Quality Care and Practice Variation: The Roles of Practice Guidelines and Public Profiles
Curtis E. Margo, MD, MPH

Abstract :
Goals of the quality-of-care initiative are to improve the structure, process, and outcome of health care. The effectiveness of methods to improve quality have been largely unverified. Most methods are costly to implement and time-consuming to perform; some threaten professional autonomy. The characteristic feature of modern medicine that fuels the debate over quality is the variation in the delivery of health care. This review examines the variation phenomenon in medicine and the roles that practice guidelines and physician profiling have in improving health care, in general, and for adult cataract, in particular. (Surv Ophthalmol 49:359371, 2004.  2004 Elsevier Inc. All rights reserved.)

There are few phrases in medicine that evoke as much unanimity of approval and at the same time as much controversy as quality of care. Although the perception of high quality care is an uncontested mission of physicians and medical organizations, the means to achieving this goal are the subject of seemingly endless debate and interpretation.

The growing reliance of quality assessment practices in determining clinical privileges, obtaining insurance contracts and reimbursements, and in malpractice litigation emphasizes the need to understand what quality means, how it is measured, and if it can be improved.

The concept of quality care has multiple components. Achieving successful quality is judged by how well the dimensions of clinical care conform to expectations and standards. The sources of these expectations and standards are generally derived from several sources including the science of medicine that determines efficacy, individual values that determine acceptability, and social and institutional expectations that determine legitimacy.

Although the professional ideal of quality is incontrovertible, some of the practices used to influence clinician behavior in the name of quality have not been uniformly accepted by the medical profession. This review will examine two processes used to improve quality of care: practice guidelines and physician profiling. They will be examined in historical context and in their application to cataract surgery. Despite their apparent differences, these processes are an outgrowth of what may be the most compelling rationale behind the quality-of-care initiative: clinical practice variation, also known as the variation phenomenon.

Definitions
The Institute of Medicine describes quality care as the degree to which health services for individuals The Institute of Medicine describes quality care as the degree to which health services for individuals and populations increase the likelihood of desired health outcomes and are consistent with current professional knowledge. The American Medical Association describes high-quality care as that which consistently contributes to the improvement or maintenance of quality and/or duration of life. Conceptually, the elements of quality have been divided into structure, process, and outcome.

Appropriateness of Care
Quality of health care can be assessed in terms of appropriateness and necessity. Population-based measures of appropriateness are inversely proportional to how much health care is underused, overused, or misused based on reference criteria. Inappropriate care has been documented in substantial proportions of patients treated for a wide variety of conditions. The Institute of Medicine conducted a systematic search of the scientific literature from 1987 through July 1998 for qualityof- care studies and found, with few exceptions, large gaps between ideal care and the actual care patients received. The RAND Corporation found substantial deficits in the quality of care for 30 acute and chronic conditions for adults living in 12 metropolitan areas in the United States. Although these reports are disquieting, the consistency of negative reports suggests that the methods of measuring appropriateness of care may in fact be biased. A misclassification bias could explain why the vast majority of studies describe inappropriate care. The validity of the appropriateness methodologies will be challengeable, at least until the sensitivity and specificity of the tests themselves can be better established.

The Value of Medical Care
The growth of medical technologies and the rising cost of medical care have made the economic value of health care a more visible component of quality. Because price competition inhealth care is a much stronger force than quality competition, the purchasers of health care have begun to judge quality in terms of its value using tools like cost-effectiveness and cost-minimalization analysis.

The Variation Phenomenon

HISTORICAL PERSPECTIVE
In the 1960s, the National Halothane Study was conducted to determine if halothane caused fatal damage to the liver. The study was large, involving more than 856,000 patients. Although the primary results showed conclusively that halothane was not associated with increased risk of hepatic necrosis, the data also showed large differences in the surgical death rate among participating hospitals (i.e., a 24-fold range in mortality rates). Even after controlling for potential confounding factors, the excessive death rate in some hospitals translated to more than 300,000 excessive deaths annually in the United States. Follow up studies within the decade confirmed that significant variations in hospital mortality did exist and were independent of differences in patient mix. These striking disparities in outcomes raised serious questions about how physicians practiced medicine and whether variations in outcome were due to differences in quality of care. In the early 1970s, clinical epidemiologists presented data showing substantial geographic variation in the delivery of health care. These findings were attributed to irrational decision-making in the setting of clinical uncertainty. Over the next 30 years, the variation phenomenon was confirmed repeatedly in dozens of clinical settings.

