Volume 102, Issue 9 , Pages 1142-1145, 1 November 2008
Discordance Between Physicians' Estimation of Patient Cardiovascular Risk and Use of Evidence-Based Medical Therapy
Article Outline
Despite clinical trial evidence supporting the use of antiplatelets, angiotensin-converting enzyme inhibitors, and statins for cardiovascular risk reduction in high-risk patients, use of such therapies in real-world outpatients in the prospective Vascular Protection Registry and the Guidelines Oriented Approach to Lipid Lowering Registry was suboptimal (78%, 55%, and 75%, respectively). The most frequent reason physicians cited for nonprescription of statins (33%) was that patients were not high risk enough and/or current guidelines did not support statin use. In conclusion, outpatients at high cardiovascular risk continue to be undertreated as a result of a combination of physician underestimation of cardiovascular risk (knowledge gap) and barriers to implementation of evidence-based therapy (practice gap).
Numerous therapies are effective in reducing morbidity and mortality in patients with cardiovascular risk factors and cardiovascular diseases, including antiplatelets, angiotensin-converting enzyme (ACE) inhibitors, and statins. Thus, current management guidelines recommended the use of these and other therapies1, 2 for primary and secondary prevention of cardiovascular diseases. Although there were extensive reports documenting underuse of these therapies, the reasons physicians failed to prescribe them are unclear. In the present study, we described the use of antiplatelets, ACE inhibitors, and statins in the outpatient setting based on 2 large Canadian registries: the Vascular Protection (VP) Registry and the Guideline Oriented Approach in Lipid Lowering (GOALL) Registry. Uniquely, we reported the reasons provided by physicians for why they did not prescribe these evidence-based medical therapies to their patients.
Methods and Results
The VP and GOALL Registries were prospective observational outpatient practice-based registries designed, implemented, and managed by the Canadian Heart Research Centre (Toronto, Canada; a federally incorporated nonprofit academic research organization). The purpose of these registries was to monitor management and outcomes in patients at high risk of vascular events (3% to 5%/year average risk of a severe cardiovascular event) and identify gaps between patient care recommended in guidelines and that delivered in the “real world.” Overall, 278 and 254 physicians (>95% were family/general practitioners) from 9 provinces voluntarily participated in the VP (December 2001 to November 2004) and GOALL (December 2002 to December 2004) Registries, respectively. The study was approved by 2 ethics review boards (Research Ethics Review Committee of the College of Physicians and Surgeons of Alberta, Edmonton, Alberta; and Research Ethics Review Board of Optimum Clinical Research Inc., Oshawa, Ontario, Canada).
As previously published,3, 4, 5, 6 both registries had similar inclusion criteria, adapted from the Heart Outcome Prevention Evaluation (HOPE) Study.7 Men and women were eligible for enrollment if they had ≥1 of (1) coronary artery disease, defined as the presence of ≥1 of previous myocardial infarction, unstable angina, coronary revascularization (coronary artery bypass surgery or percutaneous coronary intervention), or stable angina with either an angiogram showing >50% stenosis in ≥1 major coronary artery or a positive stress test result; (2) cerebrovascular disease, defined as a documented history of stroke or transient ischemic attack; and (3) peripheral vascular disease, defined as a history of intermittent claudication or a documented decrease in pulses or bruits supported by an ankle-brachial index <0.9 or duplex ultrasound diagnosis (>50% stenosis in ≥1 major artery). In the absence of overt atherosclerotic disease, in the VP Registry, diabetic patients with ≥1 other cardiovascular risk factor (systolic blood pressure >140 mm Hg, diastolic blood pressure >90 mm Hg, or use of antihypertensive medication; total cholesterol >5.2 mmol/L or high-density lipoprotein cholesterol <0.9 mmol/L; current cigarette smoking; or microalbuminuria) were also eligible. The GOALL Registry also included diabetic patients and/or older patients (age >65 years) with ≥2 risk factors (as listed). The presence of diabetes was ascertained based on the current standard diagnostic criteria, previous diagnosis of diabetes by a physician, or use of antihyperglycemic medications or insulin. There were no exclusion criteria in either registry.
Data were collected at each participating site by physicians who completed a standardized baseline case report form. Each patient was then followed up at 6 (in both the VP and GOALL Registries) and 12 months (in the VP Registry) as part of routine clinical care. Forms were returned to the Canadian Heart Research Centre and scanned into an electronic database using a modified Teleform, version 7.0 (Cardiff Software Inc., San Diego, California). Quality control measures ensured that queries regarding incomplete or unclear data were returned to sites for necessary correction or clarification. For analyses of medication use at 6 months before enrollment (n = 5,096) and 12-month follow-up (n = 4,149), only data from the VP Registry were available. For analyses of medication use at baseline (n = 9,810), data from both the VP and GOALL Registries were available. For analysis of reasons why patients were not on evidence-based/guideline-recommended therapies, all 254 physicians participating in the GOALL Registry completed information as part of the case report form (CRF) for patients not receiving statins after the baseline visit (n = 1028). In the VP Registry, physicians who had enrolled ≥5 patients from November 2002 to July 2003, were asked to complete a supplementary CRF for patients not receiving antiplatelet and/or ACE-inhibitor and/or statin therapy after the baseline visit. A total of 110 of 168 physicians caring for 1,827 of the 2,439 patients not on ≥1 of those therapies responded.
