July/August 2018 

Co-morbidities in selected Canadian clinics

As all people age they become at risk for developing illness related to the decline of important organ-systems. Some people with HIV appear to be at heightened risk for such illnesses, called co-morbidities. If left untreated, co-morbidities can degrade health-related quality of life and likely shorten life expectancy.

Researchers at five HIV clinics in four provinces—British Columbia, Saskatchewan, Ontario and Quebec—collaborated on a study to review data collected from 1,000 HIV-positive people who had recently made a clinic visit.

Analysis of the data revealed that co-morbidities were common. Furthermore, nearly 75% of participants had two or more co-morbidities.

The study underscores the importance of screening for and, when necessary, offering treatment for co-morbidities.

Study details

The study was retrospective in design; that is, it reviewed data already collected for another purpose and then analysed that data.

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

  • 82% men, 18% women
  • age – 52 years
  • time since HIV diagnosis – 14 years
  • major ethno-racial groups: white – 74%; Indigenous – 12%; black – 9%; Asian – 2%; Hispanic 2%
  • currently using substances: tobacco – 37%; alcohol – 55%; recreational drugs – 37%; injecting street drugs – 13%
  • CD4+ cell count – 560 cells/mm3
  • viral load – less than 40 copies/mL
  • eGFR (estimated glomerular filtration rate; a routine measure of kidney health) – 77 mL/minute
  • hepatitis C virus co-infection – 28%


The distribution of co-morbidities among participants was as follows:

  • brain related – 53%
  • liver related – 50%
  • overweight/obesity – 43%
  • abnormal levels of fatty substances (cholesterol, triglycerides) – 37%
  • thinner-than-normal bones – 24%
  • higher-than-normal blood pressure – 24%
  • kidney injury/dysfunction – 18%
  • cardiovascular disease – 15%
  • type 2 diabetes – 9%

Only 7% of participants did not have a diagnosis of a co-morbidity.

The researchers found that almost 75% of participants had two or more co-morbidities:

  • having two co-morbidities – 26%
  • having three co-morbidities – 18%
  • having four or more co-morbidities – 30%


Bone mineral density tends to generally decline with age and thinner bones are more susceptible to fractures. Studies with HIV-positive people have found that thinner-than-normal bones are relatively common.

Researchers examined data from a subset of 199 participants in the present study who had bone density scan data and found the following:

  • 29% had normal bone density
  • 58% had moderately thin bones (osteopenia)
  • 13% had severely thin bones (osteoporosis)

Heart and kidney disease

The kidneys are rich in blood vessels, as these organs filter the blood, so conditions that affect the heart and blood vessels tend to also affect the health of the kidneys. Researchers used risk calculators that could estimate the risk for differing degrees of heart and kidney disease and found the distribution of these risks as follows:

Cardiovascular disease risk

  • low – 58%
  • medium – 38%
  • high – 10%

Kidney disease risk

  • low – 12%
  • medium – 19%
  • high – 69%

Bear in mind

In a sample of 1,000 HIV-positive Canadians taking ART, researchers found a high level of co-morbidities. Furthermore, a significant proportion of participants (nearly 70%) were at elevated risk for kidney disease and 10% were at elevated risk for cardiovascular disease.

The present study’s design was retrospective in nature and participants were not apparently chosen at random. Retrospective studies cost less than other study designs, as the work of capturing the data has already been done, and they are a good first step at exploring an issue. However, analyses of retrospective studies can sometimes inadvertently give rise to biased conclusions. Nonetheless, the research team documented the issues that were affecting patients who recently visited their doctor, and this is useful.

A different approach might have been to also assess HIV-negative people of the same age, gender and socio-economic status and compare the proportions of co-morbidities. However, such an approach would have cost much more money, been labour-intensive and taken much more time to capture data, as physicians do not normally engage with socio-economic data at the level of the individual. Different study designs have advantages and disadvantages, and these must be considered in light of available funding.

The study is important because among people whose viral loads are suppressed due to ART, co-morbidities and their risk factors are major drivers of poor health-related quality of life. If they are left untreated, co-morbidities can affect life expectancy.

For the future

The study has expanded to include data from 10 clinics, for a total of 2,000 people, and data from this larger sample is being analysed. This expanded data set would provide a good picture of common co-morbidities affecting HIV-positive people in Canada. The researchers hope to present the results of the expanded data set at a conference in 2019. The results of the final data set will be very useful and provide a rationale for other studies that monitor the health of HIV-positive people as well as interventions to help maintain or improve their health by reducing the risk or severity of co-morbidities.

—Sean R. Hosein


Fraser C, Wong A, Baril J-G, et al. Canadian HIV practice reflective initiative to improve management of patients with co-morbidities. Canadian Association for HIV Research, 26-29 April 2018, Vancouver, British Columbia. Poster CSP8.10.