LAUSR

Purpose: We have first reported that the new progression of carotid artery plaque (Prog-PQ) is a risk factor for incident cardiovascular disease (CVD), but the Prog-PQ risk score has not been established. Methods: We studied 4,724 Japanese (mean age 59.7 years) without CVD, whose intima-media thickness (IMT) was measured with carotid ultrasonography on both sides of the entire carotid artery areas as a baseline survey (April 1994 to August 2001). We defined carotid plaque as a maximum IMT of the common carotid artery >1.1mm. We excluded subjects with carotid plaque at baseline (n=1,044), lost to follow-up (n=167), and missing data (n=2). For 3,511 subjects, carotid ultrasonographic follow-ups were performed every two years until March 2016. Blood pressures (BPs) were used the average of two measurements recorded more than 1 min apart. Cox proportional hazard ratios were analyzed after adjusting for cardiovascular risk factors. We used the area under the receiver operating characteristic curve to evaluate the model's discrimination. Results: During 38,454 person-years of follow-up, 1,771 instances of the Prog-PQ occurred. Compared to subjects with systolic BP (SBP) <120 mmHg, the adjusted hazard ratios (95% confidence intervals, CI) of the Prog-PQ were 1.18 (1.04-1.33), 1.35 (1.11-1.63), and 1.65 (1.23-2.23) in subjects with SBP=120-139 mmHg, 140-159 mmHg, and ≥160 mmHg, respectively. We developed a scoring system for each risk factor as follows: 0, 2, 4, 6, 9, and 11 points for age 30's to 80's, respectively; -1 point for women; 0, 1, and 2 points for SBP<120, 120-159, and ≥160mmHg, respectively; 0, 1, 2, and 3 points for total cholesterol<160, 160-239, 240-279, and ≥280mg/dL, respectively; 2, 0, and -1 points for HDL cholesterol<35, 35-59, and ≥60mg/dL, respectively; 1 point for overweight or current smoking; and 2 points for diabetes (C-statistic 0.647; 95% CI, 0.629-0.665). Individuals with 2 or 10 points had 27% or 62% observed probability of the Prog-PQ in 10 years, respectively. Conclusion: High SBP was a significant risk factor for the Prog-PQ. We have developed a 10-year risk score for the Prog-PQ, which can efficiently predict atherosclerosis in routine clinic/health examinations without carotid ultrasonography.