Timing of stroke risk reassessment in atrial fibrillation patients with a CHA₂DS₂-VA score of 0 or 1: the Norwegian AFNOR study

Stroke risk in atrial fibrillation (AF) patients increases over time, but the optimal reassessment interval remains unclear. This study evaluated changes in the CHA₂DS₂-VA score in AF patients with low (score 0) or intermediate (score 1) stroke risk and explored appropriate reassessment intervals.

Using Norwegian national registries (2011–18), 40 782 individuals with incident AF aged ≥18 years and a low or intermediate CHA₂DS₂-VA score were identified. Patients were followed from first AF diagnosis until an increase in the CHA₂DS₂-VA score, and the proportion with increased score was assessed across age groups. The number needed to reassess to detect one new CHA₂DS₂-VA risk factor was calculated at different time intervals after AF diagnosis. The CHA₂DS₂-VA score increased in 50% of patients after a median follow-up of 1.7 years. The proportion of patients with an increased CHA₂DS₂-VA score was 19% at 6 months, 25% at 1 year, and 40% at 3 years after AF diagnosis. At 1 year, the proportion of patients with a new risk factor was lower in those aged 18–44 years (8%) and 45–54 years (14%) compared to those aged >55 years (30%), with the number needed to reassess at 1 year being 12, 7, and 3 patients, respectively.

New risk factors emerged in half of AF patients within 1.7 years. Age-specific differences underscore the need for tailored reassessment, suggesting a shorter interval of 6 months for patients ≥55 years and 1 year for those <55 years and routinely at age 65 and 75 years.