Ethnic Differences in Coronary Artery Revascularisation in New Zealand: Does the Inverse Care Law Still Apply?

Background In 2002 striking differences in cardiac revascularisation rates were reported between New Zealand Māori, Pacific and European ethnicities. This paper examines whether this inequity still exists, taking into account ethnic differences in need. Methods Age-standardised time trends in intervention rates for coronary artery bypass grafts (CABG), percutaneous coronary intervention (PCI) and ST elevation myocardial infarction (STEMI) were calculated by ethnicity. Ethnic-specific trends were also calculated in the ratio of observed to expected CABG and PCI interventions based on the rate of hospitalisation with a diagnosis of STEMI. Results On a per capita basis, standardised CABG intervention rates were significantly higher for Pacific (both sexes) and female Māori than Other throughout 2000-2012, and were significantly higher for Māori males than Other in 2009-12. Population based PCI rates were significantly lower for male Māori from 2000-2012, while for female Māori they were significantly lower in 2000-2004 but significantly higher in 2009-12. However, and despite some improvement since 2000-2004, Māori and Pacific intervention numbers for PCI in 2009-2012 were still 22%-32% lower than expected for the rate of STEMI hospitalisation they experience. Overall revascularisation ratios were significantly lower than expected for Māori (both sexes) and Pacific females. Conclusions Large increases in the PCI population intervention rates in Māori and Pacific over the period 2000-2012 have not been sufficient to eliminate inequalities in relation to need, except perhaps for Pacific men.