Gender differences in rates of percutaneous coronary intervention, cardiac surgery and valvular disease in indigenous Australians with suspected acute coronary events

Background

Indigenous populations globally have a higher burden of cardiovascular disease and increased mortality after acute coronary events, partly due to inequitable access to specialised care like cardiac catheterisation. Gender differences in revascularisation rates have been well described in non-Indigenous patients. Whether this applies to Indigenous patients when cardiac catheterisation facilities are readily available is unclear.

Purpose

We compared the rates of percutaneous coronary intervention (PCI), cardiac surgery, 30-day and long-term all-cause mortality in Indigenous (Aboriginal and Torres Strait Islanders) patients in Far North Queensland (FNQ) – a region with a large Indigenous population and 24/7 cardiac catheterisation facilities.

Method

All patients who presented to the tertiary referral center for FNQ, for their first inpatient angiogram between November 2012 and October 2019 were identified. The primary study outcomes were rates of PCI or cardiac surgery and all-cause mortality measured at 30 days and long term. Secondary study outcomes were significant left ventricular dysfunction (ejection fraction <50%) and valvular disease (moderate to severe) in patients who had an echocardiogram. Other differences in baseline characteristics, including age, gender, body mass index, postcode and indication for angiography were accounted for using logistic and cox regression analysis.

Results

1042 patients (mean age 53.7±11.6 years, 45.5% female, median follow-up 1092 days) self-identified as Indigenous. Indigenous women were older 54.8±11.4 vs 52.8±11.7 years, p=0.005 and had different angiography indications. For Indigenous women and men respectively, rates of ST elevation myocardial infarction (STEMI) were 14.6% vs 22.9%, non-STEMI 44.3% vs 46.8%, angina 32.7% vs 21.0%, cardiac arrest 2.7% vs 3.3% and other 5.7% vs 6.0%, p<0.001.

Indigenous women had significantly lower rates of PCI or cardiac surgery, 40.5% vs 60.7%, p<0.001, but similar 30-day mortality, 1.5% vs 2.3% p=0.34 and long-term all-cause mortality rates 11.2% vs 10.9%, p=0.89, in unadjusted data.

685 patients (mean age 53.8±11.5 years, 45.5% female) were included in the echocardiogram subgroup. Indigenous women had significantly more valvular disease, 23.3% vs 16.3%, p=0.022 but similar rates of left ventricular dysfunction, 30.2% vs 35.8%, p=0.12.

Following adjustment for other baseline characteristics female gender independently predicted lower rates of PCI or cardiac surgery, OR 0.49 (95% CI 0.38–0.64) and higher rates of valvular disease, OR 1.60 (95% CI 1.07–2.39). Rates of ventricular dysfunction, 30-day and long-term all-cause mortality were similar.

Conclusions

Indigenous women had significantly different indications for angiography, lower rates of PCI or cardiac surgery and higher rates of clinically significant valvular disease despite presenting in gender ratios similar to the general population in FNQ.

Funding Acknowledgement

Type of funding source: None

Differences in rates of percutaneous coronary intervention, cardiac surgery and all-cause mortality in indigenous and non-indigenous Australians with suspected acute coronary events

Background

Indigenous populations globally are known to have lower revascularisation rates following acute coronary events and higher mortality partly due to inequitable access to specialised care like cardiac catheterisation. Whether these disparities persist when access is readily available is unclear.

Purpose

We compared the rates of percutaneous coronary intervention (PCI), cardiac surgery, 30-day and long-term all-cause mortality in Indigenous (Aboriginal and Torres Strait Islanders) and non-Indigenous Australians in Far North Queensland (FNQ) – a region with a large Indigenous population and 24/7 cardiac catheterisation facilities.

Method

All public patients in FNQ having their first inpatient angiogram from November 2012 to October 2019 were identified. The primary study outcomes were rates of PCI or cardiac surgery and all-cause mortality at 30 days and long term. Secondary study outcomes were significant left ventricular dysfunction (ejection fraction <50%) and valvular disease (moderate to severe) in the echocardiogram subset. Other differences in baseline characteristics, including age, gender, body mass index, postcode and indication for angiography were accounted for using logistic and cox regression analysis.

Results

We identified 4489 patients (mean age, 61.7±13.0 years, 64.9% male, median follow-up 1045 days). 1042 (23.2%) self-identified as Indigenous. Indigenous patients were younger (53.7±11.6 vs 64.1±12.5 years, p<0.001), more likely female (45.5% vs 32.0%, p<0.001) and had small differences in angiography indications, ST elevation myocardial infarction (STEMI) 19.1% vs 18.1%, non-STEMI 45.7% vs 41.8%, angina 26.3% vs 28.0%, cardiac arrest 3.1% vs 3.7% and other 5.8% vs 8.4%, p=0.02.

Rates of PCI or surgery 35.6% vs 38.5%, p=0.17, 30-day mortality 1.9% vs 2.7%, p=0.17 and long-term mortality 11.0% vs 11.5%, p=0.71 were similar in unadjusted data.

2959 patients (mean age, 62.1±13.0 years, 23.1% Indigenous, 64.9% male) were included in the echocardiogram subgroup. In unadjusted data Indigenous patients had similar rates of ventricular dysfunction 33.3% vs 31.3%, p=0.33 and valvular disease 19.4% vs 19.3%, p=0.93.

After adjustment for other baseline characteristics, Indigenous patients had higher rates of PCI or cardiac surgery, OR 1.39 (95% CI, 1.18–1.64, p<0.001), ventricular dysfunction, OR 1.31 (95% CI, 1.07–1.60), p=0.01 and valvular disease, OR 1.93 (95% CI, 1.50–2.48), p<0.001. 30-day mortality was similar but Indigenous patients had higher adjusted long-term hazard of mortality, HR 1.80 (95% CI, 1.42–2.27), p<0.001.

Conclusion

When cardiac catheterisation was readily available Indigenous patients had higher rates of PCI and cardiac surgery and similar 30-day mortality to non-Indigenous patients. Equitable access to healthcare improves outcomes but the nearly double long-term mortality of Indigenous patients shows more is required to help close the gap for disadvantaged populations.

Funding Acknowledgement

Type of funding source: None