Clinical Outcomes of Māori and Pacific Implantable Cardioverter Defibrillator Recipients in Aotearoa New Zealand (ANZACS-QI 87)

BACKGROUND This study aims to compare the clinical characteristics and outcomes of Māori and Pacific people receiving implantable cardioverter defibrillators (ICD) compared with other ethnicities. METHOD All patients who received an ICD in Aotearoa New Zealand between 2016 to 2020 were identified from a national registry for cardiac implantable electronic devices. Patients with infiltrative cardiomyopathies, congenital heart disease and channelopathies were excluded. The primary outcome was all-cause mortality. Secondary outcomes were cardiovascular disease (CVD) mortality, non-CVD mortality, heart failure (HF) hospitalisation and ventricular arrhythmia (VA) hospitalisation. Log-rank tests on Kaplan-Meier (KM) curves and 4-year KM event rates were reported. Multivariable Cox regression models were performed to determine the hazard ratio (HR) of all-cause mortality in ethnic subgroups groups compared to European/other. RESULTS There were 1,990 patients with a mean follow-up of 4.0±1.5 years. Compared to other ethnicities, Māori and Pacific patients were younger (Māori: 59 years, Pacific: 56 years, Asian: 60 years, European/other: 65 years; p<0.001), more likely to live in socioeconomically deprived areas, had more comorbidities, history of HF, New York Heart Association class III-IV, left ventricular ejection fraction ≤35% and chronic renal impairment. At 4 years, Māori and Pacific patients had higher all-cause mortality (Māori: 23.1%, Pacific: 18.6%, Asian: 5.3%, European/other: 12.0%; p<0.0001); CVD mortality (Māori: 17.4%, Pacific: 10.9%, Asian: 4.3%, European/other: 7.6%; p<0.0001), non-CVD mortality (Māori: 6.9%, Pacific: 8.7%, Asian: 1.1%, European/other: 4.8%; p=0.02), HF hospitalisation (Māori: 34.9%, Pacific: 30.9%, Asian: 19.5%, European/other: 20.8%; p<0.0001) and VA hospitalisation (Māori: 23.8%, Pacific: 29.5%, Asian: 11.0%, European/other: 20.3%; p=0.02) compared to other ethnicities. After adjustment for demographics, comorbidities, New York Heart Association class and left ventricular ejection fraction, the all-cause mortality in Māori remained elevated (HR 1.88 [1.41-2.50]), with a trend towards increased all-cause mortality in Pacific patients (HR 1.51 [0.97-2.33]) compared with European/other. CONCLUSIONS In Aotearoa New Zealand ICD recipients, all-cause mortality and HF and VA hospitalisation was substantially higher in Māori and Pacific compared to other ethnicities. Urgent efforts are needed to improve the health and healthcare of Māori and Pacific people to achieve more equitable clinical outcomes.