Mystery of high PAH rates in the red centre

While much less common than other cardiovascular disease, pulmonary hypertension may also be contributing to the gap in life expectancy between Indigenous and non-Indigenous Australians.

An observational study of 183 people diagnosed with pulmonary hypertension in Central Australia between 2005 and 2016 found the median age of diagnosis was 52 years – almost 20 years younger than in other reported cohorts.

The median age of diagnosis in Indigenous patients, who comprised 81% of the cohort, was 49 years compared to 64 years in non-Indigenous patients.

“The majority of ATSI individuals were diagnosed under 60 years of age compared to a minority of non-ATSI individuals (73% vs 35%, p <0.001),” the study said.

The overall prevalence of any type of pulmonary hypertension in Central Australia was found to be 385 per 100,000 but significantly higher in ATSI than non-ATSI patients (723 vs 126 per 100,000).

The researchers said the prevalence appeared to reflect increases in all subgroups of pulmonary hypertension.

The majority of patients (63%) had PHT due to left heart disease, 16% due to lung disease, 12% of unknown cause, 7% had pulmonary arterial hypertension (PAH), and just one patient (0.54%) had chronic thromboembolic pulmonary hypertension.

The median estimated pulmonary artery pressure (ePASP) was significantly higher in PAH patients than other patient groups and increasing ePASP was significantly associated with increasing mortality.

Increasing age was the only other association with mortality. Median survival from diagnosis was nine years.

Dr Kawa Haji, from the cardiology department at Western Health’s Sunshine Hospital in Victoria, told the limbic the high rate of pulmonary hypertension due to left heart disease was driven by the prevalence of rheumatic heart disease in Indigenous Australians.

However the data could not explain the high rates of PAH – 27 per 100,000 – which were mostly (85%) in Indigenous patients and at an even earlier age than the other types of PHT.

“PAH is more common in Indigenous people but I don’t think we have a clear answer to that. Like every other health gap issue, the problem is not straightforward. There are always multiple issues to be addressed including early diagnosis, diagnosing other diseases early and early intervention.”

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