Disparities in Revascularization Rates After Acute Myocardial Infarction Between Aboriginal and Non-Aboriginal People in Australia

Abstract

Background— This study examined revascularization rates after acute myocardial infarction (AMI) for Aboriginal and non-Aboriginal patients sequentially controlling for admitting hospital and risk factors. Methods and Results— Hospital data from the state of New South Wales, Australia (July 2000 through December 2008) were linked to mortality data (July 2000 through December 2009). The study sample were all people aged 25 to 84 years admitted to public hospitals with a diagnosis of AMI (n=59 282). Single level and multilevel Cox regression was used to estimate rates of revascularization within 30 days of admission. A third (32.9%) of Aboriginal AMI patients had a revascularization within 30 days compared with 39.7% non-Aboriginal patients. Aboriginal patients had a revascularization rate 37% lower than non-Aboriginal patients of the same age, sex, year of admission, and AMI type (adjusted hazard ratio, 0.63; 95% confidence interval, 0.57–0.70). Within the same hospital, however, Aboriginal patients had a revascularization rate 18% lower (adjusted hazard ratio, 0.82; 95% confidence interval, 0.74–0.91). Accounting for comorbidities, substance use and private health insurance further explained the disparity (adjusted hazard ratio, 0.96; 95% confidence interval, 0.87–1.07). Hospitals varied markedly in procedure rates, and this variation was associated with hospital size, remoteness, and catheterization laboratory facilities. Conclusions— Aboriginal Australians were less likely to have revascularization procedures after AMI than non-Aboriginal Australians, and this was largely explained by lower revascularization rates at the hospital of first admission for all patients admitted to smaller regional and rural hospitals, a higher comorbidity burden for Aboriginal people, and to a lesser extent a lower rate of private health insurance among Aboriginal patients.

Transfers to metropolitan hospitals and coronary angiography for rural Aboriginal and non‐Aboriginal patients with acute ischaemic heart disease in Western Australia

“…The proportion of patients who received coronary angiography in our study was higher than that recently reported by Randall et al [10] for both Aboriginal (65.5% v 48.5%) and non-Aboriginal people (69.5% v 54.3%). These differences likely stem from our case selection since we used MI as the principal diagnosis only whereas Randall used MI in principal diagnosis or in second and third diagnoses along with IHD as the principal diagnosis.…”

“…Rural WA experienced 5,540 acute IHD events (average 3 events/day) in 2005–09 with Aboriginal people over-represented and their profile being consistent with previous Australian studies [9,10,12]. Our analyses investigated patients with a principal discharge diagnosis of IHD (which encompasses acute coronary syndrome (ACS) patients) as well as those with a principal discharge diagnosis of MI to increase our specificity.…”

“…The findings on Aboriginal disparity in receiving coronary artery revascularisation procedures (CARP) are inconclusive with one study showing disparity in their fully adjusted model [9], whilst another showing disparity only in the model adjusted for demographics and admission hospital [10] and yet others showing no disparity in their fully adjusted models [11,12]. However, these analyses considered metropolitan and rural patients together.…”

Long-term Outcomes of Patients with Acute Myocardial Infarction Presenting to Regional and Remote Hospitals

“…Overall rates of revascularisation reported in the US are also much higher than our data which is likely a result of differing health systems and health practices [23]. Australian data has reported adjusted hazard ratios of 0.51-0.70 for the receipt of revascularisation in inner regional, outer regional and remote/very remote hospitals, suggesting a lesser impact of regional and remote setting than found in our data [13]. This is likely because this study reported 30-day revascularisation rates while we report revascularisation rates during the index admission.…”

“…The vast landmass and low population density of Australia is likely to be the setting most susceptible to any impact of remoteness upon health service access and patient outcomes. Recent Australian studies, focussing upon the impact of Indigenous race upon AMI treatment, have shown lower revascularisation rates and higher mortality in non-urban hospitals [13][14][15]. Other Australian registry analyses have also shown lower revascularisation rates in patients in regional and remote locations but have not been of a scale to compare the effect of location of presentation on health service utilisation and survival post AMI [16][17][18].…”