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  • A Canadian study monitored more than 1,400 women living with HIV.
  • Nearly 30% of women diagnosed with HIV did not achieve viral suppression.
  • Some groups of women had greater challenges with adherence and staying in care.

Studies of people who are starting HIV treatment (ART) have found that when ART is taken as directed for several months the amount of HIV in the blood usually falls to very low levels (commonly referred to as an undetectable viral load). Continued use of ART keeps HIV suppressed and studies have found that the health of the immune system gradually improves and the risk of AIDS-related infections and cancers is significantly reduced. The impact of ART is so profound that researchers increasingly expect that many ART users will have a near-normal life expectancy. Studies have also found that ART users who achieve and maintain an undetectable viral load do not pass on HIV during sex.

These twin benefits of ART are so tremendous that the Joint United Nations Program on AIDS (UNAIDS) and the World Health Organization (WHO) have encouraged countries, regions and cities to achieve the following goals by the year 2020:

  • 90% of people with HIV know their infection status
  • 90% of people diagnosed with HIV have received an offer of and are taking ART
  • 90% of ART users have an undetectable viral load

These goals are commonly called “90-90-90.”

The movement of people from HIV testing through taking ART and achieving an undetectable viral load has been given several names by different researchers: the cascade of care, the HIV cascade of care or, simply, the cascade. The term 90-90-90 shortens and idealizes what is, in reality, a complex flow of people in and sometimes out of the healthcare system.

Achieving 90-90-90 is an important step to improving and maintaining the health of HIV-positive people. Many countries, regions and cities are assessing their populations’ flow at every step in the cascade. The idea of a cascade of care is meant to be used as a tool to measure overall progress in care and treatment.

In Canada, some sub-populations are at heightened risk of HIV infection. The Canadian HIV Sexual and Reproductive Health Cohort Study (CHIWOS) has been examining issues related to the flow of women through the cascade. CHIWOS has recruited more than 1,400 HIV-positive women. Extensive interviews with these women have captured information about their health and well-being that is very useful. CHIWOS researchers have found that, overall, nearly 30% of women fell out of the cascade. Furthermore, when CHIWOS researchers assessed different points in the cascade, they found that different sub-groups of women faced barriers to staying in care and achieving good health. The latest report from CHIWOS describes some of these barriers and urges health systems to develop focused interventions to help HIV-positive women stay in the cascade.

Study details

CHIWOS has enrolled 1,424 women. The present analysis focused on the initial or baseline data that were collected when women entered the study between August 2013 and May 2015. Researchers recruited women through several means—word of mouth, referrals from care providers, online networks of women, AIDS service organizations, community health centres, shelters, food banks and other settings.

To help enhance the capture of information, CHIWOS recruited peer research associates who interviewed the women in person (at HIV clinics, their homes or a mutual meeting place) or via telephone or Internet. Women were asked about a wide range of issues that affected their health and well-being. Also, researchers assessed the women’s resiliency (through a scoring system) toward adverse events in their lives.

The average profile of participants upon entering the study was as follows:

  • age – 43 years
  • 4% of women identified as transgender
  • geographic distribution – 50% of participants lived in Ontario; 25% in B.C.; 25% in Quebec
  • major ethno-racial groups: white – 41%; African/Caribbean/Black – 29%; Indigenous – 22%
  • years living with HIV – 11
  • 37% of women had a history of being imprisoned
  • 18% of women reported currently injecting street drugs and 27% disclosed past but not current injection drug use

Steps in the cascade

For the purposes of the present study, CHIWOS defined the cascade as follows:

  • received an HIV diagnosis
  • linked to care (referred to a doctor)
  • retained in care (having seen a doctor and made further appointments in the past year)
  • initiated ART
  • currently taking ART
  • adherent to ART (taking at least 90% of ART doses in the past month)
  • achieved viral suppression (having a viral load less than 50 copies/mL)


Here is the distribution of women at different points in the cascade:

  • linked to care – 98% of women
  • retained in care in the past year – 96%
  • initiated ART – 88%
  • currently taking ART – 83%
  • adherent to ART – 68%
  • achieved viral suppression – 72%

According to the researchers, the apparent discrepancy of 68% of women being adherent but 72% achieving viral suppression is likely due to the fact that some women “still took enough of their monthly doses of [ART] to achieve viral suppression.”

Overall, the figure of 72% of women achieving an undetectable viral load shows that progress is being made toward the 90-90-90 targets. However, this figure masks issues within sub-groups of women, as explored below.

Falling out of the cascade

The researchers found the following issues relevant in explaining why some women fell out of the cascade of care.


The researchers stated: “Women reporting older age, longer duration with HIV and [who were generally more resilient] had reduced odds of [falling out] of any stage of the cascade.” The researchers found that age, as a factor, had the “strongest effect early in the cascade.” Specifically, younger women were more likely to fall out of the cascade than older women.

Ethno-racial groups

The researchers found that women of African/Black or Caribbean descent were more likely to be virally suppressed (84%) than white women (71%). In comparison, Indigenous women had the lowest overall rate of viral suppression (57%) and were more likely to fall out of the cascade than women from other ethno-racial groups.

