Cardiovascular Disease Risk Prediction Factors

To the Editor: The recent ERFC meta-analysis¹ indicated that the standard hazard ratio (HR) for cardiovascular disease using baseline levels of non-HDL-C was 1.27 (95% CI, 1.22 to 1.33) vs 1.24 (1.19 to 1.29) using apolipoprotein B. In a head-to-head comparison, the HR for apolipoprotein B relative to the HR for non-HDL-C was lower: −2.4% (95% CI, −4.1% to −0.6%), assuming a correlation (r = 0.91) between the 2 markers.² This contrasts with the within-study comparisons in our meta-analysis,² which found the standard HR for coronary heart disease of apolipoprotein B averaged 5.7% (95% CI, 2.4% to 9.1%) higher than that of non-HDL-C. Our meta-analysis focused on HRs rather than the C statistic or the Cohen d statistic to aid assessment of the relative utility of each marker to target treatment rather than to just assess risk. Thus each meta-analysis estimated statistically significant associations in opposite directions with different but related outcomes. We wonder how there could be such a systematic difference in findings.