Coronary heart disease (CHD) is the number one cause of

CME Topic Aspirin for Primary Prevention of Coronary Heart Disease: Using the Framingham Risk Score to Improve Utilization in a Primary Care Clinic S...
Author: Paul Gaines
0 downloads 0 Views 470KB Size
CME Topic

Aspirin for Primary Prevention of Coronary Heart Disease: Using the Framingham Risk Score to Improve Utilization in a Primary Care Clinic Steven C. Romero,

MD,

Kristina M. Dela Rosa,

Objectives: Coronary heart disease (CHD) is the number one cause of death in adults in the industrialized world, and several large studies show that aspirin is helpful for the primary prevention of this disease. Unfortunately, few physicians are aware of its benefit, resulting in the underutilization of aspirin for the primary prevention of CHD. The purpose of this study was to demonstrate the underuse of aspirin for the primary prevention of CHD, and to improve appropriate utilization by implementing an easy-to-use clinic tool that quickly estimates a patient’s risk. Patients and Methods: This is a retrospective cohort analysis conducted in the Internal Medicine Clinic in the Naval Medical Center in San Diego, California. Random samples of 494 patients before and 593 after intervention who were followed in the Internal Medicine Clinic were screened. Inclusion criteria were a 10-year risk of myocardial infarction or coronary death of more than 10%, or diabetes with one other cardiac risk factor. A poster was placed in each clinic examination room showing the Framingham Risk Score, the indications for aspirin use, and common contraindications to assist physicians in determining if a patient warranted aspirin for primary prevention of CHD. A physician documented regular use of aspirin, 81 to 325 mg per day. Results: Age and sex demographics were similar between the two measurement groups. Diabetics comprised a significantly greater

From the Departments of Internal Medicine and Cardiology, Naval Medical Center, San Diego, CA. Reprint requests to Dr. Steven Romero, c/o Naval Health Clinic Great Lakes, 3001A Sixth Street, Great Lakes, IL 60088. Email: [email protected] med.navy.mil Supported by Grant No. NSHSBETHINST 6000.41B from the Chief, Bureau of Medicine and Surgery, Navy Department, Washington, DC. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government. Drs. Romero and Dela Rosa have no financial disclosures to declare. Dr. Liaz owns stock in Pfizer and Novartis. Accepted December 6, 2007. Copyright © 2008 by The Southern Medical Association 0038-4348/0⫺2000/10100-0725

Southern Medical Journal • Volume 101, Number 7, July 2008

MD,

and Peter E. Linz,

MD, FACC

percentage of patients in the postintervention group. There was a trend toward increase in utilization of aspirin from 63.5% to 72.8% (P ⫽ 0.054) after our intervention. In subgroup analysis, significant improvement in appropriate aspirin use was found amongst males (P ⫽ 0.01) and nondiabetics (P ⫽ 0.02). Conclusion: Aspirin has proven beneficial in the primary prevention of CHD, but is clearly underutilized in this role. By implementing the Framingham Risk Score to streamline the decision process, appropriate utilization can be improved, and in turn, cardiac events can be reduced and patients can benefit. Key Words: aspirin, coronary heart disease, Framingham Risk Score, prevention

C

oronary heart disease (CHD) is the number one cause of death in adults in the industrialized world (Table 1). It is well proven that aspirin reduces the risk of coronary events by irreversibly acetylating platelet cyclooxygenase, which would otherwise catalyze the production of thromboxane A2, vital for platelet activation. Over 18 years ago, the US Physicians Health Study first demonstrated the benefit of aspirin for the primary prevention of CHD. This was a randomized, double-blind, placebocontrolled study looking at the rate of first myocardial infarc-

Key Points • Aspirin has proven to be an inexpensive, well-tolerated preventive measure, and has the potential to substantially reduce the incidence of major cardiac events. • The use of aspirin for primary prevention of coronary heart disease is underutilized and needs to be emphasized more in general clinical practice. • With the use of the Framingham Risk Score, the appropriate use of aspirin can be improved and in turn have a real impact on our patients and health care system.