Substance use

Women who currently injected street drugs were less likely to be adherent to ART compared to women who did not inject street drugs. The researchers also found that women who engaged in problematic drinking (so-called “binge drinking” or “heavy drinking”) in the past month were significantly less likely to be adherent to ART.


Researchers found that imprisonment had a significant impact on women in the latter stages of the cascade. For instance, women who had been imprisoned in the past year were three-fold more likely to be non-adherent than women who had not been imprisoned and had nearly a four-fold risk of not achieving an undetectable viral load.

Unstable housing

Women whose housing situation was unstable were five-fold more likely to drop out of the early stage of the cascade of care. The researchers stated that women with unstable housing were at heightened risk for “not initiating or currently taking ART.”

Helping women

The latest analysis from CHIWOS has revealed that while overall progress toward meeting the UNAIDS/WHO goals of 90-90-90 is being made, there are some sub-groups of women who are at elevated risk of falling out of the cascade of care. Below are some of the proposed solutions by the researchers.


The researchers found that younger women were more likely to fall out of the cascade of care. The researchers noted that “standard healthcare services have traditionally experienced difficulties engaging youth living with chronic disease. However, engagement may be particularly difficult for youth living with HIV. [Previous] research has found that HIV stigma, mental health, substance use, lack of youth-focused interventions and unstable housing were important barriers to HIV care and treatment among youth.” In order to remedy the present situation with young women, the researchers stated that “there is an urgent need to identify gender-specific interventions for this group.”


The researchers stated that their findings “strongly suggest that there is a need for increased culturally competent, culturally safe, and violence- and trauma-aware HIV care in Canada. Inviting Indigenous women living with HIV to the planning and delivery of such care is essential.”

Substance use

To improve the health of women who use substances, the researchers stated: “Given that 21% of all [new] HIV infections among women in Canada are attributable to injection drug use and that 45% of women in [CHIWOS] report a history of injection drug use, there is a clear need to incorporate evidence-based, gender-specific, trauma-aware, low-barrier harm-reduction services and addiction care within women’s HIV care.”


The researchers stated that women who had been recently imprisoned had the highest overall rate of dropping out of the cascade. They advanced the following explanation: “[Imprisonment] represents a highly traumatic, stressful, and chaotic time for women living with HIV. This disruption often extends for months before and after the period of incarceration. While incarcerated, women may choose not to disclose their HIV status due to fear of stigma or violence, and, after disclosure, ART interruptions are routine.” To improve the health of these women, the researchers recommended: “High-quality, confidential HIV care, ideally linked to mental health and addiction services, should be available for all women with incarceration experience.”

Unstable housing

A previous study also found that unstable housing is associated with falling out of the HIV care cascade. CHIWOS researchers stated: “Further efforts to address housing for marginalized women are needed.”

Enabling the strengths of women

In CHIWOS, women who had higher resiliency scores were more likely to move through the cascade and achieve viral suppression. This finding suggests that improving the resiliency of HIV-positive women is likely useful in maintaining or improving their overall health and HIV-related care. The researchers noted that in San Francisco the Medea Project has been successfully deployed to help HIV-positive women “develop social support, self-esteem…and seek safer and healthier relationships.” The researchers suggested that, in general, “trauma-informed interventions that focus on mindfulness and cognitive behavioural therapy have proven beneficial for women living with HIV, particularly those with comorbid post-traumatic stress disorder and substance use, and should be evaluated for their impact on resilience.”

The importance of CHIWOS

This latest analysis from CHIWOS is extremely important. It shows that if progress toward achieving 90-90-90 is to be made in Canada, more resources need to be mobilized to improve the care and treatment of women living with HIV so that they stay in and move forward in the cascade.

Minor shortcomings

Like every other study, CHIWOS is imperfect. The women who entered it were not randomly chosen; women who were more likely to have/had issues in their lives may have been inadvertently selected. Yet, despite the lack of randomization, CHIWOS has recruited women who are representative of the HIV epidemic in Canada.

It is possible that some women may have understated some of their issues to appear more appealing to researchers (this is called “social desirability bias”). However, CHIWOS recruited peer researchers to engage with participants in interviews, a factor that likely would have reduced the issue of social desirability bias.

So far, the data from CHIWOS was collected from each woman at one point in time; this leads to cross-sectional analyses. However, CHIWOS is in the process of collecting data over time and therefore will become a longitudinal study, which will further enhance its usefulness.


Longer life expectancy for HIV-positive people in North AmericaTreatmentUpdate 200

Exploring factors linked to longer survival among ART usersTreatmentUpdate 200

90-90-90: An ambitious treatment target to help end the AIDS epidemic – UNAIDS

Comparing substance use patterns among women in CanadaCATIE News

Canadian researchers call for improved integration of family planning care for HIV-positive womenCATIE News

The Women of CHIWOSPositive Side magazine


The Medea Project

Summary: Estimates of HIV incidence, prevalence and Canada’s progress on meeting the 90-90-90 HIV targets, 2016 – Public Health Agency of Canada (PHAC)

HIV in Canada – PHAC infographic

—Sean R. Hosein


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