Physicians show important and often dramatic differences in the use of medical resources, hospital beds, surgery, diagnostic tests, and medical therapies. The variation phenomenon is so robust and consistently documented that it may be one of the most universal characteristics of modern medicine. It has been shown conclusively that the differences in practice patterns cannot be explained by undetected case mix, inadequacies of data analysis, confounding factors or technical errors of study design. The variation phenomenon also is not the result of a small number of physicians.

Variation studies in the United States have had to take into account a reimbursement system that for decades tended to financially reward the delivery of more care rather than less. Variation in hospital admission rates and physician visits have been positively correlated with availability of beds and supply of physicians. Differences in supply of services can account for some variation in use, but other unknown factors also play an important role. Substantial variations in the rate of hospitalization in the Department of Veteran Affairs (VA) health care system, where physicians are salaried, indicates that factors other than economic are involved.

Studies documenting the wide variation in the delivery of care were not uniformly viewed as a quality of care issue, but as epidemiologic investigations into clinical outcomes matured, the implications of variation studies became less ambiguous. Though the reasons for differences in clinical outcome after adjustment for disease severity cannot be fully explained, a substantial body of data now supports an association of improved clinical outcome with increased patient volume. This association has been documented for hospitals and for physicians and is strongest for high-risk and highly technical procedures. The Institute of Medicine conducted a systematic review of the literature on the volumeoutcome relationship and found better outcomes with higher volume in 77 percent of studies of physician patient volume. In none of the studies was a negative effect of volume observed. None of those studies involved eye care.

VARIATION IN CARE OF ADULT CATARACT
Ophthalmologists show substantial differences in how they care for patients with adult cataract. There are significant variations in the use of preoperative tests, intraoperative technique, and methods of postoperative follow-up. The most comprehensive review of this material is found in the Guideline for Adult Cataract published by the Agency for Health Care Policy and Research (see Adult Cataract Guideline section). Geographic variation in the rate of cataract surgery is relatively small compared to other commonly performed surgeries.

Javitt et al used a cross-sectional, population-based approach to study the variation of cataract surgery among Medicare beneficiaries 65 years of age and older. They found an annual mean rate of 25.4 surgeries per 1,000 persons 65 years of age or older (SD = 6.2) and an association between higher rate of cataract surgery and female sex, more southerly latitude, higher allowed charge for surgery, and higher concentration of optometrists per Medicare beneficiary. There was no significant association between increased likelihood of cataract surgery and concentration of ophthalmologists, but a second epidemiological model they tested showed greater likelihood of surgery associated with white race and increased mean income.

Although there are marked differences in preoperative evaluation and surgical technique, clinical outcome after cataract extraction is generally excellent in eyes without co-morbidities.

Schein and colleagues found no difference in visual acuity outcome or occurrence of postoperative adverse events, other than rate of posterior capsular opacification, between phacoemulsification versus extracapsular cataract extraction. Unlike many technical procedures, clinical outcome did not vary according to annual volume of cataract surgery. In a meta-analysis of 90 studies on cataract extraction, summary statistics showed that excellent results were achieved regardless of the extraction technique used. The consistently good clinical outcomes following cataract surgery have made it difficult to substantiate claims that one management strategy or variation in technique is superior to another, particularly given the generally poor research methodologies used in studies reported in the literature (see Guidelines section).

Snellingen and associates reviewed the Cochrane Controlled Trials Register for randomized controlled trials evaluating surgical treatment of age-related cataract (last update February 2002). They identified six trials that randomized a total of 7,828 patients with cataract. In general, the outcomes in these studies were very good, with one trial conducted in the United Kingdom that found better visual outcome with phacoemulsification surgery than extracapsular surgery. The increased proportion of patients having phacoemulsification extraction that achieved a best corrected vision of 6/9 approached a statistically significance difference (relative risk 95% confidence interval = 0.991.14) The reviewers questioned the generalizability of the results from this twocenter study, however.