725

Romero et al •Aspirin for Primary Prevention of Coronary Heart Disease

Table 1. Leading causes of death in the US: year 2003 (Source: National Center for Health Statistics Vital Statistics System) Cause of death Heart disease Malignant neoplasms Cerebrovascular disease Chronic lower respiratory disease Accidents

Percent of US population 28.0%, 685,089 22.7% 6.4% 5.2% 4.5%

tion (MI) among 22,071 male physicians treated with mediumdose aspirin (325 mg every other day); those taking aspirin showed a 44% reduction in risk of first myocardial infarction over 5 years.1 In 1998, the Hypertension Optimal Treatment Study Group compared the rate of cardiovascular events in 18,790 patients with hypertension treated with daily aspirin (75 mg every day) or placebo and showed significant reductions in both major cardiovascular events (15%, P ⫽ 0.03) and myocardial infarction (36%, P ⫽ 0.002) in patients taking aspirin.2 Current guidelines, as described below, recommend the use of aspirin in patients with a Framingham Risk Score (FRS) corresponding to a 10-year risk of MI or coronary death greater than 10%. The development of the FRS in 1991 and its validation in 2001 provide a useful tool to estimate a patient’s future risk.3 The FRS proves especially helpful when judging the potential risks and benefits of aspirin treatment for an individual patient without known CHD. A meta-analysis done by Sanmuganathan in 2000 showed a number neededto-treat (NNT) of 67 to prevent one MI over 5 years in patients with a 10-year risk more than 10%.4 A more recent meta-analysis of 55,580 patients, made up in part by the first two above-mentioned studies, showed a 32% reduction of risk of first MI in patients with a 10-year risk more than 10%, thereby lending strong support for the use of aspirin for the primary prevention of coronary heart disease.5 The US Preventive Services Task Force “strongly recommends” that clinicians discuss the regular use of aspirin for primary prevention of CHD with all patients with a 10year risk more than 6%.6 Guidelines from the American Heart Association (AHA) recommend aspirin for patients with a 10-year risk more than 10%.7 The American Diabetes Association (ADA) recommends aspirin for individuals with diabetes who are over 40 years of age or who have one other cardiac risk factor.8 Physician awareness of these guidelines appears low, and less commonly employed than other primary prevention measures. It was our hypothesis that few physicians are aware of these guidelines, which results in the underuse of aspirin, and that by implementing an easy-to-use tool in the

726

Fig. 1 Preintervention sample. clinic setting to estimate a patient’s risk, we could improve appropriate utilization of aspirin for the primary prevention of CHD.

Patients and Methods Subsequent to the receipt of Institutional Review Board approval, we reviewed the medical records of 494 patients seen in the Internal Medicine Clinic at the Naval Medical Center San Diego between April 1 and June 30, 2003 by their respective primary care physicians for a routine appointment (Fig. 1). We excluded those 294 patients that had either very low risk for CHD, prior indication for aspirin, significant bleeding risk, or other miscellaneous reasons (Table 2). Two hundred patients met our inclusion criteria: FRS corresponding to a 10-year risk more than 10%, or diabetes mellitus plus one other cardiac risk factor. We then measured the percentage of these patients that were actually receiving aspirin based on physician documentation. In November 2003, we placed an 11 ⫻ 14 inch poster that included the FRS (Fig. 2) in each examination room of the Internal Medicine Clinic to assist physicians in judging whether patients warranted the use of aspirin for the primary prevention of CHD. We encouraged physicians by infrequent, brief announcements at departmental meetings to utilize the Table 2. Exclusion criteria Reason Prior indication Low risk Bleeding risk

Miscellaneous

Examples History of coronary artery disease History of ischemic stroke or transient ischemic attack 10-yr risk ⬍10% Not diabetic with one other risk factor History of hemorrhagic stroke Upper gastrointestinal bleed within 1 yr Treated with warfarin or clopidogrel Bleeding disorder Aspirin allergy Inadequate data in medical record Already in another study (ACCORD, DREAM, etc.)

