Patients are being
lost at each stage of the HIV care ‘cascade’ in British Columbia, Canada.
Investigators from the STOP HIV/AIDS Study group examined data from 1996 to 2011
and estimated the proportion of people engaged with HIV care at each stage of
the care continuum, from diagnosis through to viral suppression. Their findings,
published in The Lancet Infectious Diseases,
show that engagement with care improved steadily over the 15 years of the
study. However, there was significant attrition at each stage of the care
cascade, and in 2011 only 35% of HIV-positive people had an undetectable
HIV treatment and
care are free in British Columbia (unlike other states in Canada), and the investigators suggest their results “are thus
likely to represent a best-case scenario, in which individuals are not subject
to financial disincentives and state-of-the-art antiretroviral management is
consistently recommended and available”.
The authors of an editorial in the
same issue of the journal believe “structural factors embedded in health care
systems and stigma and discrimination” are likely explanations for the
attrition recorded at each step of the care continuum.
effective antiretroviral therapy first became available in 1996. Its
introduction was accompanied by immediate reductions in rates of serious
illness and death among people with HIV. The goal of treatment is suppression
of viral load to undetectable levels, thus allowing the immune system to
strengthen. There have been significant improvements in HIV treatment and care
since 1996. People in resource-rich settings – such as Canada – who are doing well on antiretroviral therapy
now have a normal life expectancy. Virally suppressive HIV treatment also has another
important benefit, significantly reducing the risk of onward transmission of
number of people are not benefiting from treatment. Studies from around the
world consistently show that a large proportion of HIV-positive individuals are
undiagnosed. Moreover, a significant proportion of diagnosed people are not successfully
linked to or retained in care, and many do not start or adhere to antiretroviral
Efforts to reduce
the rate of undiagnosed infections and improve engagement with care have
become central to strategies to maximise individual and public health benefits
of HIV treatment.
the STOP HIV/AIDS Study Group wanted to map changes in engagement
with care between 1996 and 2011.
They defined eight
stages in the care continuum:
- Infection with HIV.
- Linkage to care.
- Retention in care.
- Antiretroviral treatment
- On HIV therapy.
- Adherent to antiretrovirals.
- Undetectable viral load.
regarding the proportion of people engaged in the care continuum were based
on sources including province-wide HIV prevalence estimates and population-level
A total of 13,140
individuals were diagnosed with HIV over the course of the study. The
proportion of HIV-infected population with diagnosed infection increased from
51% in 1996 to 71% in 2011.
was significant attrition at each stage in the care continuum. For instance, the
proportion of people linked to care was 4% to 10% lower than the proportion
diagnosed with HIV. Rates of retention in care lagged behind linkage, reaching
a high of 81% in 2011. The proportion of patients indicated for and receiving
HIV therapy was close to that retained in care. Among the people taking
antiretroviral treatment, the proportion who were adherent to their therapy
increased from 76% in 2003 to 87% in 2011.The percentage of people with an
undetectable viral load increased from just 0.7% in 1996 to 14% in 2000, and to
35% in 2011.
substantial improvements in the proportions of people diagnosed, on HAART
[highly active antiretroviral therapy], and virologically suppressed,” write
the authors. They attribute these gains to increased testing, changes in
guidelines concerning the initiation of antiretroviral treatment, improvements in HIV
care, and the introduction of more potent and tolerable anti-HIV drugs.
of the cascade of care is crucial to improve our understanding of how to
maximise the beneficial effects of available interventions and to inform
efforts to contain the spread of HIV/AIDS,” conclude the authors. “A
high-quality HIV surveillance system actively linked to relevant administrative
health records is essential for such endeavor.”
The authors of the
accompanying editorial argue that “the various cascade steps can jeopardize the
health outcomes of many people.” Therefore, it is “important for jurisdictions
to develop metrics of treatment cascades and population-based HIV viral load
assessments”. They believe the British Columbia study is “an excellent example
of the utility of reviewing cascades over time. We look forward to seeing more
examples of longitudinal cascade evaluations in the future; shared successes
will hopefully help the global community improve the global cascade of HIV