The variation phenomenon in cataract surgery remains an important health care issue despite consistently good outcomes because surgery costs the Medicare program more than US$ 3.4 billion annually and because the vast number of cases are discretionary procedures. The cost effectiveness of cataract surgery will demand greater scrutiny as the equivalency of surgical techniques are established. Goldzweig and associates reported significantly different rates of cataract extraction in a traditional fee-for-service setting compared to a prepaid setting. The discrepancy in care raises questions of whether surgery in the fee-for-service system is overused or in the prepaid system is underused. These findings are compounded by the difficulty in determining the clinical necessity of cataract surgery after it has been performed. An independent chart review of the preoperative history and ocular examination at ten academic centers showed that medical documentation was inadequate for assessing functional impairment in one quarter of cases. A specific deficit in visual function that could have justified cataract surgery was not found in 40% of charts reviewed.

Tobacman and associates assessed the appropriateness of cataract surgery at 10 academic medical centers and found a low percentage of surgeries performed for inappropriate reasons (range: 04%). Justification could not be determined (i.e., classified uncertain) in 114%. The wide range of inappropriate and uncertain cases in this study can be extrapolated to a large number of unnecessary cataract surgeries in the United States given the large number of procedures performed annually. It is unclear if the results from academic medical centers are generalizable to private practice.

Practice Guidelines
A practice guideline is a systematically developed document to assist practitioners and patients in making decisions about appropriate health care for a specific clinical condition. Related terms such as practice parameters, clinical pathways, and practice standards are often used interchangeably. The AMA uses guidelines to describe recommendations for a particular management strategy and practice parameter as an inclusional term for an informational guide that assists physicians in clinical decisionmaking. The implied distinction between parameter (i.e., a reference) and guideline (i.e., a standard) is not consistently observed in the literature. Any semantic distinction may have greater medicolegal than clinical importance.

Practice guidelines became commonplace in all fields of medicine and surgery during the 1990s. From 1989 to 2000, the number of practice parameters listed in the AMAs Clinical Practice Guideline Directory grew from 700 to 2,000.

BACKGROUND
Practice guidelines are a logical response to unwanted variation in clinical care, but they existed long before the variation phenomenon was recognized as a problem. One of the first widely used practice guidelines was created in 1938 by the American Academy of Pediatrics dealing with immunizations for children. By summarizing vast amounts of information into a usable format, early guidelines were viewed favorably by many practitioners. The development of guidelines has been typically under the purview of speciality groups.

In 1989, the federal government mandated the Agency for Health Care Policy and Research (AHCPR) to develop and disseminate practice guidelines to supplement efforts of physicians and otherhealth care organizations. The AHCPR (now the Agency for Healthcare Research and Quality, AHRQ) was created to enhance the quality, appropriateness and effectiveness of health care.

The AHCPR spearheaded an ambitious guideline development program that resulted in nearly 20 guidelines covering a variety of clinical disorders including adult cataract (see below). This program was eventually phased out and replaced with Evidence-Base Practice Centers. These Centers are joint ventures between government and private-sector groups with experience in the synthesis of scientific evidence. The expansion and complexity of medical technology and changes in the medical marketplace are two reasons for the proliferation of clinical guidelines over the last 15 years. The AHRQ joined forces with the AMA and the American Association of Health Plans in the 1990s for a National Guideline Clearinghouse.

The Clearinghouse became operational in 1999 as a repository for evidence-based practice guidelines.114 Criteria for inclusion into the Clearinghouse are strict. Guidelines must document that recommendations are a synthesis of evidence-based knowledge. As of December 2002, two adult cataract guidelines from professional organizations in North America have been accepted by the Clearinghouse: the AAO and the American Optometric Association (verified January 3, 2003: www.guideline.gov/index/search: cataract).

