Burden of atrial fibrillation in Māori and Pacific people in New Zealand: a cohort study

Background: Atrial fibrillation (AF) is a major risk factor for ischaemic stroke and cardiovascular events. In New Zealand (NZ), Māori (indigenous New Zealanders) and Pacific people experience higher rates of AF compared with non-Māori/non-Pacific people.

Aim: To describe a primary care population with AF in NZ. Stroke risk and medication adherence according to ethnicity are also detailed.

Methods: Electronic medical records for adults (≥20 years, n = 135 840, including 19 918 Māori and 43 634 Pacific people) enrolled at 37 NZ general practices were analysed for AF diagnosis and associated medication prescription information.

Results: The overall prevalence of non-valvular AF (NVAF) in this population was 1.3% (1769), and increased with age (4.4% in people ≥55 years). Māori aged ≥55 years were more likely to be diagnosed with NVAF (7.3%) than Pacific (4.0%) and non-Māori/non-Pacific people (4.1%, P < 0.001). Māori and Pacific NVAF patients were diagnosed with AF 10 years earlier than non-Māori/non-Pacific patients (median age of diagnosis: Māori = 60 years, Pacific = 61 years, non-Māori/non-Pacific = 71 years, P < 0.001). Overall, 67% of NVAF patients were at high risk for stroke (CHA₂ DS₂ -VASc ≥ 2) at the time of AF diagnosis. Almost half (48%) of Māori and Pacific NVAF patients aged <65 years were at high risk for stroke, compared with 22% of non-Māori/non-Pacific (P < 0.001). Irrespective of ethnic group, adherence to AF medication was suboptimal in those NVAF patients with a high risk of stroke or with stroke history.

Conclusion: AF screening and stroke thromboprophylaxis in Māori and Pacific people could start below the age of 65 years in NZ.