Family Physician’s Knowledge, Beliefs, and Self-reported Practice Patterns Regarding Hyperlipidemia: A National Research Network (NRN) Survey

Methods

A survey consisting of 32 items was developed in an iterative fashion by the study investigators and pretested in the fall of 2003 with 155 survey respondents (representing a 60% response rate) who were physician members of the American Academy of Family Physicians (AAFP) National Research Network (NRN). After analyzing the responses, we added some questions, deleted others, revised the wording of selected items, and reformatted others. We included 4 short clinical scenarios to assess physicians’ management of: (1) a patient with an elevated low-density lipoprotein (LDL) cholesterol despite maximal dose of a statin, (2) a patient with type 2 diabetes mellitus on a moderate dose of a statin and inadequate lipid control, (3) elevated liver function tests in a patient on a statin, and (4) elevated creatinine phosphokinase (CPK) in a patient on a statin. Response categories were multiple choice or written answers, except for open-ended responses to 2 questions: “What are the two or three greatest barriers you face in assessing coronary heart disease risk in your patients?” and “What are the two or three greatest barriers you face in treating your patients with hyperlipidemia?”

In April of 2004 we mailed the revised 33-item survey to a random sample of 1200 active members of the AAFP who resided in the United States and who had previously reported at least 50% of their professional effort in direct patient care (AAFP master database). We sent up to 2 follow-up surveys to nonrespondents.

This study was not designed for hypothesis testing, and therefore, the analyses are purely descriptive. The sample size of 1200 was large enough by conventional standards8–10 to adequately describe this population within an acceptable margin of error for both 5-point Likert scale items (95%, ±.12, estimated variance = 2.0), and dichotomous survey items (95%, ±5.0%, estimate P = .50), both assuming a 50% response rate, which was achieved. We used SPSS, version 11.5.111 for the analyses, and included summary descriptions of demographic data and frequency data of survey answers. The study was approved and designated exempt by the University of Missouri-Kansas City Social Science Institutional Review Board.

Results

Thirty-five (3%) surveys were returned with wrong addresses or ineligible practice status, reducing the sample size to 1165. There were 677 completed surveys (58%) of which 641 were available for analysis—these respondents provided survey data on their “percentage of time in direct patient care” of more than 50%. The remaining 36 respondents either did not answer this question (n = 21) or reported this percentage to be less than 50% (n = 15). Table 1 summarizes the demographic characteristics of the respondents.

Survey participants spent, on average, 89% (SD = 12) of their professional effort on clinical practice, 8% (SD = 9) on administration, 3% (SD = 5.7) on teaching, and less than 1% (SD = 1.4) on research. Based on bivariate statistical comparisons between survey respondents and the population of AAFP active members on available demographic characteristics taken from the AAFP master database, the 2 groups did not differ statistically on age (47.3 versus 46.9, Z = 1.13, P > .05), years in practice (19.3 versus 18.9, Z = 1.24, P > .05), gender (χ² = 0.01, P = .904), geographic region (χ² = 3.14, P = .370), and practice location (χ² = 1.40, P = .998).

Discussion

This is an important study because it provides insight into the self-reported practice patterns of family physicians, one of the largest groups of clinicians providing preventive services for cardiovascular disease and hyperlipidemia in the United States. This study demonstrates that many but not all recommendations of the new ATP III guidelines have been adopted in clinical practice by most family physicians that are members of the AAFP. It also demonstrates the large degree of practice variation regarding cholesterol assessment and management and, therefore, much room for improvement.

Nearly all family physicians responding to this survey reported that they routinely assess adult patients without established cardiovascular disease for coronary risk. This is a higher degree of screening than found in previous studies but compares favorably with recent data obtained from chart abstraction in primary care settings.12 Most risk assessment is performed by the physician without the support of flow sheets, decision aids, or support personnel. Only a minority of family physicians stated they used a risk calculator always or usually when risk stratifying a patient. Of those reporting use of a calculator, the majority used a paper format but a large minority reported using an electronic calculator. Thus recommendations of using a systematic team-based approach in organizing CHD risk factor assessment have not yet penetrated clinical practice.13

In addition, the recommendation of the ATP III to risk stratify patients using their 10-year risk of CHD does not seem to have been adopted by most physicians in this study. A recent Internet survey commissioned by the National Lipid Association of Physicians (n = 200) found that most physicians (81%) surveyed reported being very familiar with the NCEP guidelines, and 73% felt that they adhered to them but perceived that only 46% of other physicians were very familiar with these guidelines and only 33% of them were adherent.14 The second estimate is more compatible with the data reported here. Another Internet study of 300 primary care physicians in 2004 found that 95% of physicians were aware of the ATP III guidelines, but less than 50% of primary care clinicians correctly identified low-risk and intermediate-risk patients. Use of pharmacotherapy for high-risk patients was recommended in over 95% of the cases by primary care physicians in this second survey.15

The age at which family physicians in our survey begin screening seems to lie between the ages recommended by the ATP III guidelines and the U.S. Preventive Services Task Force. The ATP III recommends screening at age 20 or older, whereas the U.S. Preventive Services Task Force recommends that screening begin at age 35 for men and at age 45 for women.16

Nonetheless, the U.S. Preventive Services Task Force recommendations also state that earlier screening is indicated for patients at higher risk (eg, diabetes, smoking, patients with cholesterol disorder, etc). The physician-reported gender differences in screening observed in our survey probably reflect these disparate clinical recommendations.

