Mosley JD, Gupta DK, Tan J, et al. - This study was conducted to ascertain whether a polygenic risk score improves prediction of coronary heart disease compared with a guideline-recommended clinical risk equation. Researchers conducted a retrospective cohort study of the predictive accuracy of a previously validated polygenic risk score to evaluate among 4,847 adults of white European ancestry, aged 45 through 79 years, participating in the Atherosclerosis Risk in Communities (ARIC) study and 2,390 participating in the Multi-Ethnic Study of Atherosclerosis (MESA) from 1996 through December 31, 2015, the final day of follow-up. A total of 4,847 adults from the ARIC study (mean [SD] age, 62.9 [5.6] years; 56.4% women) and 2,390 adults from the MESA cohort (mean [SD] age, 61.8 [9.6] years; 52.2% women) were included. The polygenic risk score was correlated with incident coronary heart disease events but did not significantly increase discrimination, calibration, or risk reclassification compared with conventional predictors in this analysis of 2 cohorts of US adults. The data demonstrated that a polygenic risk score may not improve risk prediction in a general, white middle-aged population.