Ethnic differences in case fatality following an acute ischaemic heart disease event in New Zealand: ANZACS-QI 13.

BACKGROUND

The aim of this study was to investigate ischaemic heart disease (IHD) case fatality in high-risk ethnic populations in New Zealand.

DESIGN

This is a national data-linkage study using anonymised hospitalisation and mortality data.

METHODS

Linked individual patient data were used to identify 35-84-year-olds who experienced IHD events (acute IHD hospitalisations and/or deaths) in 2009-2010. Subjects were classified as: (i) hospitalised with IHD and alive at 28 days post-event; (ii) hospitalised with IHD and died within 28 days; (iii) hospitalised with a non-IHD diagnosis and died from IHD within 28 days; or (iv) died from IHD but not hospitalised. Multinomial logistic regression was used to estimate the proportion of people in each group, as well as overall 28-day case fatality, adjusted for ethnic differences in demographic and comorbidity profiles.

RESULTS

A total of 26,885 people experienced IHD events (11.3% Māori, 4.0% Pacific and 2.5% Indian); 3.3% of people died within 28 days of IHD hospitalisations, 5.1% died of IHD within 28 days of non-IHD hospitalisations and 13.0% died of IHD without any recent hospitalisation. Overall adjusted case fatality was 12.6% in Indian, 20.5% in European, 26.0% in Pacific and 27.6% in Māori people. Compared to Europeans, the adjusted odds of death were approximately 50% higher in Māori and Pacific people and 50% lower in Indians, regardless of whether they were hospitalised.

CONCLUSIONS

Major ethnic inequalities in IHD case fatality occur with and without associated hospitalisations. Improvements in both primary prevention and hospital care will be required to reduce inequalities.