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An Agenda for Research in Ambulatory Patient Safety

Synthesis of a multidisciplinary conference to develop an agenda for research in ambulatory patient safety.

Executive Summary


This report of a multidisciplinary conference to develop an agenda for research in ambulatory patient safety is a synthesis of the presentations and discussions of conference participants, who included researchers, clinicians, ambulatory care administrators, purchasers, and policymakers (Appendix One). The conference was held on November 30 and December 1, 2000, after the publication of To Err is Human: Building a Safer Health System (Institute of Medicine 1999), and before publication of the later report from the Institute of Medicine (2001) titled Crossing the Chasm: A New Health System for the 21st Century. The work of many of the participants in the conference was cited in the two reports.

Conference participants reviewed the available evidence on the epidemiology of safety, risks, errors, and adverse events in ambulatory care and interventions to improve safety, then discussed directions for research to better understand the epidemiology and determinants of safety and injury in ambulatory care, and potential experiments and demonstrations to test approaches to reducing risks, errors, and injuries. The scope of the discussions ranged from "micro" topics, such as the value of automated physician order entry, to "macro" topics such as the infrastructure required to support highly reliable information and communication in ambulatory care, and the influence of payment systems on safety in ambulatory care.

The research agenda presented in this report, including the specific recommendations made, was extracted from these discussions, and the recommendations represent points of consensus as perceived by the authors of this synthesis. About nine months after the conference, each participant was provided a draft of this synthesis and asked to indicate his or her degree of agreement with each of the eleven recommendations. 46 of the 50 eligible participants responded. The results are consistent with representing the recommendations as reflecting a consensus of the participants. Recommendation 1 received the weakest support; Recommendation 6 and Recommendation 9 received the strongest support. The recommendations have not been formally endorsed by any individual participant.

This synthesis begins with a description of the conference and the methods used to organize the discussion of ambulatory patient safety. We describe the importance of the ambulatory sector, provide a review of the available literature on patient safety in ambulatory care, and summarize the main points from discussions among the conference participants. Recommendations from those discussions address what information should be sought and how to obtain it, and what interventions to improve safety should be tested and how effective interventions could be implemented. Because research and demonstrations will proceed within the context of law and regulation related to injury, error, and fault, and of culture and beliefs as well as scientific knowledge about the determinants of safety, the conference included a discussion of the environment for patient safety and its implications for research.

A summary conclusion from this conference, consistent with other reports on patient safety in ambulatory care, is that there is inadequate knowledge and understanding of the ambulatory care sector of the health care system in general, and of patient safety in ambulatory care in particular. The lack of in-depth knowledge severely limits our ability to understand the risks to patients, and to design and predict the effects of changes in ambulatory health care to improve care and outcomes, including patient safety.


The conference was organized around three sets of questions:

  • What do we know and what do we need to know about the epidemiology of patient safety in ambulatory care? What are the nature and scope of the risks to patient safety, and of adverse events? How will we get the data/knowledge we need?
  • What do we know and what do we need to know about strategies and methods to improve/ensure patient safety and to reduce adverse events? How will we get the data/knowledge we need?
  • What do we know and what do we need to know about effects of cultural, legislative, economic, and regulatory environments on patient safety and efforts to improve and ensure patient safety? How will we get the data/knowledge we need?

Each topic was introduced by a presentation designed to review much of what we know from the existing literature, and to set the stage for discussion. For each of the first two topics, six small groups of eight-nine persons then spent four hours in facilitated discussions. Each group was provided a number of specific questions (Appendix Two) that could be used to focus the discussions, but was encouraged to redefine the questions or focus on additional questions that were equally relevant. Each group was asked to search for consensus on what we know, and on research that would enable us to learn what we need to know.

Definitions and Assumptions

Discussions of patient safety and how to improve it are influenced by differences in assumptions about the nature of safety and risk, and the language used may reflect those assumptions. We did not attempt to define terms like "error" or "adverse event," but it was apparent that most participants shared an assumption that while some injuries in health care are the result of physicians, nurses, or other clinicians who are irresponsible, incompetent, impaired, or corrupt, most injuries and errors occur through more complex mechanisms that involve the processes and systems of care.

Errors and adverse events may occur because of individual actions or inaction due to deficiencies in an individual's knowledge, information, skills, judgment, and commitment. Where individuals err because of deficient knowledge, skill, judgment, or commitment, the individual should accept responsibility for the error and for its consequences. But responsibility for most errors and adverse outcomes is shared by the organizations, processes, and systems within which individuals provide care. Actions to reduce risks and errors will involve improvements on the part of the individual, in the processes that support the individual, and the systems within which the individual provides care. In ambulatory care, a substantial fraction of care depends on the patient and family as well as clinicians and organizations.

Patient care in hospitals is clinically and technologically complex, but clinicians are generally able to control what the patient does, and control the patient's environment, and there is a well developed supportive infrastructure for inpatient care. While most ambulatory care is less technologically complex than inpatient care, it is often more complex logistically, and the infrastructure frequently provides far less than optimal support for managing care. An episode of ambulatory care often requires communication and coordination among a number of clinicians, the patient, and family, and among several different sites—with many handoffs and transitions.

In ambulatory care, a substantial proportion of care depends not only on general and specialty physicians, but also on other health professionals, patients, and family members. Communications and coordination among these caregivers therefore may substantially influence outcomes of care.

