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Prevalence of Cholesterol Treatment Eligibility and Medication Use Among Adults — United States, 2005–2012

MMWR Weekly Vol. 64, No. 47 December 4, 2015

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Prevalence of Cholesterol Treatment Eligibility and Medication Use Among Adults — United States, 2005–2012

Weekly

December 4, 2015 / 64(47);1305-11

Carla Mercado, PhD1; Ariadne K. DeSimone2,3; Erika Odom, PhD1; Cathleen Gillespie, MS1; Carma Ayala, PhD1; Fleetwood Loustalot, PhD1

A high blood level of low-density lipoprotein cholesterol (LDL-C) remains a major risk factor for atherosclerotic cardiovascular disease (ASCVD) (1), although data from 2005 through 2012 has shown a decline in high cholesterol (total and LDL cholesterol) along with an increase in the use of cholesterol-lowering medications (2–4). The most recent national guidelines (published in 2013) from the American College of Cardiology and the American Heart Association (ACC/AHA) expand previous recommendations for reducing cholesterol to include lifestyle modifications and medication use as part of complete cholesterol management and to lower risk for ASCVD (5–8). Because changes in cholesterol treatment guidelines might magnify existing disparities in care and medication use, it is important to describe persons currently eligible for treatment and medication use, particularly as more providers implement the 2013 ACC/AHA guidelines. To understand baseline estimates of U.S. adults on or eligible for cholesterol treatment, as well as to identify sex and racial/ethnic disparities, CDC analyzed data from the 2005–2012 National Health and Nutrition Examination Surveys (NHANES). Because the 2013 ACC/AHA guidelines focus on initiation or continuation of cholesterol treatment, adults meeting the guidelines' eligibility criteria as well as adults who were currently taking cholesterol-lowering medication were assessed as a group. Overall, 36.7% of U.S. adults or 78.1 million persons aged ≥21 years were on or eligible for cholesterol treatment. Within this group, 55.5% were currently taking cholesterol-lowering medication, and 46.6% reported making lifestyle modifications, such as exercising, dietary changes, or controlling their weight, to lower cholesterol; 37.1% reported making lifestyle modifications and taking medication, and 35.5% reported doing neither. Among adults on or eligible for cholesterol-lowering medication, the proportion taking cholesterol-lowering medication was higher for women than men and for non-Hispanic whites (whites) than Mexican-Americans and non-Hispanic blacks (blacks). Further efforts by clinicians and public health practitioners are needed to implement complementary and targeted patient education and disease management programs to reduce sex and racial/ethnic disparities among adults eligible for treatment of cholesterol.

NHANES is an ongoing national survey using a complex, multistage, probability sampling design to measure the health and nutritional status of the noninstitutionalized U.S. population.* Detailed physical examinations, including laboratory measures and interviews, were conducted. Data from four 2-year cycles (2005–2012) were analyzed. Exam response rates ranged from 70% to 77% for 22,281 participants aged ≥21 years. Participants were excluded from the analyses if they were pregnant (n = 491) or missing a fasting laboratory specimen (n = 13,155), or if treatment eligibility could not be determined (n = 273). When using survey analyses to address the complex sampling design, fasting sample weights were used to account for missing fasting laboratory measures. The final study sample included 8,644 participants. Serum LDL-C levels were calculated based on the Friedewald method (9) using the measured values of total cholesterol, triglycerides, and high-density lipoprotein cholesterol (HDL-C). Adults who were currently taking any cholesterol-lowering medication, or who met eligibility criteria for medication based on the 2013 ACC/AHA guidelines, were defined as meeting current eligibility guidelines for cholesterol treatment.

Current cholesterol-lowering medication use was self-reported from the medical history interview or transcribed from medication bottles recorded in the prescription medication interview.† As outlined by the 2013 ACC/AHA guidelines, persons who should initiate or continue cholesterol-lowering medication included four groups: 1) persons with clinical ASCVD (self-reported history of coronary heart disease, myocardial infarction, stable or unstable angina, or stroke); 2) persons with LDL-C ≥190 mg/dL; 3) persons aged 40–75 years with diabetes, LDL-C 70–189 mg/dL, and without clinical ASCVD; and 4) persons aged 40–75 years without clinical ASCVD or diabetes, with LDL-C 70–189 mg/dL, and estimated 10-year ASCVD risk from Pooled Cohort Equation§ ≥7.5% (5,6). Lifestyle modifications were based on affirmative responses when asked whether a "doctor or health professional ever told you to (increase exercise, eat fewer high fat or high cholesterol foods, or control weight to) lower your cholesterol" and self-report that the participant is "now following this advice." Because lifestyle modification questions were not asked for NHANES cycle 2011–2012, estimates for all lifestyle modifications apply to NHANES cycles 2005–2010. All other estimates apply to NHANES cycles 2005–2012.

Analyses were performed using fasting sample weights and adjusted variance estimates to account for complex sampling. Pearson's chi-square test was used to determine significant differences (p<0.05) across sex and racial/ethnic groups. Population counts were estimated using population totals provided from NHANES and averaging the population during the time coinciding with the four NHANES cycles.¶

Overall, 36.7% of U.S. adults or 78.1 million persons aged ≥21 years were on or eligible for cholesterol treatment, among whom 55.5% were taking cholesterol-lowering medication, and 46.6% reported making lifestyle modifications to lower cholesterol. There were significant differences in the percentage of men (40.8%) and women (32.9%; p≤0.001) on or eligible for treatment as well as among racial/ethnic groups (24.2% for Mexican-Americans, 38.4% for whites, and 39.5% for blacks; p<0.001) (Table 1). Among persons on or eligible for treatment, there were significant differences in the proportion taking cholesterol-lowering medication between men and women (52.9% versus 58.6%; p = 0.010) and racial/ethnic groups (58.0% for whites, 47.1% for Mexican-Americans, and 46.0% for blacks; p<0.001). Significant differences in the proportion of participants on or eligible for cholesterol-lowering medication were also found among subgroups of age, poverty-to-income ratio, body mass index (BMI), and presence of diabetes or hypertension.