GUIDELINE DEVELOPMENT
Considerable effort has been put forth to develop and implement practice guidelines in order to standardize care and improve its quality. Methods of development, however, are neither uniform nor of consistent quality. Specific methods have been divided into four categories: informal consensus, formal consensus, evidence-based guidelines, and explicit guidelines. The oldest process is informal consensus which offers recommendations with little documentation on how they were developed. In 1977, the National Institutes of Health Consensus Development Program attempted to improve the process by implementing more formal discussion on evidence. The RAND Corporation several years later introduced the Delphi technique, which further formalized the process of weighing expert opinion with a nine-point scoring system for rating the appropriateness of given procedures. Although Delphi scores reflect the experts overall impression of a procedure, they are not a measure of the strength of evidence supporting effectiveness or appropriateness. Evidence-based guidelines measure the strength and validity of individual studies based on their methodological rigor with randomized clinical trials given the greatest weight. A number of organizations have published grading systems for strength of evidence. Explicit guidelines are the most comprehensive form of analysis. They factor into the final recommendation probability estimates of outcome, patient preferences and data from cost-effectiveness studies.

QUALITY OF GUIDELINES
The AMA, the American College of Physicians, the Canadian Medical Association, and the AHCPR have published criteria for evaluating the quality of guidelines. When carefully examined, published guidelines often do not meet the basic standards established by these organization. In a structured review of 279 practice guidelines published in peer-reviewed journals from 1985 to 1997, the overall adherence to standards was poor. Areas of greatest weakness were in the identification, evaluation and synthesis of scientific evidence. Guidelines are time consuming and costly to develop and once published may have short life spans due to the pace of scientific developments. Standardized assessment of 17 current practice guidelines published by AHRQ found about half were outdated in 6 years. The authors of the AHRQ review concluded that guidelines, in general, should be reassessed for validity every 3 years.

EFFECTIVENESS OF GUIDELINES
A systematic review of the effects of guidelines showed that they improve processes and outcomes modestly. In general, physicians consider guidelines to be good educational tools and, if used, are likely to improve quality of care. More than half of 286 general practitioners in Australia rated guidelines extremely or very useful. More than 80% of pediatricians surveyed by the American Academy of Pediatrics found guidelines helpful or extremely helpful. On the other hand, just less than 40% of primary care physicians in Canada reported changing practice behavior because of guidelines. Less than one-third of New York family practitioners, however, felt that guidelines altered their practices. Simply developing and disseminating practice guidelines, however, has minimal effect on changing practice behavior. The effectiveness of local implementation of nationally produced clinical guidelines are unclear. Cabana et al performed a systematic review of potential barriers to physician adherence to practice guidelines. The most common reasons for failure to use guidelines among the 76 articles analyzed were lack of awareness, disagreement, self-efficacy, outcome expectancy, and personal inertia. This range of barriers indicates that the overall issue of effective implementation is complex. The authors concluded that improving physician guideline adherence will likely require several strategies.

AUDIT AND FEEDBACK
Audit and feedback is one strategy that could enhance compliance with guidelines. In theory, a nonpunitive system that monitors physicians compliance with guidelines and provides constructive feedback might positively effect physician behavior. Foy and associates studied the attributes of clinical practice recommendations formulated from audits and how they influenced clinical behavior. The authors found that behavior changes varied according to whether the recommendations were compatible with clinician values. Although recommendations viewed as incompatible with clinician values were associated with lower compliance rates, they were nevertheless independently associated with a positivechange in practice behavior.

The effectiveness of audit and feedback to change clinical behavior was reviewed by Thomson OBrien and associates. They conducted a structured literature review of clinical trials of the audit and feedback method through June 1997. The quality of most published reports (37 studies) was inadequate for complete analysis. Many of the studies failed to identify the impact of the intervention on clinically important end points. The authors concluded that audit and feedback can sometimes be effective in improving the delivery of health care, but the magnitude of effect is usually small. Audit and feedback appears to be most effective when it compliments other quality improvement methodologies.

