Data released today at the American Heart Association (AHA) Scientific Sessions 2009 define the increased risk of heart attacks and cardiovascular disease in patients with low levels of HDL-C (known as "good cholesterol"). The data also determine that statins are unable to significantly impact the heart attack or cardiovascular disease risks associated with low HDL-C.
"We believe most clinicians will be surprised to see the magnitude of the effect of low HDL-C on heart attack risk and how little statins impact the risk associated with low HDL-C," said Richard Karas, M.D., Ph.D., Professor of Medicine, Tufts University School of Medicine and Associate Director, Molecular Cardiology Research Institute, Tufts Medical Center, who led this study.
"While statins overall prevent 4 heart attacks per 1,000 patient-years, these new findings demonstrate that a 10 point higher HDL-C level could save an additional 8 heart attacks per 1,000 patient-years, which indicates that, even if patients are on a statin, if they have low HDL-C, they may need more than just statins to significantly reduce their risks," added Karas. Furthermore, this reduction of 8 heart attacks per 1000 patient-years for every 10 mg/dl change in HDL-C is the same whether patients are or are not treated with a statin.
The study led by Karas, titled "Statin Therapy Does Not Reduce the Increased Cardiovascular Risk Associated with Low Levels of High-Density Lipoprotein Cholesterol: Evidence from Randomized Controlled Trials", show that every 10 point decrease (10 mg/dL reduction) in HDL-C was associated with 7.8 more heart attacks per 1,000 person-years in the non-statin group (95% CI 2.8-13.0) and 7.6 more heart attacks per 1,000 person-years in statin-treated patients (95% CI 3.9-11.3) (P = 0.45 for comparing the effect of HDL-C on MI risk in controls versus statin-treated patients).
In addition to heart attack risk, the study also explored the association of HDL-C and cardiovascular disease (CVD) as a secondary analysis, as well as the outcomes of coronary heart disease death, CVD death, and all-cause death. In all cases, findings indicated that the risks increased as the levels of HDL-C decreased, and there were minimal differences between the groups with and without the statin. These findings also support that the low levels of HDL-C may contribute importantly to the unacceptably high residual risk of CVD events even in statin-treated patients.
The study also found that, overall, statin treatment reduced heart attacks by a median of 4.4 incidents per 1,000 person-years, indicating its significant impact on LDL-C (known as "bad cholesterol").
"With the ongoing cholesterol debates among lipidologists and cardiologists, these outcomes, coupled with the ARBITER6 data, will be extremely valuable for physicians treating patients with low levels of HDL today," continued Karas.
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