Cardiovascular dynamics of Canadian Indigenous peoples

Modelling prevalent cardiovascular disease in an urban Indigenous population

OBJECTIVE

Studies have highlighted the inequities between the Indigenous and non-Indigenous populations with respect to the burden of cardiovascular disease and prevalence of predisposing risks resulting from historical and ongoing impacts of colonization. The objective of this study was to investigate factors associated with cardiovascular disease (CVD) within and specific to the Indigenous peoples living in Toronto, Ontario, and to evaluate the reliability and validity of the resulting model in a similar population.

METHODS

The Our Health Counts Toronto study measured the baseline health of Indigenous community members living in Toronto, Canada, using respondent-driven sampling. An iterative approach, valuing information from the literature, clinical insight and Indigenous lived experiences, as well as statistical measures was used to evaluate candidate predictors of CVD (self-reported experience of discrimination, ethnic identity, health conditions, income, education, age, gender and body size) prior to multivariable modelling. The resulting model was then validated using a distinct, geographically similar sample of Indigenous people living in Hamilton, Ontario, Canada.

RESULTS

The multivariable model of risk factors associated with prevalent CVD included age, diabetes, hypertension, body mass index and exposure to discrimination. The combined presence of diabetes and hypertension was associated with a greater risk of CVD relative to those with either condition and was the strongest predictor of CVD. Those who reported previous experiences of discrimination were also more likely to have CVD. Further study is needed to determine the effect of body size on risk of CVD in the urban Indigenous population. The final model had good discriminative ability and adequate calibration when applied to the Hamilton sample.

CONCLUSION

Our modelling identified hypertension, diabetes and exposure to discrimination as factors associated with cardiovascular disease. Discrimination is a modifiable exposure that must be addressed to improve cardiovascular health among Indigenous populations.

The representation of Indigenous peoples in chronic disease clinical trials in Australia, Canada, New Zealand, and the United States

BACKGROUND

Indigenous peoples are overrepresented with chronic health conditions and experience suboptimal outcomes compared with non-Indigenous peoples. Genetic variations influence therapeutic responses, thus there are potential risks and harm when extrapolating evidence from the general population to Indigenous peoples. Indigenous population-specific clinical studies, and inclusion of Indigenous peoples in general population clinical trials, are perceived to be rare. Our study (1) identified and characterized Indigenous population-specific chronic disease trials and (2) identified the representation of Indigenous peoples in general population chronic disease trials conducted in Australia, Canada, New Zealand, and the United States.

METHODS

For Objective 1, publicly available clinical trial registries were searched from May 2010 to May 2020 using Indigenous population-specific terms and included for data extraction if in pre-specified chronic disease. For identified trials, we extracted Indigenous population group identity and characteristics, type of intervention, and funding type. For Objective 2, a random selection of 10% of registered clinical trials was performed and the proportion of Indigenous population participants enrolled extracted.

RESULTS

In total, 170 Indigenous population-specific chronic disease trials were identified. The clinical trials were predominantly behavioral interventions (n = 95). Among general population studies, 830 studies were randomly selected. When race was reported in studies (n = 526), Indigenous individuals were enrolled in 172 studies and constituted 5.6% of the total population enrolled in those studies.

CONCLUSION

Clinical trials addressing chronic disease conditions in Indigenous populations are limited. It is crucial to ensure adequate representation of Indigenous peoples in clinical trials to ensure trial data are applicable to their clinical care.