ADULT CATARACT GUIDELINE
Practice guidelines relevant to ophthalmology come from several sources including the American Academy of Ophthalmology (Preferred Practice Patterns), Agency for Health Care Policy and Research (AHCPR), and insurance and managed care organizations. Specific review of the content of practice guidelines for cataract surgery is not the intent of this review, but valuable lessons on the purport of guidelines in general can be gained by recounting the history of the development of the AHCPR guideline for adult cataract.

Historical Perspective
The AHCPR appointed a multidisciplinary panel of experts and other professionals to develop guidelines for the management of adult cataracts in 1990. The process for development was specified by the AHCPR and required an explicit methodological approach. The panel reviewed more than 8,000 articles related to cataract surgery and found less than 4% met criteria for inclusion. There was a paucity of scientifically sound studies despite the large database in peer-reviewed journals. Because many of the included articles were methodologically weak owing to flaws in experimental design, it was unlikely that strong evidence-based guidelines could be formulated. After a comprehensive examination of the published literature was complete, two open forums were held to solicit comments. The AHCPR panel wrote the guideline by consensus opinion. The guideline represented 2 years of work. When completed, the results were published in a 226-page softbound book that included a 25-page bibliography, four-page glossary, seven attachments related to testing visual function and anesthesia, biosketches on major contributors, and 133 pages summarizing the evidence-based literature on the prevention of cataracts, pathways to care, pre- and postoperative care, and technical aspects of treatment.

Before the guidelines were published, however, the integrity and professional competence of panel members were questioned in tabloid newspapers. The intent of these attacks, according to the chairman of the committee, was to destroy the panels credibility and prevent publication of the guideline. One reputable reviewer concluded that the cataract guideline met established criteria of validity, reliability, clinical applicability, clarity and multidisciplinary involvement. The guideline, however, received considerable negative criticism including failure to review relevant literature, over reliance on Snellen acuity, and lack of input from high-volume cataract surgeons. The guideline was also criticized because it did not approve the practice of screening for visually asymptomatic cataracts. The American Academy of Ophthalmology endorsed the guideline at the time of its publication, but the American Society of Cataract and Refractive Surgery did not. The American College of Eye Surgeons, the Outpatient Ophthalmic Surgery Society, the Society for Excellence in Eyecare, and the Society for Geriatric Ophthalmology united to develop their own guideline for the treatment of cataract.

In 1996, a white paper on cataract surgery was developed jointly by the American Academy of Ophthalmology and the American Society of Cataract and Refractive Surgery to help span the perceived divide between the AHCPR guidelines and recent knowledge about the practice of cataract surgery. The white paper agreed with the conclusion of the AHCPR panel that there are many areas in which insufficient data exist to make strong evidence-based recommendations. The latest revision of the Preferred Practice Pattern on cataract was September 2001, and is the only non-optometric practice guideline on adult cataract from North America currently listed in the National Guideline Clearinghouse. Of the 33 level A benchmarks (i.e., most important) for cataract evaluation in the AAO Preferred Practice Patterns, 29 (89%) are based on a consensus of expert opinion in the absence of strong or substantial scientific evidence.

COMPLIANCE WITH OPHTHALMIC GUIDELINES
There has been no scientifically designed study to determine how well ophthalmologists adhere to voluntary guidelines. The 1991 AMAs Socioeconomic Monitoring System core survey showed that 75.1% of responding ophthalmologists were aware of practice guidelines and 68.3% used them. There are no studies documenting whether guidelines have any effect on the delivery of eye care.

In a national study of 30 acute and chronic conditions, McGlynn and associates found substantial variation in the quality of delivered health care based on how well physicians adhered to recommended care. Among the 30 different medical conditions studied, adherence to recommended standards was the highest for senile cataract (78.7%; 95% CI: 73.384.2%). This good measure of compliance likely reflects the relatively universal confidence ophthalmologists have in cataract surgery for the treatment of senile cataract.

