University of Pittsburgh



ABSTRACT

Background:

In 2013, the American College of Cardiology (ACC) and the American Heart Association (AHA) published recommendations for lipid management incorporating a new risk score for assessment of 10-year atherosclerotic cardiovascular disease, abbreviated as ASCVD scores. Statins are recommended for 4 specific groups of adults under the age of 75 years: 1) with vascular disease; 2) an LDL-C ≥ 190mg/dL; 3) with Diabetes Mellitus (DM) (and aged 40 - 75); and 4) with an ASCVD score ≥ 7.5%. Data on implementation of these recommendations among minority women are scarce. The purpose of this analysis was to examine racial differences in statin eligibility and use.

Methods:

Data from the Study of Women’s Health across the Nation (SWAN), a prospective, multiethnic cohort study of women, ages 42-52 at time of enrollment, and were used for the present analysis. Participants who contributed data at Visit 12 (2009- 2011) were included. Women were grouped into the four groups defined by the ACC/AHA lipid guidelines. Analysis was performed using Analysis of Variance (AOV), Chi-Square and logistic regression adjusting for age, BMI, site of study and education of the participants.

Results:

Of the 2399 women who were included, 234 had a cardiovascular disease diagnosis, 354 had Diabetes Mellitus (DM), 53 had an LDL-C ≥ 190 mg/dL and 174 had an ASCVD risk score ≥ 7.5%. Rates of statin use among those with elevated risk was low; 49.5% of those with CVD; 61.6% of those with DM, and 13.2% of those with LDL-C ≥ 190 mg/dL. Blacks and Hispanics had the lowest rates of statin use among these three risk groups. Only 24.7% of the women with an ASCVD score of ≥ 7.5% were on a statin. Blacks were more likely to have an ASCVD risk score ≥ 7.5% than Whites (OR=5.6, confidence interval [CI] 3.5-8.8). Of statin eligible women, 18.8% of the Black women were on a statin compared to 36.4% of the White women. Though not statistically significant, Blacks were less likely to be on a statin (OR=0.57, 95% CI 0.21-1.39) compared to Whites.

Conclusion:

Among a large, multiethnic cohort of midlife women, women in the four groups recommended for statin therapy by the current AHA guidelines, have low rates of statin use. Rates of statin use were low across all race/ethnic groups. Minority women, in particular, Blacks were more likely to fall into one of the four groups recommended for statin use.

Public health significance:

One out of every six deaths in the United States is due to coronary heart disease. Eating habits and other lifestyle factors play a key role in causing heart disease. The approach for primary prevention of cardiovascular events depends on assessing the risk using various scores. Our results indicate that risk assessment using the 2013 ACC/AHA guidelines for estimating 10-year atherosclerotic cardiovascular disease risk, could lead to lower rates of cardiovascular events. Accurate identification of such people allows healthcare professionals, policymakers and others to target prevention and treatment to those at the highest risk of morbidity and mortality.

TABLE OF CONTENTS

preface viii

1.0 Introduction 1

1.1 Cardiovascular risk assessment 2

1.1.1 Framingham risk Score (FRS) 3

1.1.2 2013 ACC/AHA 10-year ASCVD score 4

1.1.3 Hypotheses 4

2.0 METHODS 6

2.1.1 Sample for analysis 7

2.1.2 Statistical analysis 9

3.0 RESULTS 10

3.1.1 Baseline Characteristics 10

3.1.2 Statin eligibility and use 13

4.0 dISCUSSION 18

5.0 Conclusion 22

BIBLIOGRAPHY 23

List of tables

Table 1. Demographics of women at Visit 12 after excluding those with CAD, CVD, DM or both 11

Table 2. The eligibility for statin use based on ASCVD score (≥ 7.5%) and Framingham risk Score (FRS) (≥ 10%) 14

Table 3. Statin use among women who are eligible under ASCVD score and FRS 14

Table 4. Statin use based on 2013 ACC/AHA guidelines (ASCVD) 16

Table 5. Statin use based on ATP III guidelines (FRS) 17

List of figures

Figure 1. Flow chart for analysis sample 8

preface

Acknowledgement:

The Study of Women's Health across the Nation has grant support from the National Institutes of Health (NIH), DHHS, through the National Institute on Aging (NIA), the National Institute of Nursing Research (NINR) and the NIH Office of Research on Women’s Health (ORWH) (Grants U01NR004061; U01AG012505, U01AG012535, U01AG012531, U01AG012539, U01AG012546, U01AG012553, U01AG012554, U01AG012495). The content of this paper is solely the responsibility of the authors and does not necessarily represent the official views of the NIA, NINR, ORWH or the NIH.

