Identification, risk assessment, and management of patients with atrial fibrillation in a large primary care cohort.

BACKGROUND: Atrial fibrillation (AF) is associated with increased risk of cardiovascular disease (CVD) complications including stroke. We investigated the assessment and management of cardiovascular risk among patients with AF aged 35-74years, by ethnic group, in a large cohort of people receiving a CVD risk assessment in primary care (PREDICT).

METHODS: PREDICT was linked to national dispensing, hospitalisation and mortality records. AF was present if recorded in PREDICT or during a prior hospitalisation; medications were those dispensed ≤6months before or after a PREDICT assessment; the CHA2 DS2 -VASc score and a New Zealand (NZ) adjusted Framingham CVD risk were calculated. Data were linked to outcomes of stroke or major adverse cardiovascular event (MACE).

RESULTS: 12,739 (2.8%) of 447,020 people aged 35-74years had AF. Māori, the indigenous population of NZ, had the highest proportion of AF, which by age group, was similar to that among Europeans 10years older. 77% were at high stroke risk, of whom 42% received anticoagulation; 54% were at high CVD risk, of whom 67% received both lipid- and blood pressure-lowering medication. Per category of predicted risk, stroke risk was overestimated and risk of MACE was underestimated.

CONCLUSIONS: The burden of AF and risk factors differed by ethnic group thus recommendations to screen for AF above a universal age threshold may introduce inequity in the detection and management of associated risk. The high burden of comorbidities at younger ages among many ethnic groups contributes to the poor performance of available risk assessment tools, further compounding potential inequity.