ACCORD, Action to Control Cardiovascular Risk in Diabetes; DREAM: Diabetes Reduction Assessment with Ramipril and Rosiglitazone Medication.

© 2008 Southern Medical Association

CME Topic

Fig. 2 Clinic tool used to determine Framingham Risk Score and appropriate use of aspirin. tool to improve compliance with established guidelines and to decrease future likelihood of coronary events. After the intervention, we reviewed the outpatient medical records of another random sample, this time of 593 patients seen for a routine appointment by their primary care physician in the Internal Medicine Clinic over the

3-month period of October 1– December 31, 2004 (Fig. 3). We excluded 391 patients for the reasons described above and then measured the rate of aspirin use in the remaining 202 patients. The primary outcome measure was the use of aspirin, 81 to 325 mg daily.

Statistical Analysis The Mann-Whitney rank-sum test was used to compare median age between the two groups. The Fisher exact test was used to compare the baseline characteristics and the rate of aspirin use between the two groups.

Results

Fig. 3 Postintervention sample. Southern Medical Journal • Volume 101, Number 7, July 2008

There was no significant difference in age or sex in the baseline characteristics of our two groups (Table 3). Median age was 71 in both groups (P ⫽ 0.31), and males comprised 62.0% and 54.5%, respectively, in the two

727

Romero et al •Aspirin for Primary Prevention of Coronary Heart Disease

Table 3. Baseline characteristics Preintervention (n ⴝ 200) Median Age (yr) Sex Male Female Diabetes mellitus

Postintervention (n ⴝ 202)

71 124 (62.0) 76 57/200 (28.5)

P

71

0.31

112 (54.5) 90 102/202 (50.5)

0.13 ⬍0.01

All values inside parentheses indicate percentages.

groups (P ⫽ 0.13). There was a greater percentage of diabetic patients in our postintervention group (50.5 versus 28.5%, P ⬍ 0.01). In our entire 1,087 patient sample, 402 (37%) were found to be good candidates to receive aspirin for primary prevention of CHD based on current guidelines. Aspirin was used for primary prevention of CHD in 63.5% (127/202) of patients in our preintervention sample (Table 4). After our intervention, the rate of aspirin use was found to be 72.8% (147/202). This represents a 9.3% (P ⫽ 0.054) absolute increase in the rate of aspirin use for primary prevention of CHD. A subgroup analysis based on sex and the presence of diabetes mellitus showed a significant improvement in aspirin utilization in males (P ⫽ 0.01) and nondiabetic patients (P ⫽ 0.02).

Conclusion Several major studies have convincingly proven that the regular use of aspirin decreases the risk of MI or coronary death, even in patients without a prior history of CHD.1– 4 Unfortunately, many physicians are neither aware of its proven benefit for primary prevention nor the existence of guidelines from major bodies identifying which patients would benefit from the therapeutic effects of aspirin. We found a suboptimal rate of use of aspirin for the primary prevention of CHD, 63.5% in our clinic population. We demonstrated that with the implementation of a simple, inexpensive clinical tool utilizing the Framingham Risk Score

Overall aspirin use Males Females Diabetic Nondiabetic

127/200 (63.5) 76/124 (61.3) 51/76 (67.1) 49/57 (86.0) 78/143 (54.5)

147/202 (72.8) 85/110 (77.3) 62/92 (67.4) 78/102 (76.5) 69/100 (69.0)

All values inside parentheses indicate percentages.

728

References 1. Steering Committee of the Physicians’ Health Study Research Group. Final report on the aspirin component of the ongoing physicians’ health study. N Engl J Med 1989;321:129 –135. 2. Hansson L, Zanchetti A, Carruthers SG, et al. Effects of intensive bloodpressure lowering and low-dose aspirin in patients with hypertension: principal results of the hypertension optimal treatment (HOT) randomised trial. Lancet 1998;351:1755–1762. 3. D’Agostino RB Sr, Grundy S, Sullivan LM, et al. Validation of the Framingham coronary heart disease prediction scores: results of a multiple ethnic groups investigation. JAMA 2001;286:180 –187.

