Between 1999 and 2006, the prevalence of U.S. adults with high levels of LDL cholesterol decreased by about one-third, according to a study in the Nov. 18 issue of the Journal of the American Medical Association. However, a high percentage of adults still are not being screened or treated for high cholesterol levels.
Elevated levels of LDL-C are a primary focus for cholesterol management of the National Cholesterol Education Program Adult Treatment Panel (ATP) III. “The guidelines set LDL-C target levels that are based on the history of coronary heart disease (CHD) or risk for developing CHD in the next 10 years,” the authors wrote. They also noted that few studies have described the prevalence of high LDL-C levels and the use of lipid-lowering medications across all CHD risk categories.
Elena V. Kuklina, MD, PhD, of the Centers for Disease Control and Prevention in Atlanta, and colleagues investigated trends in the prevalence of screening, current use of cholesterol-lowering medication, and high LDL-C levels across four study cycles (1999-2000, 2001-2002, 2003-2004 and 2005-2006).
The researchers used data from the National Health and Nutrition Examination Survey (NHANES), and restricted the study sample to fasting participants age 20 years or older (8,018), excluded pregnant women (464) and participants with missing data (510), with the final study sample consisting of 7,044 participants.
The overall prevalence for high LDL-C levels decreased from 31.5 percent in 1999-2000 to 21.2 percent in 2005-2006, according to the investigators.
“However, this prevalence varied substantially by risk category. The highest prevalence of high LDL-C levels was observed in the high-risk ATP III category with 69.4 percent and 58.9 percent during the first and last cycles, respectively,” the authors wrote.
Participants with a self-reported history of CHD, angina, heart attack, stroke and diabetes mellitus or participants with a fasting blood glucose level of 126 mg/dL or greater were placed in the high ATP III risk category.
Kuklina and colleagues did not observe any significant changes in the weighted age-standardized screening rates from 1999-2000 to 2005-2006. Among participants with high LDL-C levels, 35.5 percent were unscreened, 24.9 percent undiagnosed and 39.6 percent untreated or inadequately treated in 2005-2006.
In the high-risk category, about one-fifth of participants were eligible for lipid-lowering drug therapy but were not receiving it in 2005-2006.
“Self-reported use of lipid-lowering medications increased from 8 percent to 13.4 percent, but screening rates did not change significantly, remaining less than 70 percent during the study periods,” the authors wrote. They add that the goal of improving screening rates may be hindered by the lack of consensus regarding the age at which screening should start.
In an accompanying editorial, J. Michael Gaziano, MD, of the VA Boston Healthcare System and Brigham and Women’s Hospital in Boston, and Thomas A. Gaziano, MD, of Brigham and Harvard School of Public Health in Boston, suggested that the cholesterol guidelines need to be simplified.
“Even though there has been progress in identifying and treating patients with dyslipidemia, the current guidelines are overly complicated, and a simplified risk-based approach is supported by the current data,” they wrote.
“Abandoning the fixed LDL-C threshold and targets used in many guidelines is justified by the linear relationship of cholesterol lowering and the benefit of the intervention for preventing cardiovascular disease,” the editorialists suggested. “The use of a simplified risk-based approach could increase the ease of implementation of treatment and increase the number of patients receiving beneficial lipid-lowering therapy.”