Prevalence of cholesterol-lowering medication use among adults eligible for treatment varied within sex and racial/ethnic subgroups, with the lowest prevalence (5.7%) among blacks who did not have a routine place for health care and the highest prevalence among persons who reported making lifestyle modifications (approximately 80% for a majority of subgroups) (Table 2). Among adults on or eligible for treatment, prevalence of cholesterol-lowering medication use (p≤0.001) and making lifestyle modifications (p = 0.001) was higher for those with lower LDL-C levels (Figure).

Discussion

During 2005–2012, based on the 2013 ACC/AHA guidelines, approximately 37% of U.S. adults were on or eligible for cholesterol-lowering medication. Eligibility for and use of cholesterol-lowering medication differed by sex and race/ethnicity across various sociodemographic and health-related factors. Among adults who were eligible for treatment, disparities in the proportion taking cholesterol-lowering medication existed among categories of sex, racial/ethnicity, age, poverty-to-income ratio, BMI, and presence of diabetes or hypertension. This report is one of the first to examine sex and racial/ethnic differences in medication use in a nationally representative sample of adults who are eligible for treatment.

Similar to those of previous reports (7,10), these results indicate that approximately half of treatment-eligible adults were taking cholesterol-lowering medication according to the newly released 2013 ACC/AHA guidelines. Furthermore, lower percentages of treatment-eligible Mexican-Americans and blacks were taking cholesterol-lowering medication compared with whites. A majority of persons who reported making lifestyle modifications were also taking cholesterol-lowering medication. Lifestyle modifications, including engaging in regular physical activity, adhering to a heart-healthy diet, and maintaining a healthy weight, are well-known primary and critical components of health promotion and ASCVD risk reduction when implemented before and in combination with cholesterol-lowering medication (5,8). In alignment with incentives offered to health providers in the use of electronic medical records to improve patient care and to promote equitable and high-quality care, clinicians and public health practitioners can use sociodemographic data within their electronic health records to characterize the populations within their practices who are eligible for cholesterol treatment and implement targeted screening, patient education, and disease management programs. In addition, the 2013 ACC/AHA guidelines propose that clinicians monitor therapeutic response to cholesterol-lowering medications and reinforce adherence to both lifestyle regimens and medication at regular intervals (5). Finally, stakeholders should implement evidence-based interventions from the Guide to Community Preventive Services to improve screening and management of cholesterol.**

The findings in this report are subject to at least five limitations. First, the proportion of adults eligible for treatment might be underestimated, because older adults in nursing homes or other institutions, who are more likely to be eligible for cholesterol treatment, are not included in NHANES. Second, estimates for lifestyle modifications only represent data from 2005–2010. Third, although NHANES data collection is standardized, self-reported data are subject to recall bias. Fourth, adults taking cholesterol-lowering medications were considered to be receiving treatment aligned with the 2013 ACC/AHA guidelines, potentially overestimating prevalence of eligibility and treatment use. Fifth, persons taking medication included any type of cholesterol-lowering medication and not only statin therapy as recommended by the 2013 ACC/AHA guidelines. However, based solely on the prescription medication file, approximately 88% of persons taking any cholesterol-lowering medication were taking statins.

Cholesterol treatment for the reduction of ASCVD risk is promoted widely in the United States, including activities such as Healthy People 2020 (11) and the Million Hearts initiative (12). CDC-funded state programs use public health strategies for cardiovascular disease and risk factor management outlined in the Million Hearts initiative, including strategies related to improving clinical management of cholesterol. For example, CDC supports Well-Integrated Screening and Evaluation for Women Across the Nation (WISEWOMAN)†† programs in 20 states and two tribal organizations, and State Public Health Actions to Prevent and Control Diabetes, Heart Disease, Obesity, and Associated Risk Factors and Promote School Health§§ grants in all 50 states and the District of Columbia. These include and provide healthy behavior support for populations at risk and provide comprehensive and effective management of primary cardiovascular disease risk factors. Coordinated community and clinical programs are needed to better identify all persons now eligible for cholesterol treatment.

1Divison of Heart Disease and Stroke Prevention, National Center for Chronic Disease Prevention and Health Promotion, CDC; 2Emory University School of Medicine, Atlanta, Georgia; 3Rollins School of Public Health, Emory University, Atlanta, Georgia.

Corresponding author: Carla Mercado, cmercado@cdc.gov, 770-488-8075.

References

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11. US Department of Health and Human Services. Healthy people 2020: heart disease and stroke. Washington DC: US Department of Health and Human Services; 2013. Available at http://www.healthypeople.gov/2020/topics-objectives/topic/heart-disease-and-stroke.
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* Additional information available at http://www.cdc.gov/nchs/nhanes.htm.

† Cholesterol-lowering medication considered from medication bottles included bile acid sequestrants, cholesterol absorption inhibitors, HMG-CoA reductase inhibitors (statins), fibric acid derivatives, or combinations/others.

§ Race- and sex-specific equations considering age, total cholesterol, HDL-C, systolic blood pressure, hypertension medication use, smoking status, and diabetes status to calculate 10-year ASCVD risk.

¶ Additional information available at http://www.cdc.gov/nchs/nhanes/response_rates_cps.htm.

** Additional information available at http://www.thecommunityguide.org/cvd/ROPC.html.

†† Additional information available at http://www.cdc.gov/wisewoman.

§§ Additional information available at http://www.cdc.gov/dhdsp/programs/spha/index.htm.