Primary aldosteronism driving hypertension risk in the Top End


19 Sep 2023

New research from the Northern Territory has unearthed worrying rates of primary aldosteronism in young Indigenous people, prompting calls for a screening program across the Top End.

The research, including some 331 participants, found screening test results for the condition were positive for about one-quarter of urban Indigenous and non-Indigenous participants, with concerning results found in both urban and remote locations.

All aged between 32 and 35 during the study, the participants came from two groups: The Aboriginal Birth Cohort (ABC), comprising individuals born to Indigenous mothers at the Royal Darwin Hospital between 1987–1990, and the Top End Cohort (TEC), which included those born to non-Indigenous mothers in Darwin from 2007–2009.

The central outcome measures were plasma aldosterone and direct renin concentrations, as well as aldosterone-to-renin ratios (ARRs), which can indicate a positive screening result for primary aldosteronism when greater than 70 pmol/mU.

The researchers, led by senior author Associate Professor Jun Yang from the Hudson Institute of Medical Research, found that while the median aldosterone concentration was consistent across the groups, screening ARR values exceeded 70 pmol/mU for 26% of urban Indigenous participants and 28% of non-Indigenous participants.

However, a larger ARR was linked to higher systolic blood pressure within the TEC group but not in the ABC groups.

The findings also highlighted gender-based differences in hypertension rates, with women generally having lower blood pressure levels than men across all groups when adjusted for age and body mass index (BMI).

Associate Professor Yang, who had previously identified primary aldosteronism as a major contributor to hypertension, said there was a concerning lack of data on the condition in Australian Indigenous communities.

“Australian First Nations people are known to have high rates of hypertension and cardiovascular disease, but this is the first time this type of testing has been done in these communities,” she said.

“Primary aldosteronism is a highly modifiable risk factor for cardiovascular disease and correct identification will enable appropriate targeted treatment.”

The next step was to establish a process of appropriate screening process across the Top End, according to the authors.

“Following up people with positive primary aldosteronism screening results and determining the relationship between the ARR and future blood pressure levels would be beneficial,” they noted in the MJA (link here).

“Indigenous Australians should have the same access to primary aldosteronism screening and diagnosis as other Australians, as this condition may compound the effects of other cardiovascular risk factors for Aboriginal and Torres Strait Islander people.”

“A prospective study employing the complete primary aldosteronism diagnosis pathway could better determine its prevalence among Indigenous Australians.”

The aldosterone and renin test kits used in the study were provided by pharmaceutical company DiaSorin.

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