CRITIQUE OF GUIDELINES
Critics argue that guidelines codify medical practice, stifle creative approaches to patient care and create pathways for the enforcement of medical decision-making. The issues surrounding the use of guidelines in a pluralistic medical system like that in the United States are more complex than systems controlled by one administrative agency. Supporters contend that properly developed guidelines should reduce the incidence of inappropriate care, but only if all interested parties share responsibility for their research and implementation. The time and cost of developing practice guidelines is great; updates are needed more frequently as the rate of technologic development accelerates. Because many authors of practice guidelines have some form of affiliation with private industry, concern over conflict of interest exists. In one survey, 87% of guideline authors had affiliations with pharmaceutical companies including 57% receiving financial support for research and 38% having had served as an employee. Despite these conflicts of interest, specific declarations of industrial affiliation from these authors were found in only 2 of 70 of their published guidelines. There has been limited experience in determining the impact of practice guidelines on liability litigation. The courts appear to allow guidelines into evidence as standard of care, but they are usually not treated as the sole determinant of that standard.

There has been limited study on the impact of guidelines on cataract surgery. Escarce used Medicare physician claims data and a mathematical model determine the impact of practice guidelines on the rate of cataract surgery. According to this model, eliminating so-called practice style as a factor in decision-making through guidelines would reduce variation in cataract surgery rate by a small amount.

Physician Profiling
The public distribution of health care information care can be traced to Florence Nightingale, who urged the publication of mortality rates of London hospitals. Public and commercial disclosure of indicators of health care quality has more recently been linked to the rise of managed care and the disappearance of traditional indemnity insurance. Among other quality-of-care functions, performancebased assessments (e.g., performance reports, report cards, performance profiling, physician profiling) help purchasers select the greatest value for their investment.

CREATION OF PROFILES
Performance reports vary in design. Typically, information on hospitals or physicians is extracted from local, national, or proprietary databases for comparison with normative or community standards. Performance in such cases could be based on one or more of a variety of indicators, including utilization of resources, process of care, clinical outcome, or cost of care.

PUBLIC DISCLOSURE
Public disclosure has been a contentious issue in the quality-of-caremovement andis center stage in the debate over profiles. Physicians and laypersons have differing opinions on how so-called quality assurance reports should be used to improve health care. In a survey dealing with medical error, 86% of physicians believed that reports should be kept confidential where as 62% of laypersons favored public release. Laypersons believe that accountability is increased with the transparency of reporting, whereas physicians think that openness among colleagues is improved when reports are kept confidential. The divergence in beliefs of doctors and laypersons will play itself out as performance profiles continue to be used in the future.

EFFECTIVENESS
The extent to which physician profiling can effect change in practice behavior and resource utilization is important information for third party payers to have. A meta-analysis of studies of physician profiling showed a small but statistically significant reduction in cost outlay.

Marshall and colleagues performed a literature search of public release of performance data for evidence of its impact on medical care. From January 1986 through October 1999, seven United States reporting systems had been the subject of 21 peerreviewed evaluations, most of which were descriptive and observational. None dealt with eye care. Only three studies attempted to address the most critical question of how public disclosure influences outcomes of care. All three studies dealt with cardiovascular surgery and reported improvement in clinical outcome (see Lessons from Cardiac Surgery section). How public disclosed data will be used by the public, physicians, and purchasers of health care are less clear from these studies, as is the overall impact on cost of medical care.

Lessons from Cardiac Surgery
Performance profiles have made limited inroads in ophthalmology, but use is likely to increase because of their appeal to managed care organizations and the purchasers of health care. In the late 1980s, the New York Department of Health took action to reduce mortality after coronary-artery bypass grafting (CABG) by creating a registry to track the outcome of cardiac surgery. The experience of cardiac surgeons in New York with profiling is worth reviewing briefly because of its relevance to other fields of surgery.

In 1989, the New York Department of Health created a registry to collect clinical data on all patients having cardiac surgery in the state. The objective of this process was to provide feedback to both hospital and surgeon that would be helpful in improving quality of care and in reducing mortality related to surgery. Public health officials used established statistical methods to analyze postoperative mortality and pertinent risk factors. In 1990, the department released the 1989 crude and risk-adjusted mortality rates and volume of CABG procedures for New York hospitals to the public. There was considerable variation in risk-adjusted hospital mortality rates. The release of hospital-specific data, however, led to an inevitable demand for physician-specific rates. When the Department of Health refused to voluntarily release this information, the newspaper, Newsday, sued the department for public disclosure. The Health Department eventually lost the suit and the newspaper published mortality rates for individual surgeons in December 1991. The Cardiac Advisory Committee recommended to the Health Department that hospitals submit data making it impossible to track surgeons in the future, but that advice was not followed.