Table 4. Comparison of aspirin use Preintervention Postintervention (n ⴝ 200) (n ⴝ 202)

(Fig. 2), the rate of aspirin use could be improved, although our data were of borderline statistical significance. Why the use of aspirin was found to improve more in nondiabetic patients is not clear, but in men was probably related to the fact that age greater than 70 years, by itself, equated to a 10-year risk greater than 10%. If our data can be extrapolated to our entire clinic population of roughly 8,000 patients, then 2,959 (37% of 8,000) are good candidates for aspirin for primary prevention of CHD. Having increased the rate of use by 9.3% with our intervention, we should now have 275 (9.3% of 2,720) more patients appropriately on aspirin. Based on the previously stated NNT of 67, we will have prevented at least four (275/ 67) major cardiac events over the next five years. The potential benefit is even greater if our overall compliance rate could be improved to approach 100%. This study is limited by a relatively small sample size and a significantly higher rate of diabetes in our second measurement group, most likely related to using different random samples before and after our intervention. Also, the primary endpoint measurement was based solely on physician documentation, and may not accurately reflect actual patient use of aspirin. Lastly, our study did not take into account more recently available gender-specific recommendations for the use of aspirin for primary prevention. Aspirin has proven to be an inexpensive, well-tolerated preventive measure, and it has the potential to substantially reduce the incidence of major cardiac events. Clearly, the use of aspirin for primary prevention of CHD is underutilized and needs to be emphasized more in general clinical practice. With the use of the Framingham Risk Score, the appropriate use of aspirin can be improved and in turn have a real impact on our patients and healthcare system.

P 0.054 0.01 1.0 0.22 0.02

4. Sanmuganathan PS, Ghahramani P, Jackson PR, et al. Aspirin for primary prevention of coronary heart disease: safety and absolute benefit related to coronary risk derived from meta-analysis of randomised trials. Heart 2001;85:265–271. 5. Eidelman RS, Hebert PR, Weisman SM, et al. An update on aspirin in the primary prevention of cardiovascular disease. Arch Intern Med 2003;163:2006– 2010. 6. Guide to clinical preventive services: report of the US preventive services task force, 3rd ed., U.S. preventive services task force, 2000 –2002. 7. Pearson TA, Blair SN, Daniels SR, et al. AHA guidelines for primary prevention of cardiovascular disease and stroke: 2002 update: consensus

© 2008 Southern Medical Association

CME Topic

panel guide to comprehensive risk reduction for adult patients without coronary or other atherosclerotic vascular diseases. American Heart Association Science Advisory and Coordinating Committee. Circulation 2002;106:388 –391. 8. Buse JB, Ginsberg HN, Bakris GL, et al. Primary prevention of cardiovascular diseases in people with diabetes mellitus: a scientific statement

from the American Heart Association and the American Diabetes Association. Circulation 2007;115:114 –126.

Please see Dr. Shannon W. Fink’s editorial on page 679 of this issue.

“Who has never killed an hour? Not casually or without thought, but carefully: a premeditated murder of minutes. The violence comes from a combination of giving up, not caring, and a resignation that getting past it is all you can hope to accomplish. So you kill the hour. You do not work, you do not read, you do not daydream. If you sleep it is not because you need to sleep. And when at last it is over, there is no evidence: no weapon, no blood, and no body. The only clue might be the shadows beneath your eyes or a terribly thin line near the corner of your mouth indicating something has been suffered, that in the privacy of your life you have lost something and loss is too empty to share...” —Mark Z. Danielewski, House of Leaves

Southern Medical Journal • Volume 101, Number 7, July 2008

729

Suggest Documents