US PrEP care cascade analysis suggests that major, structural barriers need to be addressed for PrEP to have an impact

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The uptake of PrEP in people who need it risks being limited due to low levels of awareness, gaps in health insurance, opaque bureaucratic procedures, under-usage of medical services, and limited awareness and skills in healthcare providers, according to an analysis published online ahead of print in Clinical Infectious Diseases. Also taking into account sub-optimal adherence among some PrEP users, the researchers conclude that just 15% of gay men in the American city of Atlanta who could benefit are likely to achieve protection from HIV with PrEP.

Colleen Kelley and colleagues at Emory University outline a ‘care cascade’ or ‘continuum of care’ for PrEP which identifies the key steps in the process of getting hold of PrEP and using it effectively. Analysis of the care cascade can help focus attention on where there are significant barriers to a person moving on to the next step.

This is similar to analyses of the antiretroviral treatment cascade – this highlights the proportion of people living with HIV who are diagnosed, linked to care, retained in care, on antiretroviral treatment and virally suppressed. Whereas some localities have problems in the early part of the cascade (e.g. people who remain undiagnosed), others have greater difficulties later on (e.g. keeping people in medical care). This helps identify where policy change is required.

The PrEP care cascade


care cascade

A model that outlines the steps of medical care that people living with HIV go through from initial diagnosis to achieving viral suppression, and shows the proportion of individuals living with HIV who are engaged at each stage. 


Social attitudes that suggest that having a particular illness or being in a particular situation is something to be ashamed of. Stigma can be questioned and challenged.

risky behaviour

In HIV, refers to any behaviour or action that increases an individual’s probability of acquiring or transmitting HIV, such as having unprotected sex, having multiple partners or sharing drug injection equipment.


In the United States, a programme providing health insurance to people on low-incomes of all ages. Provision varies from state to state, although some types of care are covered in all states.


In pharmacology, a medication which maintains its effects over a long period of time, such as an injection or implant.

To outline the care cascade in any given area, the first stage is to define an at-risk population (for example, sexually active men who have sex with men). This group is represented by the first bar on the chart that graphically represents the PrEP care cascade.

Individuals who are at-risk need to be aware of PrEP and willing to use it. The researchers note that this is changing rapidly, but knowledge of PrEP remains patchy with particular problems in some priority groups – for example, young black gay men. HIV-related stigma, poor self-assessment of risk, mistrust of the medical establishment, and concerns about PrEP’s cost and side-effects can limit willingness to use PrEP.

Individuals who want to use PrEP need to have good access to healthcare. Many of those most in need of healthcare have the least access to it, with the complex and partial system of health insurance and healthcare coverage in the United States excluding many individuals. In some cases, the cost of the drugs may be reimbursed but not the associated laboratory tests and medical visits. Some insurance policies require expensive co-payments and deductibles which can deter people from using PrEP.

For individuals to receive a PrEP prescription, individuals need to attend healthcare providers who will assess their eligibility for PrEP and be willing to provide it. However there continues to be uncertainty about which providers are best placed to prescribe PrEP and locating a skilled, informed and willing provider may be difficult. Many healthcare providers do not routinely ask questions about their patients’ sexual orientation or behaviour. Screening tools with questions about sexual behaviour may not be adapted to the local epidemiology. Healthcare providers may have concerns about adherence, ‘risk compensation’, the cost of PrEP and side-effects, or simply have little knowledge of PrEP.

For PrEP to be effective, individuals need to be adherent. Levels of adherence have varied considerably in studies, have been higher in people with high risk behaviour, but have sometimes been low in key groups such as young black gay men. 

Estimates for Atlanta

The authors then made rough estimates of what the PrEP care cascade in Atlanta could look like, based on data from a cohort of men recruited at gay venues there.

The metropolitan area of Atlanta is in the southern state of Georgia and has one of the highest burdens of HIV in the United States. Infections are concentrated in black gay men – in the cohort 6.5% of black gay men acquired HIV each year, compared to 1.7% of white gay men. Rates are especially high among younger men. HIV in Atlanta is fuelled by poverty, lack of access to healthcare and high levels of stigma. Georgia has not expanded Medicaid coverage under Obama’s health reforms, meaning that access to healthcare remains poor.

The PrEP cascade in Atlanta:

  • All HIV-negative members of the cohort are considered to be at risk.
  • 50% of the cohort say they are aware of PrEP and willing to use it, which is within the (wide) range reported by other studies.
  • 86% of the cohort have health insurance or other health coverage.
  • 69% of the cohort would be eligible for PrEP under CDC guidelines.
  • 51% of those receiving PrEP were estimated to be likely to adhere to it, based on that observed in the iPrEx Ole study.

Putting all these estimates together into the PrEP continuum, only 15.2% of Atlantan gay men would reach the last step – being sufficiently adherent to PrEP to be protected against HIV. Fewer black gay men (12.3%) than white gay men (17.8%) would reach this step.  

The authors acknowledge that this is a rough estimate and the assumptions could be refined. In particular, whereas multiple barriers could prevent someone moving along the continuum, only a single barrier was considered for each stage. For example, ability to get PrEP was estimated only by fitting the CDC’s eligibility criteria for PrEP. However, not disclosing sexual orientation, having a poorly informed medical provider and several other factors would also have an impact.

Other factors, such as the population’s awareness of PrEP, may improve as time goes on. With this in mind, the authors scaled up each estimate by 20%. The cumulative effect was for 44.3% of the cohort to be protected by PrEP.


“Even with generous, optimistic estimates, few Atlanta MSM will achieve protection from HIV with PrEP given significant barriers currently in place,” Colleen Kelley concludes. “Large, sustained changes are needed to achieve levels of HIV protection that might alter the course of the epidemic.”

Changes the authors suggest include media awareness campaigns; community interventions to destigmatise PrEP; making PrEP free to people without health insurance; centralised provision of PrEP; education and training for healthcare providers; electronic tools to assess sexual risk and PrEP eligibility; improved adherence counselling; and long-acting, injectable PrEP to improve adherence.

Novel strategies to deliver PrEP are suggested: “This should include free or low cost open access PrEP programs targeted to those at highest risk,” including delivery at services already used by gay men.

In an editorial commenting on the paper, Ken Mayer and Douglas Krakower note that uptake of PrEP has been higher and is rising in Boston and San Francisco. Both are environments that have supported civil equality for sexual and gender minorities, have culturally sensitive health services and which were early to implement health reform.

“However the findings from Atlanta study suggest that the challenges posed by unsupportive health insurance environments may become one of the major impediments remaining for PrEP to be scaled up at a sufficient level to radically decrease the number new HIV infections across the United States,” they write.


Kelley CF et al. Applying a PrEP Continuum of Care for Men who Have Sex with Men in Atlanta, GA. Clinical Infectious Diseases, online edition, 2015. doi: 10.1093/cid/civ664

Mayer KH & Krakower DS. If PrEP decreases HIV transmission, what is impeding its uptake? Clinical Infectious Diseases, online edition, 2015. doi:10.1093/cid/civ665