Timing of stroke risk reassessment in atrial fibrillation patients with 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 (2011-2018), 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 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.