antiretroviral treatment and medical care to those newly diagnosed (and ready and willing to take daily antiretroviral pills). San Francisco advocates, researchers, and clinicians helped pioneer this approach, and in early 2010, the San Francisco Department of Public Health (SFDPH) and San Francisco General Hospital formalized their policy of offering antiretroviral treatment to all HIV-positive people regardless of CD4 cell count—a measure of immune system health and disease progression long used to guide the timing of treatment initiation. (United States guidelines, updated in March 2012, now recommend treatment for all HIV-positive people.)

The benefits of early HIV treatment and care are two-fold. First, starting treatment earlier with today’s more tolerable and potent drugs helps preserve immune function, leading to better individual health, and second, early treatment has been shown to reduce the likelihood of HIV transmission to uninfected sex partners. In the much-lauded HPTN 052 study, for example, early treatment not only kept treated partners healthier but also helped reduce HIV transmission by a remarkable 96%.

At AIDS 2012, researchers reported on San Francisco’s testing and linkage to care approach and its effects on viral suppression (reflected in reduced viral load, the amount of HIV’s genetic material found in a sample of blood), and raised further questions about expanding treatment for all.

Trends in Treatment Initiation

First off, are people starting treatment early in San Francisco? Ling Hsu of SFDPH and colleagues answered this question in a poster discussion on trends in the length of time between HIV diagnosis and treatment initiation between 2004 and 2010. Among the 3,858 people involved in the analysis, the median (most commonly reported) time from diagnosis to treatment initiation fell considerably, from 27 months in 2004 to 5 months in 2010. The proportion of people who started treatment within just three months of their HIV diagnosis rose from 25% to 43% between 2004 and 2010.

Of course, this begs the question of why the remaining 57% of newly diagnosed people in this analysis did not start treatment early in 2010. The research team cautioned that not everyone is benefiting equally from the city’s test-and-treat strategy; for example, African-Americans, people who inject drugs, young people (under age 30), and residents of low-income neighborhoods started treatment later, they reported.

The Effect of Test-and-Treat on Viral Suppression

Second, do people who start treatment early in San Francisco see bigger declines in viral load? In another poster discussion with a smaller sample, Hsu and colleagues reported data from 1,285 people diagnosed with HIV in San Francisco between 2008 and 2010. Most (83%) in this study entered medical care within three months of their diagnosis.

Viral suppression, defined in the study as viral load below 200 copies/mL, was linked with time to entry into care. Among those who accessed medical care early (within three months after their HIV diagnosis), 55% had viral suppression within one year, compared with 46% who started care four to twelve months after their diagnosis and only 17% of people who entered care more than a year after learning their HIV status or who did not enter care. “Delayed or poor engagement in HIV care impacts viral suppression,” the researchers concluded, with implications for both individual health and HIV transmission.

In another analysis, Elvin Geng of the University of California at San Francisco and colleagues examined trends in viral load from 2001 to 2011. Among nearly 6,000 people starting HIV care at the San Francisco General Hospital HIV/AIDS Clinic, the proportion of those who maintained viral suppression (here defined as viral load below 500 copies/mL) for one year rose dramatically during this time period, from 36.2% in 2001 to 72.3% in 2011.

The researchers also detected trends in viral suppression according to the individuals’ CD4 count at entry into care: “Mean clinic viral loads declined for all [patient] groups, but changes plateaued for those with the lowest CD4 levels while they accelerated for those with the highest CD4 counts.” These trends, the researchers concluded, demonstrate the effects of both more potent antiretroviral therapy and the city’s recent expansion of antiretroviral treatment to people with higher CD4 counts.

Comparison with Other Major U.S. Cities

How does San Francisco’s experience stack up against that of other urban areas with significant HIV epidemics? At AIDS 2012, Nanette Benbow of the Chicago Department of Public Health and colleagues presented an interesting comparison of proportions of people in HIV care, on treatment, and virally suppressed in Chicago, Los Angeles County, Philadelphia, and San Francisco in 2009.

For the purposes of this analysis, the researchers defined “linked to care” as having had at least one CD4 or viral load test within three months of HIV diagnosis; “engaged in care” was defined as having had at least one of these tests in the 2009 study period.

The proportion of people linked to care, engaged in care, and on treatment was significantly higher in Los Angeles and San Francisco compared with Chicago and Philadelphia, the team reported, with San Francisco in the lead: 50% of newly diagnosed people in San Francisco and 47% in Los Angeles were on antiretroviral therapy, compared with 34% in Philadelphia and 26% in Chicago (and against 36% in the U.S. overall).

Viral suppression followed a similar trend, with 46% of those in San Francisco and 41% in Los Angeles having a viral load below 200 copies/mL at their last test, compared with 27% in Philadelphia and 22% in Chicago.

This study also found health disparties: “Across all cities a higher percentage of Whites compared to Blacks who accessed care were on [antiretroviral therapy] and were virally suppressed,” the researchers noted. “Data from these cities highlight discrepancies in progress towards universal HIV care, and help identify effective regional interventions that promote access to care and treatment.”

Putting It All Together

Taken together, these reports suggest that San Francisco’s efforts to increase HIV status awareness and engage people in care and treatment are paying off in terms of viral suppression, a primary measure of HIV disease progression and the body’s response to antiretroviral therapy.

Higher rates of viral suppression translate to reduced “community viral load,” a snapshot of the amount of virus present in a given population and an indicator of HIV health, which is also linked with rates of new HIV infections; for example, an analysis by Moupali Das of SFDPH and colleagues found that community viral load in San Francisco fell between 2004 and 2008, alongside a significant decrease in new HIV diagnoses (from 798 in 2004 to 434 in 2008).

Increased engagement in life-saving medical care and reductions in community viral load are good news for San Francisco. However, these studies also raise questions about what prevents people from accessing medical care and HIV treatment, and why not everyone who does start treatment early experiences viral suppression. As Benbow and colleagues concluded, “Targeted programs and funding are needed to ensure care and eliminate racial/ethnic disparities.”

Reilly O’Neal is the editor of BETA.

Selected Sources

Benbow, N. and others. Linkage, retention, ART use and viral suppression in four large cities in the United States. 19th International AIDS Conference (19th IAC). Washington, D.C. July 22–27, 2012. Abstract MOPDC0303.

Das, M. and others. Decreases in community viral load are accompanied by reductions in new HIV infections in San Francisco. PLoS ONE 5(6): e11068. 2010.

Geng, E. and others. Trends in clinic viral load at a public health HIV/AIDS clinic in San Francisco from 2001–2011. 19th IAC. Abstract TUPE035.

Hsu, L. and others. Using HIV/AIDS surveillance data to evaluate if a HIV test-and-treat strategy leads to viral suppression. 19th IAC. Abstract WEPE111.

Hsu, L. and others. Trends in antiretroviral treatment initiation among persons diagnosed with HIV in San Francisco, 2004–2010. 19th IAC. Abstract WEPE135.

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