Cardiovascular disease (CVD) remains the number one cause of death in the United States. Numerous advances in medical therapy and diagnostics have occurred for prevention and treatment of CVD. In order to standardize clinical practice and simplify clinical decision making in reducing CVD risk, clinical guidelines have been published and are available: the American Heart Association/American College of Cardiology 1, National High Blood Pressure Education Program committee (JNC 7) 2, and National Cholesterol Education Panel (ATP III) 3. Yet, despite efforts to reduce the risk of CVD among at risk Americans, recent observation and survey studies show that considerable gaps in knowledge and application of guideline recommendations for risk reduction remain 456789. A key factor in proper CVD risk management is accurate risk assessment; however inconsistencies among current methods for calculating risk 10 and the perception of risk among health care providers contribute to challenges in risk assessment 711. Results from several studies demonstrate that treatment strategies have not achieved blood pressure and lipid profile goals in women, African Americans, Hispanic Americans, young people, and patients with co-morbidities 121314151617181920. While the benefits of reducing blood pressure in a hypertensive patient are obvious 2, multiple studies have shown that more than 40% are satisfied with blood pressures higher than the recommended goal 21222324. The objectives of this study were to: 1) assess the knowledge, attitudes and identify barriers to optimal CVD prevention among US primary care physicians; 2) examine the association between physician characteristics and their knowledge and attitudes.

We performed a case vignette survey of U.S. primary care physicians between November and December 2006. Surveys were distributed by fax and electronic mail to a random sample of 12,000 board-certified family physicians and general internists. Participants were offered a $20 gift card to complete the study. For this study, respondents who saw 60 or more patients per week were considered active physicians. Of 1,025 responses (8.5% response rate), 888 met the criteria as an active family physician or general internist and saw 60 or more patients per week.

The main findings from this study were that guideline concordance in managing low and high risk CVD patients by primary care physicians significantly varied in treatment and dietary approach, and managing patients according to guidelines was associated with years in practice and volume of patients. For a low-risk female patient about one third of primary care physicians followed guidelines to not initiate antiplatelet therapy. These findings are similar to other studies reporting differences in management approach by risk level assessment by physicians 721. In a study of 300 primary care physicians, Mosca et al. found that 32% will prescribe aspirin for a low-risk patient 7. Additionally, for a 50-year-old high risk patient 40% did not indicate a guideline recommended LDL goal in accordance with his risk level. Results of recent clinical trials, however, suggest that the lower the serum LDL-cholesterol level, the more the benefits in preventing cardiovascular events 3031. The recognition and appropriate management of low- and high-risk patients is critical especially by primary care physicians because in many cases, especially in underserved areas, they serve as the only source of care.

In terms of dietary recommendations, our study found that over one-third of primary care physicians failed to recommend reducing trans fatty acid intake for CVD prevention in a low risk patient. This finding is consistent with other studies showing a lack of guideline-based dietary recommendations by primary care physicians 7. A plausible cause for this finding may be that nearly 50% of physicians indicated that their and their staff's knowledge and skills to provide dietary recommendations is a significant barrier in their practice. Innovative educational interventions and practical screening tools to calculate CVD risk may be useful to overcoming this barrier.

It is noteworthy that two main characteristics of primary care physicians were associated with greater guideline concordance. Physicians who have been in practice for 10 years or less and physicians who managed a small number of patients with hypertension and dyslipidemia (25% or less) were significantly more likely to make practice choices in accordance to guidelines. These findings are consistent with results of a systematic review conducted by Choudhry and colleagues which suggested an inverse relationship between years in practice and the quality of care provided 32; other studies suggest that older physicians are more likely to be aware and incorporate guidelines to practice 11.

Reverse relationship between guideline adherence and patient volume is especially concerning in that physicians' who see a greater percentage of hypertensive and dyslipidemic patients are not providing care according to standards. Younger physicians are more likely to adhere to guidelines than more experienced physicians. A plausible explanation for this finding is that it may be more difficult for older physicians to overcome previous practice inertia 2433. A review by Cabana and colleagues suggest a variety of other reasons (not related to physician's age) why physicians may not adhere to guidelines including a lack of knowledge of the guidelines, disagreement with the evidence, and lack of expectations that adherence will result in better patient outcomes 33.

Although clinical practice guidelines were identified by approximately one-third of survey respondents as the most important tool for delivering optimal care to their patients, only a quarter of respondents accept guidelines as the minimum level of evidence for determining an appropriate treatment regimen. Close to 40% indicated that they would accept a level of evidence that is below level A randomized controlled trial or meta-analysis. This, especially in the context where a substantial number of respondents set very aggressive lipid goals that are in line with recent trial data, could very well indicate a need for more frequent revisions of clinical practice guidelines as new data emerges. More frequent updates of the guidelines could increase physician confidence in the recommendations and improve physician adherence.

Finally, an interesting finding in our study was that 25% of primary care physicians selected CME activities as the most important tool in helping them improve patient care. CME was rated above clinical practice guidelines in keeping physicians up-to-date. Physicians expressed that they would prefer CME content that is patient-centered and that provides strategies for daily practice, rather than information on trial methodology and data.

There are several limitations to this study. First, this study used a survey as a surrogate measure of primary care physicians' knowledge and attitudes that was self-reported. However, the use of case vignettes has been shown to provide good insight into physicians' actual practice patterns 25262728. Second, only four clinical scenarios were used which do not cover the full spectrum of cardiovascular risk. We specifically examined recognition of cardiovascular risk, goal setting, and treatment recommendations. Future studies are needed to examine more specific areas of cardiovascular risk recognition and if practice choices will vary according to other relevant variables such as patients' health insurance status, patient gender and race, and socioeconomic status that may be strong determinants of clinical choices. Additionally, respondents were given a small honorarium to complete the study, which could influence physician participation rates and responses. The cross-sectional design of the study does not allow for causal inferences to be drawn and future study designs such as cohort and longitudinal designs are needed. Finally, the majority of practitioners were in private practice and the impact of a managed care environment on adherence to guidelines was not evaluated. Managed care restrictions and penetration may influence practice choices and attitudes of physicians in how they treat patients.

In conclusion, despite the benefits demonstrated for managing cardiovascular risks, gaps remain in primary care practitioners' management of risks according to guideline recommendations. Innovative educational approaches are needed to address barriers, and target specific groups of physicians to facilitate the implementation of guideline-based recommendations in CVD management.

The authors declare that they have no competing interests.

HD participated in the design of the study and drafted the manuscript. EF, KS, MT, KS participated in the development of the survey instrument and reviewed the manuscript. MA performed the statistical analysis and drafted the methods section of the manuscript. JF participated in the review of the manuscript and the writing of the discussion section. LC participated in the design of the study. All authors read and approved the final manuscript.