The frequency of primary care visits seems fairly uniform for both well-controlled (average 2.2 visits per year) and uncontrolled hyperlipidemic (4.2 visits per year) patients. Alternatively, the levels at which medications are stopped due to biochemical abnormalities shows a great deal of variability. Many surveyed physicians seem to be conservative and do not follow the FDA package insert or the National Cholesterol Guideline recommendations but rather report stopping lipid-lowering medications at low levels of biochemical abnormalities. This finding suggests that many family physicians are either unaware of the guideline recommendations or have adapted these recommendations to patient concerns or an individualized style of practice. The case scenarios of “second steps” in management of high-risk hyperlipidemic patients who are not at NCEP goals show a wide range of practice patterns. The observed variability in responses is not surprising given the lack of clear benefit to any particular therapeutic approach. The low use of plant stanol/sterol esters, fibrates, and lipid specialist referral, and the high reported use of cholesterol absorption inhibitors, and increasing doses of statins are of interest for those desiring a better understanding of how family physicians manage their difficult-to-control hyperlipidemic patients.

Family physicians believe that the majority of barriers to assessment and treatment are patient factors. Cost, adherence, and patient beliefs, attitudes, and health habits account for approximately 50% of the barriers to assessment and almost 75% of the barriers to treatment (Table 5). These findings are similar to those found in a recent Internet survey of clinicians14 where 61% of respondents in that survey believed that many patients were concerned about potential side-effects of prescription drugs. A total of 59% of physicians stated that many patients were unable to afford prescription drugs, and 58% stated that many patients do not comply with long-term cholesterol-lowering drugs. These same investigators, however, found quite different responses from consumers, with only 31% fearing the side-effects of cholesterol-lowering medication, 34% stating that medications cost too much, 28% not liking to take prescription medications, and 58% willing to control cholesterol with diet and exercise. We believe that clinicians would do better by focusing on the barriers they can ostensibly influence, such as establishing standard assessment and treatment protocols in their offices, using risk calculators regularly to guide treatment, and using a team approach to ensure that all adult patients are appropriately assessed and treated.

Previous work using chart audits indicates actual lipid management may not be as good as physicians report it to be. Eaton et al12 showed that in 5 community family practices in southeastern New England in 2003, only 23% of CHD equivalent-risk patients were at an LDL goal <100 mg/dL and 42% of high-risk patients were at an LDL goal <130 mg/dL. Pearson et al17 evaluated 5 regions of the United States (lipid treatment assessment project [L-TAP]) and found that only 38% of patients met their LDL goals, and only 18% of established CHD patients were at their LDL goal.

Examining only high-risk women in a 1.1 million member-integrated managed care program, Mosca et al18 found only 7% at LDL goal <100 mg/dL initially with an increase to 12% after 36 months. These treatment gaps—despite clinician statements that they treat most of their high-risk patients to goal—are hard to reconcile as largely patient-related barriers as our survey would suggest. Quality improvement projects focusing on a team-based system approach have demonstrated improvement in the number of hyperlipidemia patients at goal.19

We recognized a number of limitations to our study. The sampling frame was United States AAFP members who spent at least 50% of their time in direct patient care (according to the AAFP membership database and self-reports obtained in this survey), so the results may not apply to physicians who spend less time in patient care or to other primary care physicians. Our response rate of 58% is good for this population, but the results may not reflect the practices and beliefs of nonrespondents. The most important reason for refusal to complete a survey is lack of interest in the subject.20,21 Therefore, it is likely that family physicians who completed the survey were more interested in and knowledgeable about hyperlipidemia than those who did not. With few exceptions, survey respondents were very comparable statistically both to nonrespondents and to the larger AAFP active member population on available individual and practice demographics from the AAFP master database (results available from JMG).

Our data also are self-reported, and as discussed above, there may be discrepancies between what physicians self-report about their practice patterns and their actual behavior. We did not determine the actual practice patterns of the surveyed family physicians.

Conclusion

The results of this survey demonstrated variability in knowledge, beliefs, and practice patterns among practicing family physicians. We found general agreement on universal screening of adults for hyperlipidemia as part of cardiovascular disease prevention strategy and use of LDL cholesterol as a treatment goal especially for diabetics and patients with established coronary and non-coronary atherosclerotic disease. Many other aspects of the NCEP ATP III guidelines, such as use of a systematic, multidisciplinary approach, using non-HDL-cholesterol as a secondary goal, using a CHD risk calculator for risk assessment to guide cholesterol management, and use of combination therapy for patients not at their LDL goals, have not yet penetrated self-reported clinical practice. This insight may be helpful in designing quality improvement projects aimed at improving optimal cholesterol management in primary care. Given the prevalence of cardiovascular disease in the United States, the estimates of increase in this prevalence over time, and the large numbers of patients-at-risk seen routinely by family physicians, these same physicians would do well to understand and implement the recommendations of the U.S. Preventive Services Task Force and NCEP ATP III to better manage patients with risk factors for cardiovascular disease.