Left ventricular hypertrophy and cardiovascular disease risk prediction and reclassification in blacks and whites: the Atherosclerosis Risk in Communities Study.

BACKGROUND: Left ventricular hypertrophy (LVH) is a major independent predictor of cardiovascular disease (CVD) survival and is more prevalent in blacks than whites. In a large biracial population, we evaluated the ability of electrocardiography (ECG)-determined LVH (ECG-LVH) to reclassify CVD/coronary heart disease (CHD) events beyond traditional risk factors in blacks and whites. METHODS: The analysis included 14,489 participants (mean age 54 ± 5.7 years; 43.5% men; 26% black) from the ARIC cohort, with baseline (1987-1989) ECG, followed up for 10 years. Predicted risk for incident CVD and CHD were estimated using the 10-year Pooled Cohort and Framingham risk equations (base models 1A/1B), respectively. Models 2A and 2B included respective base model plus LVH by "any" of 10 traditional ECG-LVH criteria. Net reclassification improvement (NRI) was calculated, and the distribution of risk was compared using models 2A and 2B versus models 1A and 1B, respectively. RESULTS: There were 792 (5.5%) 10-year Pooled Cohort CVD events and 690 (4.8%) 10-year Framingham CHD events. Left ventricular hypertrophy defined by any criteria was associated with CVD and CHD events (hazard ratio [95% CI] 1.62 [1.38-1.90] and 1.56 [1.32-1.86], respectively]. Left ventricular hypertrophy did not significantly reclassify or improve C statistic in models 2A/B (C statistics 0.767/0.719; NRI = 0.001 [P = not significant]), compared with the base models 1A/B (C statistics 0.770/0.718), respectively. No racial interactions were observed. CONCLUSIONS: In this large cohort of black and white participants, ECG-LVH was associated with CVD/CHD risk but did not significantly improve CVD and CHD events risk prediction beyond the new Pooled Cohort and most used Framingham risk equations in blacks or whites.