Development of a Basic Risk Score for Incident Atrial Fibrillation in a Japanese General Population - The Suita Study -

Background: An atrial fibrillation (AF) risk score for a non-Western general population has not been established. Methods and Results: A total of 6,898 participants (30-79 years old) initially free of AF have been prospectively followed for incident AF since 1989. AF was diagnosed when AF or atrial flutter was present on ECG at a biannual health examination; was indicated as a current illness; or was in the medical records during follow-up. Cox proportional hazard ratios were analyzed after adjusting for cardiovascular risk factors at baseline. During the 95,180 person-years of follow-up, 311 incident AF events occurred. We developed a scoring system for each risk factor as follows: 0/-5, 3/0, 7/5, and 9/9 points for men/women in their 30 s-40 s, 50 s, 60 s, and 70 s, respectively; 2 points for systolic hypertension, overweight, excessive drinking, or coronary artery disease; 1 point for current smoking; -1 point for moderate non-high-density lipoprotein-cholesterol; 4 points for arrhythmia; and 8, 6, and 2 points for subjects with cardiac murmur in their 30 s-40 s, 50 s, and 60 s, respectively (C-statistic 0.749; 95% confidence interval, 0.724-0.774). Individuals with score <= 2, 10-11, or >= 16 points had, respectively, <= 1%, 9%, and 27% observed probability of developing AF in 10 years. Conclusions: We developed a 10-year risk score for incident AF using traditional risk factors that are easily obtained in routine outpatient clinics/health examinations without ECG.