Introduction

Globally, the incidences of cardiovascular diseases are increasing at an alarming rate. Nearly 2,200 Americans die of cardiovascular diseases daily, with an average of one death occurring every 40 seconds. Studies show that hyperlipidemia is an important risk factor for cardiovascular diseases.(Goldstein, Hazzard, Schrott, Bierman, & Motulsky, 1973). LDL-C, total cholesterol and triglycerides are directly related to cardiovascular disease prevalence (Castelli et al., 1977). Therefore, primary prevention of cardiovascular events includes lipid management. Individuals’ ≥21 years of age with LDL-C (≥190 mg/dL) are placed in the highly susceptible category for developing atherosclerotic cardiovascular events during their lifetime due to genetic predisposition. For every 39 mg/dL decrease of LDL-C level using statins, the risk for cardiovascular diseases lowers by 20%. (Mahmood, Jahan, & Habibullah, 2015). A Clinical trial using Atorvastatin reported that, 10 mg daily, is safe and effective for the primary prevention of major cardiovascular events in patients with type 2 Diabetes Mellitus (DM) with LDL-C of 4.14mmol/L (74.6 mg/dL) (Colhoun et al., 2004). However, no justification is available for specifying a particular threshold level of LDL-C as the sole arbiter at which patients with type 2 diabetes should receive statins. Other studies have suggested that 6 - 12 months of treatment with statins elicits beneficial cardiovascular effects (Mansi, English, Zhang, Mortensen, & Halm, 2016).

Estimating cardiovascular risk in an asymptomatic population is a challenge.  Therefore, developing efficient methods for calculating the risk for future cardiovascular events is of paramount importance. The widely used risk assessment method until 2013 was the Framingham Risk Score (FRS) method which estimated 10 - year coronary risk. However, the FRS underestimates risk in women because for a given risk score, the 10-year risk for a woman is lower than that for a man. Consider, for example, a 55-year-old man who has a total cholesterol level of 250 mg/dL and an HDL-C level of 40 mg/dL, is a nonsmoker, has a systolic blood pressure (SBP) measurement of 160 mm Hg, and is on no medications. Using the ATP III tables, his point count is 15 equivalent to a 10-year cardiovascular risk of 20%, elevating him to a cardiovascular risk equivalent (e.g., stroke, aortic aneurysm, peripheral arterial disease, DM, metabolic syndrome). In contrast, a woman with exactly the same numbers would receive a higher point count of 18, but her 10-year cardiovascular risk would only be 6%. Although the difference is because men are at risk 10 years earlier than women, this feature of the FRS tool has received criticism. (Linton, Fazio, & National Cholesterol Education Program - the third Adult Treatment, 2003)

1 Cardiovascular risk assessment

Two cardiovascular risk assessment algorithms, namely 2013 ACC/AHA 10-year ASCVD and FRS, were used to calculate the 10-year risk of a cardiovascular event in this study. These scores were then used to identify statin eligible women in the study sample.

1 Framingham risk Score (FRS)

The FRS is a risk prediction model that has been used in the general population to forecast cardiovascular events and to tailor preventative therapy from 2008 to 2013. The FRS calculates the 10-year risk for coronary events using a combination of risk factors: chronological age, gender, total cholesterol, HDL-C, smoking history, systolic blood pressure (SBP), and presence of DM. However, other risk factors such as metabolic syndrome (abdominal obesity, atherogenic dyslipidemia, insulin resistance ± glucose intolerance, proinflammatory state, prothrombotic state) and family history are not included in the calculation.

The FRS categorizes coronary risk as low risk (0-10%), intermediate risk (10-20%) or high risk (20% and higher) for coronary events within 10 years. Additionally, intermediate risk is subdivided into moderate risk or moderately high risk. Moderate risk includes those with a low risk FRS and 2 or more risk factors. Moderately high risk involves those with intermediate FRS risk and 2 or more risk factors. The risk factors for this sub-classification are cigarette smoking, hypertension (HTN) (140/90 mmHg or on therapy), low HDL-C ( ................
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