During this time, specific steps were taken to reduce mortality rates in hospitals with high rates. From 1989 to the end of 1992, there was a 41% decline is risk-adjusted operative mortality after CABG in the state of New York. A thorough description of corrective activities has been published. It is noteworthy that low-volume surgeons, many of whom had consistently high risk-adjusted mortality rates (four times the statewide average), were a focus of the states quality improvement initiative. By 1992, many low-volume surgeons had stopped performing surgery.

Performance report cards place additional pressure on participants to perform well. During the New York Health Department trial, on-site investigators discovered errors in coding of cardiac risk factors once the mortality rates were made public. The inflation of preoperative risk factors that were found would have resulted in more favorable surgical ratings had they not been detected by the oversight body.

Performance disclosure in cardiovascular surgery has reduced postoperative mortality. Proponents of performance reports like the one developed in New York believe profiling improves care by effectively motivating providers with achievable benchmarks and by removing low-quality providers. Believing that public disclosure empowers consumers and purchasers of health care, some states have mandated report cards. The Pennsylvania Consumer Guide to Coronary Artery Bypass Graft Surgery, for example, reflects the marketplace appeal of profiling. The Pennsylvania guide publishes a statewide list of surgeon-specific and hospital-specific mortality rates each year.

Performance Profiles in Cataract Surgery
There have been no mandatory public disclosures imposed on cataract surgeons. The AAO initiated a national eye care outcome network (NEON) to assess changes in practice patterns and clinical outcomes of cataract surgery. The NEON functions as a performance-based assessment, but enrollment was voluntary and physician profiles remained anonymous. Physician-specific data were reported only to the participating ophthalmologist. The registry opened in January 1996 for a fee of US$ 750.00 (fee later reduced). An initial 2-year assessment report was published in Ophthalmology. Thorough preoperative, operative, and postoperative patient data were collected and included both subjective and objected measures of outcome. A total of 7,626 patients were enrolled and 3,342 had complete data forms returned (44%) during the first 2 years. Only 249 ophthalmologists (less than 5% of AAO members) participated. The overall clinical outcomes were good, with 95% of patients satisfied with the results of surgery.

Although the logistics of providing feedback to eye surgeons on a national level were successful, there were a number of problems with NEON. First, it was not possible to draw meaningful conclusions regarding practice patterns because the number of physicians enrolled was small and probably not representative of all eye surgeons. Second, a large proportion of incomplete data sets occurred, which increases the likelihood that outcome results are biased. Even though complications rates reported to NEON were similar to rates reported in the literature, a mechanism to audit charts would be required to ensure full andaccurate reporting. Informal feedback from participates revealed that surgeons thought NEON useful for marketing, as outcome data for contracting purposes, and to fulfill quality improvement requirements. In March 2001,NEON was terminated because of a lack of participation and because of demand for this information from third parties. The program demonstrated that large volumes of individual patient data could be managed on a national level, but the project had contradictory goals that made its success unlikely. NEON did not have a mechanism to verify the accuracy of input data so the validity of the results remain in question.

Critique of Physician Profiles
The demand for involuntary profiling will continue, particularly from the purchasers of health care, regulatory agencies, and the public, despite a variety of objections. The reaction to physician profiles have been mixed and often polarized. Considering the controversial nature of this initiative, there have been few studies of its effectiveness in improving outcome and its impact on the commercial aspects of medical care. On one hand, there is some hesitancy for physicians to challenge the legitimacy of public disclosure in a society that values freedom of information and informed decisionmaking. The potential to misinterpret risk-adjusted profiled data by patients who may want just a simple ranking of the best doctors has been an argument against public release. Others claim that the statistical methodology for report cards is flawed and cannot justify the degree of accuracy assumed by the public. The claim that profiled physicians will avoid high-risk cases in order to improve their scores is plausible but still unproven. Data from the New York cardiac surgery registry may in fact refute the charge of high-risk avoidance. The ability to game the system and improve profiles by avoiding high-risk patients, however, has been demonstrated theoretically with diabetic care. Commercial or governmental organizations that are primarily concerned with resource utilization may not be willing to invest in a system of data collection and analysis capable of adjusting for differences in severity of illness.

