(VP097) SEVERITY OF ILLNESS IN INDIGENOUS PATIENTS WITH PULMONARY ARTERIAL HYPERTENSION IN CANADA

Background: Recent observational studies of patients with pulmonary arterial hypertension (PAH) demonstrate that clinical outcomes vary by ethnicity in the United States. There is limited data on outcomes in Indigenous populations in Canada, a demographic that has been historically and structurally marginalized and underrepresented in clinical research.

METHODS AND RESULTS: We used our large pulmonary hypertension (PH) registry to evaluate severity of illness on presentation for Indigenous vs. non-Indigenous patients, as determined by baseline right heart catheterization (RHC). Patient ethnicity was determined by self-report. We included all patients who carried a diagnosis of PAH as defined as a mean PA pressure of >20 mmHg, a wedge pressure of < 15 mmHg and a pulmonary vascular resistance of > 3 WU. Parameters evaluated included the mean PA pressure (mPAP), the cardiac index (CI), the pulmonary vascular resistance (PVR), and the mean right atrial pressure (mRAP). This was a collaborative study done in consultation with members of several nations residing in British Columbia and Alberta. Of the 425 patients identified with a diagnosis of PAH, 41 patients were of Indigenous background whereas 384 patients were non-Indigenous. Indigenous patients were younger (50.8±13.5 vs. 58.5±15.3 yrs, P=0.002), and more likely to be female (90.2% vs. 72.7%, P=0.01). At the time of PH diagnosis, baseline RHC measurements showed a higher median mPAP (50 [interquartile range (IQR) 44-54] vs. 44, [IQR 35-52] mmHg, P=0.03) and a higher median PVR (9.5 [IQR 6.5-13.8] vs. 7.9 [IQR 4.8-11.3] WU, P=0.06) for patients of Indigenous background compared to non-Indigenous patients, respectively. There was no clinical significance between the median mRAP and CI between both groups.

Conclusion: We found that patients of Indigenous background had higher median mPAP and PVR values on baseline RHC at the time of diagnosis compared to non-Indigenous patients. This suggests that Indigenous patients tend to be diagnosed with PH at a more advanced stage with greater disease severity than non-Indigenous populations. In-depth evaluation of the barriers to PH screening and access to care are urgently needed in this population.