20 May 2014 

Alberta—Reducing deaths by strengthening the HIV Treatment Cascade

In Canada and other high-income countries, deaths from AIDS-related illnesses have decreased dramatically since the arrival of potent combination anti-HIV therapy (commonly called ART or HAART) in the mid-to-late 1990s. The benefits of ART are so tremendous that researchers in high-income countries expect that young adults who become infected today and who are diagnosed and begin treatment shortly thereafter and are engaged in their care and who do not have serious co-existing health issues are likely to live into their 70s.

At the level of a large city or region

When taken every day, exactly as directed, ART not only improves a person’s health but it also significantly reduces the amount of HIV in the blood and genital fluids. This latter effect can greatly help to reduce the further spread of HIV in a city or region.

The spectrum of care

For the widespread use of ART to significantly reduce the spread of HIV, people who test positive must have timely and barrier-free access to the medical-healthcare system so that their needs are met. There are many steps that need to happen between getting counselling, HIV testing, starting ART and reaching and maintaining the goal of a low viral load. These steps reflect the spectrum of care and are also called the HIV Treatment Cascade, or simply the Cascade of Care.

Here are some of the steps (greatly simplified) and gaps that can occur in the HIV Treatment Cascade:

  • Counselling and screening for HIV
  • Returning for the test result and counselling
  • Agreeing to be referred to a doctor with the skills and knowledge to care for people with HIV
  • Being referred for care after counselling and HIV diagnosis but not visiting the health clinic
  • Attending an initial clinic visit but not having blood drawn for immunologic and virologic assessments
  • Attending an initial clinic visit, having blood drawn and making subsequent clinic visits (retained in care)
  • Being retained in care but not taking ART
  • Being retained in care, initiating ART but being unable to have viral load fall below the lower limit of quantification—usually either 50 copies/ml or 40 copies/ml depending on the test available to local labs; viral loads that are below this threshold are commonly called undetectable
  • Being retained in care, initiating ART and achieving a low viral load

More focus is being paid to the HIV Treatment Cascade as researchers realize that gaps in the Cascade impair a person’s health and contribute to the spread of HIV. Studies of the HIV Treatment Cascade belong to an emerging field of research called Program Science.

Unsuccessful engagement with the HIV Treatment Cascade can have serious health implications at the individual level, as researchers in Alberta have recently documented. In that province, a team of researchers has been monitoring what happened to 543 newly diagnosed people with HIV. They have found issues in the HIV Treatment Cascade such as the following:

  • apparent lack of referral for care after an HIV diagnosis
  • despite referrals nearly 18% of newly diagnosed people never visited a clinic to receive care and treatment
  • at least 36 people died and 70% of these deaths were HIV related
  • most deaths occurred in people who did not remain in care

This focus on deaths arising from falling out of the Cascade is novel and important because it means that fixing the gaps in the Cascade has the potential to save lives. The Alberta study is a good first step toward documenting the consequences of problems with the Cascade. Further investigation is needed to capture and understand the reasons for some people’s disappearance from care and to find ways to narrow gaps in the Cascade, not only in Alberta but in other regions.

Study details

The Southern Alberta HIV Clinic in Calgary is a major regional treatment centre. People who test positive for HIV in the region are referred to this clinic. Researchers focused on the following outcomes related to the HIV Treatment Cascade:

  • diagnosed with HIV but never referred (or linked) to care
  • referred for HIV care but never visited the HIV clinic
  • made a first visit to the clinic for counselling and registration for care but never made a subsequent visit
  • continued to make clinic visits (retained in care) but did not take ART
  • retained in care and took ART but did not achieve a low viral load (less than 40 copies/ml)

The first visit to the clinic helps nurses and social workers develop a relationship with the patient. The clinic staff provides psychosocial support and education about HIV and its treatment, as well as answering questions that the patient might have. After completing the counselling and intake process, the patient provides blood for immunologic and virologic assessment.

The Alberta researchers also had access to public health, provincial and clinic databases so they were able to keep track of patients as they moved through the Cascade.

Results—New infections

During the study period—2006 to 2013—there were 543 new and confirmed cases of HIV infection.

The researchers stated that “overall 12% (65 people) of new HIV diagnoses occurred shortly before, during or shortly after [less than a week of] hospitalization.”

Note that the Public Health Agency of Canada (PHAC) estimates that approximately 25% of people in Canada who have HIV are not aware of their infection status. Based on this figure, the Alberta researchers calculated that there were likely an additional 137 cases (25% more) of HIV during their study, for a total of 680 confirmed and estimated new infections. However, in our report we will focus on the 543 confirmed cases of new HIV infections.

