Introduction:
Left ventricular hypertrophy (LVH) is more prevalent in blacks than whites, and is a major independent predictor of coronary heart disease (CHD)/CVD survival in blacks. We evaluated the ability of LVH to predict CHD outcomes beyond traditional cardiovascular risk factors in blacks, compared with whites from a large community-based cohort.
Methods:
Data were analyzed on 14,489 participants (mean age 54 +/- 5.7 years, 43.5% men, and 26% black) within the ARIC cohort, with baseline (1987-1989) electrocardiograms (ECG), followed through 2009. Risk estimates for incident CHD were assessed using the 10-year Framingham Risk Score (FRS). Model 1 was the Framingham base model, while model 2 included the base model plus LVH by any of 11 traditional ECG-LVH criteria (Table). Net reclassification improvement (NRI) was calculated, and the distribution of risk was compared using model 2 vs. model 1.
Results:
There were 690 (4.8%) 10-year and 1515 (10.5%) 20-year CHD events. LVH defined by any criteria was associated with CHD events in the entire cohort [HR (95% CI): 1.42 (1.20-1.7)]. LVH defined by the Framingham ECG score and LV strain criteria were the criteria most associated with CHD overall. LVH by Framingham ECG score was most associated with CHD in blacks [HR (95%CI): 2.53 (1.65-3.89)], while LV strain showed the strongest association with CHD in whites [1.73 (1.18-2.56)]. No statistically significant improvement in NRI or C-statistic was observed in model 2 [C-statistic (95% CI): 0.779 (0.763-0.794), NRI = 0.006 (p = 0.41)], compared with the base model [0.777 (0.762-0.792)]; and no racial interactions were observed. Findings were unchanged when the base model was replaced with the 10 and 20-year ARIC risk model (includes diabetes) for CHD.
Conclusions:
In this cohort of black and white men and women, LVH (defined by ECG) was significantly associated with CHD after adjustment for FRS; but did not significantly improve CHD risk prediction beyond the FRS. No significant black-white differences in risk prediction were observed.
Table. Reclassification of Coronary Heart Disease by the addition of each Criterion for Left Ventricular Hypertrophy, based on a 10-year Framingham Risk Model
* Base model factors in age, gender, current smoking, diabetes, systolic blood pressure, diastolic blood pressure, HDL cholesterol and total cholesterol as separate variables.
* NRI categorized as <10%, 10-20% and >20%.
Abbreviations:
NRI = Net Reclassification Index, IDI = Integrated Discrimination Index, HR = Hazard Ratio, CI = Confidence Interval
Acute blood pressure reduction causes left ventricular functional impairment in hypertensive patients with coronary heart disease and left ventricular hypertrophy
