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  ID Week
Oct 8-12 2014
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HIV Care Cascade Differs by Gender and Age in Large US Healthcare System
  IDWeek 2014, October 8-12, 2014, Philadelphia
Mark Mascolini
Men had significantly greater linkage to HIV care, antiretroviral therapy (ART) prescription, and viral suppression than women in 2010 and 2011 in the Kaiser Permanente healthcare system, despite equal access to care [1]. But those differences disappeared in 2012. People 55 or older had greater retention in care, ART prescription, and viral suppression--but not linkage to care--in all study years.
Descriptions of the HIV cascade of care typically include linkage to care after HIV diagnosis, retention in care over time, prescription of ART, and attainment of viral suppression. The proportion of HIV-positive people declines at each stage [2]. CDC data from 2009 show that 82% of HIV-positive US residents get diagnosed, 66% are linked to care, 37% are retained in care, 33% are prescribed ART, and 25% attain viral suppression [2]. This work and research by Kaiser investigators show gender- and age-based differences in rates of attaining each step.
To update cascade-of-care data and determine whether rates change over time by gender and age, Kaiser investigators conducted a new analysis of their health system members in 2010, 2011, and 2012. Kaiser Permanente is an integrated healthcare system in nine states and the District of Columbia with over 9 million members, including more than 22,000 HIV-positive people in 2013. Everyone in the system has equal access to care.
The cascade analysis involved all Kaiser members at least 13 years old with at least 8 months of membership in a study year. The Kaiser team defined (1) linkage to care as a visit or CD4 count within 90 days of HIV diagnosis for newly diagnosed people or within 90 days of enrolling in Kaiser, (2) retention in care as at least two medical visits at least 60 days apart, (3) filled ART prescriptions as filled prescriptions for a standard regimen for at least 3 months, and (4) viral suppression as a viral load below 200 copies in the last measurement of the year.
The Kaiser team divided study participants by gender (87% male, 13% female) and age (under 35, 11%; 35 to 54, 57%; 55 or older, 33%). The analysis included 16,835 people in 2010, 17,738 in 2011, and 18,270 in 2012. The proportion of people 35 to 54 years old fell gradually over the 3 years (61%, 59%, 57%), while the proportion of people 55 or older rose (29%, 30%, 32%).
Proportions linked to care were significantly higher for males than females in 2010 (97.2% versus 96.2%) and 2011 (97.3% versus 96.2%), but those differences were reversed in 2013 (96.3% versus 97.1%). In contrast, retention rates were significantly lower among males than females in all three study years (77.8% versus 81.6% in 2010; 79.4% versus 82.4% in 2011; 79.2% versus 84.6% in 2012).
Males filled antiretroviral prescriptions significantly more often than females in 2010 (66.6% versus 64.0%) and 2011 (70.0% versus 67.0%) but not in 2012 (70.7% versus 70.5%). Higher proportions of males than females attained virologic suppression in 2010 (61.7% versus 56.0%) and 2011 (65.6% versus 59.5%). But that difference lost significance in 2012 (66.5% versus 64.6%).
Increasing age did not significantly affect linkage to care in any study year. But the 55-plus group maintained significantly greater rates of retention in care (84.5% versus 84.2% at 35 to 54 versus 77.4% under 35 in 2012), antiretroviral prescriptions (75.6% versus 74.3% versus 62.9% in 2012), and viral suppression (72.3% versus 64.7% versus 56.5%).
Retention in care, ART prescription, and viral suppression below 200 copies improved every year in both genders and all three age groups. The Kaiser investigators suggested four factors that may explain those improvements: (1) multidisciplinary care teams, (2) electronic health records shared by team members, (3) continual quality measurement and quality improvement, and (4) high antiretroviral adherence rates.
The researchers stressed that success along the care cascade differed by age and gender even in an integrated healthcare system in which everyone has equal access to care. But gender-based differences generally declined over time. They proposed that stratified cascade analyses like this "can help identify subpopulations requiring more targeted outreach." They called for further analyses by race and HIV transmission group. For the Kaiser population, the researchers emphasized the need for programs targeting younger people with HIV.
1. Horberg M, Hurley L, Klein D, et al. The HIV care cascade measured over multiple time periods varies by age and gender. IDWeek 2014. October 8-12, 2014, Philadelphia. Abstract 88.
2. Centers for Disease Control and Prevention. CDC fact sheet: HIV in the United States: the stages of care. 2012. www.cdc.gov/nchhstp/newsroom/docs/HIV-Stages-of-Care-Factsheet-508.pdf