January 13, 2015
The American Journal of Cardiology
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The authors of this study examined the relationship between lipid levels and all-cause mortality in 115,492 patients hospitalized for acute myocardial infarction (AMI) between 2002 and 2006. The risk for in-hospital mortality for patients with LDL-C levels in the second to fourth quartiles was decreased relative to levels in the lowest quartile ( The authors conclude that these results suggest a lipid paradox (lower LDL-C levels associated with increased risk for in-hospital mortality), which is contrary to results reported in other settings. Research should focus on further exploration of the association between very low levels of LDL-C, myocardial necrosis, and adverse cardiovascular events.
Abstract
Lipoprotein levels are currently recognized as independent risk factors for long-term cardiovascular events after acute myocardial infarction (AMI). During the acute-phase reaction following AMI, previous studies have reported trends of decreased low-density lipoprotein cholesterol (LDL-C), increased triglycerides, and variable high-density lipoprotein cholesterol (HDL-C) levels, often proportional to the severity of myocardial necrosis. However, the association between LDL-C and HDL-C levels and in-hospital mortality has not been well established following AMI. The relationship between lipid levels and in-hospital all-cause mortality in 115,492 patients hospitalized for AMI (July 2002–December 2006), registered in the National Registry of Myocardial Infarction (NRMI) 4b–5, was evaluated using multivariable-adjusted logistic regression models. Mean LDL-C was 104 ± 38, HDL-C 41 ± 14 and triglycerides 143 ± 83 (mg/dl). Compared with the lowest quartile of LDL-C (< 77 mg/dl), the risk of in-hospital mortality in the 2nd– 4th quartiles was decreased (adjusted odds ratio [OR] = 0.79, 0.80 and 0.85, respectively). For HDL-C, only those in the lowest quartile (< 31 mg/dl) had higher risk of in-hospital mortality (OR = 1.20) compared with the highest quartile (≥ 47 mg/dl). Results from NRMI 4b−5 suggest a lipid paradox, with lower LDL-C levels associated with increased risk of in-hospital mortality, contrary to findings outside of the acute setting. Consistent with previous analyses, lowest HDL-C levels were associated with increased in-hospital mortality. In conclusion, further explorations of the relationship between very low levels of LDL-C, myocardial necrosis and subsequent adverse cardiovascular events are warranted.