The primary analysis focused on the use of antiplatelet agents, ACE inhibitors, and statins, and when available, reasons why physicians chose not to prescribe these therapies. All values were summarized as percentage for categorical variables and median with interquartile range for continuous variables. All tests were 2 sided and considered significant at p <0.05. Statistical analysis was carried out using SAS, version 8.2 (SAS Institute Inc., Cary, North Carolina), and SPSS, version 12.0 (SPSS Inc., Chicago, Illinois).
In total, 6,251 patients with cardiovascular diseases were available for analysis. Overall, there was suboptimal use of antiplatelets, ACE inhibitors, and statins (78%, 55%, and 75%, respectively). When physicians were asked why their individual patients were not prescribed antiplatelets, 36% of patients were subsequently prescribed an antiplatelet agent after prompting the physicians to provide a reason why their patient was not using acetylsalicylic acid after enrollment. Only 4% of patients not receiving an antiplatelet agent were believed to be not high risk enough or that current guidelines did not support antiplatelet use (Table 1).
Table 1. Reasons that patients (Vascular Protection Registry) were not on antiplatelet therapy (n = 523)
| Reason | Patients |
|---|---|
| Patients were not high risk enough and/or current guidelines did not support use | 4% |
| Intolerance/allergy | 11% |
| Noncompliance | 7% |
| Bleeding disorder/coagulopathy including anemia | 17% |
| On anticoagulant therapy | 4% |
| Other safety concerns | 15% |
| I have now prescribed this drug | 36% |
The most common reasons provided by physicians why patients were not on ACE inhibitor therapy after enrollment were allergy, intolerance, or hypotension (33%; Table 2). Of note, 21% of patients were prescribed an ACE inhibitor after asking their physician why the patient was not on ACE inhibitor therapy after enrollment. Fourteen percent of patients were thought to be not high risk enough or current guidelines did not support use, and 11% did not receive an ACE inhibitor because the physician stated that the patient had normal left ventricular systolic function.
Table 2. Reasons that patients (Vascular Protection Registry) were not on angiotensin-converting enzyme inhibitor therapy (n = 747)
| Reason | Patients |
|---|---|
| Patients were not high risk enough and/or current guidelines did not support use | 14% |
| Intolerance/allergy/hypotension | 28% |
| Noncompliance | 6% |
| Renal insufficiency/artery stenosis | 3% |
| Normal left ventricular function | 11% |
| On angiotensin receptor blocker therapy | 7% |
| Other safety concerns | 5% |
| I have now prescribed this drug | 21% |
The most common reason that patients were not on statin therapy after enrollment was that patients were not perceived to be high risk enough or current guidelines did not support use (33%; Table 3). Nineteen percent of patients were prescribed a statin after their physicians were asked why these patients had not received a statin after enrollment.
Table 3. Reasons that patients (Vascular Protection and Guidelines Oriented Approach to Lipid Lowering Registries) were not on statin therapy (n = 1,028)
| Reason | Patients |
|---|---|
| Patients were not high risk enough and/or current guidelines did not support use | 33% |
| Intolerance/allergy | 7% |
| Noncompliance | 17% |
| Abnormal liver function test result | 3% |
| Myopathy or creatinine kinase increase | 2% |
| Other safety concerns | 16% |
| I have now prescribed this drug | 19% |
Discussion
In this study, we report the prescription pattern of evidence-based medicine for patients with high cardiovascular risk based on 2 large national outpatient registries. We found that despite ample evidence and guideline recommendations for the use of antiplatelets, ACE inhibitors, and statins in patients at high cardiovascular risk, a significant care gap still exists in Canada. Most importantly, we uniquely described the reasons these high-risk patients were not on appropriate medical therapy according to their treating physicians.
It is important to note that our inclusion criteria and 6-month and 1-year death, myocardial infarction, and stroke composite event rates were similar to those of the HOPE Study.7 This highlighted the relatively high-risk nature of this population and emphasized the need for optimizing evidence-based therapy administration in patients without contraindications to potentially reduce this risk. The rationale for 5%, 14%, and 33% of patients not receiving antiplatelets, ACE inhibitors, and statins was that prescribing physicians did not think these patients were at high enough risk for subsequent events to justify the use of these agents, respectively. This response by physicians highlighted 1 of ≥2 important components of the evidence-to-practice care gap, a knowledge gap caused by lack of awareness of the evidence and/or familiarity with current guidelines.
We also observed that by simply asking physicians why some of their patients were not on a specific therapy led to an approximate 19% to 36% of these patients subsequently being prescribed such therapies. This finding highlighted a second important component of the evidence-to-practice care gap: a practice gap in which some physicians responded to a simple patient-specific prompting to reconsider the use of evidence-based therapies.8 Various tools have been effective in increasing physician performances, including the use of achievable benchmarks for physician feedback,9 local medical opinion leaders,10 community pharmacist intervention,11 and computer-based clinical decision support systems.12 We attempted to implement some of these in our 2 registries, including audit and concurrent feedback targeted to the primary health care provider, reminder systems, and interactive educational meetings.