Summary and Conclusions
Practice guidelines and physician profiling are intended to improve health care by reducing unwanted variation in the delivery and outcome of medical care. They differ fundamentally by the roles physicians play in each process. Under ideal circumstances, practice guidelines are physician-driven and based on analysis of evidence-based data. Physician profiling, by contrast, is an extrinsically driven process in which physicians have minimal or limited control.

The value of practice guidelines to close the gap between actual care and ideal care depends to a considerable extent on personal perspective. There have been a limited number of scientific studies dealing with the effect of clinical guidelines. Results have been mixed. Guidelines have been modestly successful in altering physician behavior at most, but because guidelines combine quality of care objectives with many business-related objectives (such as cost containment) they will likely play an increasingly prominent role in medical practice in the future.

Advocates of physician profiling attribute its effectiveness to accountability and market forces that reward high quality. Voluntary profiling networks, such as NEON, tend to collect biased data and have limited utility in changing physician behavior. Involuntary profiling, however, can promote change in clinical care and improve outcome.

The surgical management of cataracts is highly successful and shows little important variation in clinical outcome despite considerable variation in the delivery of care. Cataract surgery will continue to interest policy makers because of the cost of performing large numbers of cases each year. Clinical guidelines and physician profiles are more likely to be employed to reduce perceived overuse of cataract surgery than to correct for underuse. Economic forces will continue to play a critical role in developing health policy for what is viewed as discretionary medical care.

Critical Overview
The variation in the practice of medicine has been a cause celebre for quality of care advocates. The modest success of practice guidelines in reducing variation can also be viewed as its equivalent failureattributable to both cultural and economic barriers within medicine. Most important among these barriers are a lack of understanding of evidence-based medicine and the fear that guidelines will be used to deny claims for reimbursements and as evidence in malpractice litigation. These fears, plus the paucity of good clinical research in many areas of medicine, can result in incomplete and watered down practice guidelines.

The debate over whether to approach quality improvement by eliminating bad apples or fixing bad systems is ongoing and is intimately linked to methods to minimize practice variation. The traditional approach to name, blame, and punish those individuals whose performance is substandard has a logical appeal and also fuels the US tort system. This approach, however, overlooks mounting evidence that poor systems cause most errors. Even supporters of the quality improvement initiative have found the successful enactment of meaningful methodologies for hospital-based care challenging, but eye care, which is almost entirely out-patient and decentralized, presents even more formibable obstacles. Formulas and strategies for achieving better health care are plentiful and tend to reiterate several themes including greater use of information technology and creating better economic incentives for quality improvement. But the greatest barrier to successful implimentation of quality improvement initiatives (and perhaps the most underestimated) is convincing a critical mass of physicians and administrators that quality improvement must shift from blaming individuals for poor outcomes to improving the systems in which they work. Creating believers is not an easy task but begins with education at all levels of training and continues throughout clinical practice.

Methods of Literature Search
The history and development of practice guidelines and physician profiling was obtained from PubMed using search words practice guidelines, parameters, profiling, physician profiling, and report cards from 1966 through October 2002. Studies were limited to English and, for the most part, origin in North America. Relevant articles were also obtained from the bibliographies of retrieved articles and from the PubMed link related articles. Additional material came from 3 books and their bibliographies.

PubMed was used to identify articles specific to ophthalmology using terms eye disease, cataract, and ophthalmology, each cross-referenced with practice guidelines, practice parameters, profiling, professional profiling, physician profiling, appropriateness, quality assurance and quality of care. Two sources were used to research the variation phenomenon in cataract surgery: the adult cataract guidelines from the AHCPR1 and The Cochrane Library.

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