Results—From test result to the clinic

The researchers found the following:

  • 500 people (92%) of known new cases of HIV were referred for care to the clinic
  • 43 people (8%) of newly diagnosed cases and who were known to the regional Public Health Department were not referred for care (possible reasons for this are explored later in this report)

Results—In the clinic

412 people (82% of 500) who were referred to the clinic remained in care. These 412 people represented 76% of the confirmed new infections and they were monitored for an average of five years. Additionally, among the patients in care, the proportions on ART and having a low viral load were as follows:

  • most patients (88%) received ART
  • 76% of patients on ART had a viral load less than 40 copies/ml by the end of the study

Researchers gave the following reasons for those patients not on ART:

  • they had a high CD4+ cell count
  • they had a viral load less than 40 copies/ml
  • it was the patients’ own personal choice

Distribution and causes of death

The researchers noted that a total of 36 deaths occurred among people diagnosed with HIV during the study. They stated that “only one death occurred [among new cases of HIV] that was not linked to care in any form.” This single case was only recognized to have HIV after death.

The remaining 35 deaths occurred in people who at one time had been linked to care but did not remain in care. Here are further details about those deaths:

  • 57% (20 of 35 deaths) occurred in people who were referred to or connected to the clinic but did not make regular visits to the clinic. These people did not receive ART and in some cases did not have their blood drawn for immunologic and virologic assessment.
  • 70% of these 20 deaths (14 of 20 people) were AIDS-related
  • six of these 20 deaths occurred in people who were hospitalized.

Five of the 14 deaths that occurred outside of hospitalization were among patients who had an initial clinic visit to meet with a nurse or social worker but who did not return for their first appointment with a physician.

Deaths in care

Among participants who were in care (and who stayed in care), only one person died without having ever received ART. According to the study team, he chose not to initiate therapy. Five of 14 people who died initially received ART; however, prior to their death they had stopped taking ART. In four of these five cases, participants chose to discontinue taking ART.

Researchers found that people who died while in care were more likely to have the following profile compared to people who survived:

  • low CD4+ counts (63 cells vs. nearly 300 cells)
  • an additional pre-existing illness or co-morbidity (46% vs. 14%)
  • HIV risk factor was sharing equipment for injecting street drugs (27% vs. 7%)
  • older at the time of HIV diagnosis (47 years vs. 37 years)


In the present study, over a period of six years, 92% of newly diagnosed HIV cases were linked to care. However, only 58% of people who began ART eventually had their viral load fall below the 40-copy/ml mark.

These figures are disappointing and are “likely lower than needed to significantly impact [the spread of HIV in Southern Alberta],” the researchers stated.

Importantly, the researchers noted that they also found that “a significant proportion of deaths occurred after initial linkage [to a clinic] but before full engagement to care.”

The researchers advanced the following reasons that patients were not able to link to care:

  • in cases of HIV testing, some people may not have returned to receive their results and their physician or Public Health department was unable to contact them
  • patients may have ignored the positive test result
  • some patients may have moved and could not be found

Additional research is needed about these and other reasons that patients fall out of the medical-healthcare system. Clues about this may come from another study by the U.S. Centres for Disease Control and Prevention (CDC).

The Never in Care Study

The CDC has also been concerned about people who do not connect with the healthcare system after a positive HIV test result. As part of an investigation called the Never in Care Study, the CDC found that contacting people who test positive for subsequent interviews is a problem because it can be difficult to locate them. In particular, the CDC and public health officials cited the following reason:

  • Contact information obtained at the time of HIV diagnosis was “frequently incorrect.”

Furthermore, even when researchers were able to locate people, nearly 30% refused to be interviewed.

Among 132 people who had been diagnosed with HIV within the past four to 24 months and who consented to be interviewed by the CDC as part of a study, here are some of the reasons that they gave for not entering care:

  • 55% – not wanting to think about HIV
  • 55% – feeling healthy
  • 45% – feeling depressed
  • 43% – not wanting to disclose their HIV status

According to the CDC researchers, most participants gave multiple reasons for not entering care. The CDC concluded that “poverty and mental health problems may be contributing factors, underscoring the importance of supportive services to help with starting and staying in care.”

Several studies examine gaps in care

Researchers in BC have also documented gaps in the HIV Treatment Cascade. The Alberta study has extended the BC findings by highlighting the serious consequences that such gaps pose to people living with HIV. These gaps show that receipt of a positive HIV test result is not necessarily followed by linkage to care, retention in care and successful use of ART. The results from Alberta and BC will hopefully encourage researchers in other regions of Canada to investigate and publish their findings of the HIV Treatment Cascade. By uncovering gaps in the Cascade, researchers can underscore the need for resources to be applied to the spectrum of care so that gaps can be closed, the health of HIV-positive people can improve, and the spread of HIV in Canada can be greatly diminished.


Gaps in British Columbia’s HIV Treatment CascadeCATIE News

The HIV Treatment Cascade – patching the leaks to improve HIV preventionPrevention in Focus

Treatment as prevention: Do the individual prevention benefits translate to the population level?Prevention in Focus


We thank infectious disease specialist John Gill, MD, for his helpful review, discussion and research assistance.

                                                                                                                                                                —Sean R. Hosein


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