The strength of our study was that it involved almost 10,000 patients in a national real-world outpatient setting. These registries provided us with a cross-sectional snapshot of how physicians were applying current guidelines. Also, we were able to provide physician-specific insights (based on their individual patients followed up in routine clinical practice) regarding the care gap in the treatment of patients at high vascular risk. These findings give further impetus to the implementation of similar types of quality enhancement initiatives to help close treatment gaps.
The limitations of our study included that our registries enrolled physicians on a voluntary basis, introducing selection bias. However, physicians were instructed to enroll consecutive patients, and the wide inclusion criteria, together with lack of any exclusion criteria, made it likely that a broad range of patients were included. Also, physicians received some form of medical education that focused on evidence/guideline-based management of patients at high vascular risk before patient enrollment. The practice of these physicians was likely different from that of all physicians, and we speculated that our participating physicians were more adherent to guidelines compared with physicians who elected not to participate. Although we were unable to determine the impact of these biases against less motivated physicians and patients, our results were probably conservative and underestimated the prevalence of treatment failure.
In addition, we asked only a selected group of physicians in the VP Registry why some of their patients were not on specific therapy (those who had enrolled ≥5 patients during a specific period in the course of the registry) and only about statin therapy in the GOALL Registry. However, findings were consistent with respect to reasons that statins were not prescribed by physicians in both the subset of physicians in the VP Registry and all physicians in the GOALL Registry (data not shown).
Also, our findings that the most common reason patients were not on evidence-based therapies was the misconception that these patients were not at high enough risk and/or that current guidelines did not support use was also seen in a specialist-based in-patient acute coronary syndrome registry.13 Importantly, evidence-based guidelines for primary and secondary prevention of cardiovascular diseases have changed over time, and in particular, during the enrollment of patients in these 2 registries. Thus, applying current guideline goals to evaluate the quality of practice retrospectively may overestimate physician nonadherence to patient management guidelines.
Finally, although we gave physicians the opportunity to identify specific reasons why they did not prescribe certain therapies (e.g., because of potential contraindications), the case report form and follow-up questionnaire may not adequately identify patients in whom such treatments may be inappropriate or less than ideal despite general evidence-based guideline recommendations.
References
- AHA/ACC guidelines for secondary prevention for patients with coronary and other atherosclerotic vascular disease: 2006 update endorsed by the National Heart, Lung, and Blood Institute. J Am Coll Cardiol. 2006;47:2130–2139
- AHA guidelines for primary prevention of cardiovascular disease and stroke: 2002 update: consensus 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
- . How does the prognosis of diabetes compare with that of established vascular disease? (Insights from the Canadian Vascular Protection (VP) Registry). Am Heart J. 2004;148:1028–1033
- . Vascular Protection Registry and Guideline Oriented Approach in Lipid Lowering Registry Investigators (Supporting a call to action for peripheral vascular disease: insights from two prospective registries). J Vasc Surg. 2006;44:776–781
- Contemporary management of dyslipidemia in high-risk patients: targets still not met. Am J Med. 2006;119:676–683
- Missed opportunities for the secondary prevention of cardiovascular disease in Canada. Can J Cardiol. 2007;23:1124–1130
- . Effects of an angiotensin-converting-enzyme inhibitor, ramipril, on cardiovascular events in high-risk patients (The Heart Outcomes Prevention Evaluation Study Investigators). N Engl J Med. 2000;342:145–153
- . From knowledge to practice in chronic cardiovascular disease: a long and winding road. J Am Coll Cardiol. 2004;43:1738–1742
- . Improving quality improvement using achievable benchmarks for physician feedback: a randomized controlled trial. JAMA. 2001;285:2871–2879
- . Effect of local medical opinion leaders on quality of care for acute myocardial infarction: a randomized controlled trial. JAMA. 1998;279:1358–1363
- A randomized trial of the effect of community pharmacist intervention on cholesterol risk management: the Study of Cardiovascular Risk Intervention by Pharmacists (SCRIP). Arch Intern Med. 2002;162:1149–1155
- . Effects of computer-based clinical decision support systems on physician performance and patient outcomes: a systematic review. JAMA. 1998;280:1339–1346
- . The utilization of cardiac catheterization for non-ST-segment elevation acute coronary syndromes according to initial risk: reasons why physicians choose not to refer their patients. Arch Intern Med. 2008;168:291–296
This work was supported by the Canadian Heart Research Centre, Toronto, Ontario, Canada, Pfizer, Kirkland, Quebec, Canada, Sanofi Aventis, Laval, Quebec, Canada, and Astra Zeneca, Mississauga, Canada. Drs. Leiter, Fitchett, Langer, and Goodman have received speaker/consulting honoraria and/or research grant support from the co-sponsors.
PII: S0002-9149(08)01139-9
doi:10.1016/j.amjcard.2008.06.037
© 2008 Elsevier Inc. All rights reserved.
Volume 102, Issue 9 , Pages 1142-1145, 1 November 2008