The coordination and management of all these events is difficult for patients, and for physicians and their practices. It is complicated by physicians' acceptance of inadequate support systems. The organization of ambulatory health care—particularly of physician practices—reflects health care of a far simpler time, and has not kept up with the rapid development of medical science and of diagnostic and therapeutic capability, and with the increase in the clinical, technological, and logistical complexity of ambulatory care.

Most of the conference participants consider safety to be a part of quality, and believe that understanding risk and improving safety should take advantage of the conceptual framework and tools that have been developed in pursuit of improving quality. Consistent with the assumption that safety is best viewed in conjunction with quality, most conference participants include errors of omission within the rubric of patient safety. However, the focus on safety occurs within a different cultural environment, and is subject to stronger external influences such as tort liability.

Dimensions of Ambulatory Patient Safety

The Institute of Medicine's report (1999) estimated that 44,000 to 98,000 hospital patients die each year from avoidable medical error. Relatively little information has been collected on risks, errors, and their consequences in ambulatory care, yet much of the health care in the United States is delivered in ambulatory settings. The scope of ambulatory practice has steadily increased over the past several decades. Most medical and surgical procedures that were once provided only in hospitals are now routinely performed in ambulatory settings.

Ambulatory services are performed by a variety of health care providers and support personnel in a dizzying array of practice settings: physician offices, hospital emergency and outpatient departments, home health agencies, community health centers, urgent care centers, chemotherapy and radiation therapy centers, dialysis centers, diagnostic imaging centers, outpatient surgery centers, occupational health centers, mental health centers, women's health clinics, and other settings. The physician office practice is usually considered to be the "hub" of ambulatory care, and most primary care, provided mainly by family practice, general internist, pediatric, and obstetric/gynecology specialties, takes place in ambulatory care settings. Requirements and influences of managed care have made the job of the primary care provider increasingly demanding and complex.

The last twenty years have seen rapid growth in the volume and complexity of procedures provided in ambulatory settings, driven by improvements and innovation in technology, linked with changes in financing and reimbursement. Over 77 percent of all medical procedures are now performed in ambulatory settings, and improved anesthesia and pain management have expanded the scope of surgical procedures performed outside the hospital.

There are many types of health care personnel who are responsible for or involved in providing ambulatory patient care. In addition to the nearly 720,000 non-federal physicians, a large array of non-physician personnel provide a substantial proportion of patient care in ambulatory settings. Nurses, physician assistants, and other "mid-level practitioners and physician-extenders" are an increasingly important part of the health care delivery system, particularly in primary care. Advanced practice nurses, such as Nurse Practitioners and Certified Nurse Midwives, have substantial autonomy including the authority to prescribe medication.

The large numbers and variety of health care personnel, sites, and organizations imply a large number of transitions in patient care or "hand-offs" of responsibility for care, which are known to be points of increased risk for occurrence of error.

Ambulatory Patient Safety: What Do We Know?

Though there is little doubt that medical error and injury are substantial in ambulatory care, there has been little systematic research specifically aimed at patient safety questions in ambulatory care. A system this large and complex, with so many loosely linked components, makes it difficult to adequately frame the discussion of patient safety and identify the key questions that need to be addressed.

The principal sources of our knowledge of the epidemiology of patient safety in hospital care include the Harvard Medical Practice Study and several additional studies with similar methodology: the California study in the 1970s, and more recent studies in Utah and Colorado. A comprehensive study of risk and adverse events and their consequences in ambulatory care could be quite valuable, though a study of that magnitude would be challenging. There was consensus of participants that an analogous "Harvard study" for ambulatory health care would be very difficult to do well because of the variability and fragmentation of care, and the paucity or incompleteness of data sources such as the ambulatory medical record. A study would also be more difficult than in hospitals due to fear of liability and litigation. It was generally agreed that if such a study could be demonstrated to be feasible (through pilot studies, for example), it would be useful and valuable, but not essential to improving ambulatory patient safety.

Recommendation 1: AHRQ should support a feasibility study to:
  1. Identify appropriate methods to conduct a large-scale study of the epidemiology of safety/error in ambulatory care.
  2. Perform pilot testing of the methodologies.
  3. Estimate the projected value and costs of such a study.

Though there have been few large scale research initiatives in ambulatory safety, there have been focused studies on high-risk ambulatory care sites, procedures, processes, and populations, including ambulatory surgery centers and office based surgery, the elderly, endoscopy, and medication use. These studies provide windows into ambulatory patient safety and make it possible to begin to assemble a mosaic of its scope and structure. Some practice sites (e.g., small physician practices) and/or practice content (e.g., office surgery, cosmetic surgery) may be associated with increased risk, a higher rate of incidents, or greater average severity of consequences, and so may deserve higher priority for research.

Several influences that may reduce risk in inpatient care are less prevalent in ambulatory care. Most ambulatory sites are subject to less regulation, less peer interaction, and have less well developed policies and procedures (e.g., credentialing and privileging) to determine the training and experience required to perform surgery and invasive procedures, or to manage sedation and anesthesia. There are fewer checks on individuals with inadequate training and experience who wish to perform a high risk procedure such as liposuction. There are fewer standards and less regulation in outpatient settings, allowing greater variation in how well equipment is maintained (for example, monitoring devices), and in the education, training, and experience of personnel who use the equipment.

However, it is not clear whether the risks of invasive procedures are greater in physicians' offices than in hospitals. For example, malpractice data from the Physician's Insurance Association of America (PIAA) from 1995-97 show that hospital-performed liposuction yielded three times the total number of malpractice settlements than from office based procedures. The movement of increasingly complex procedures from inpatient to ambulatory settings may offer opportunities to improve patient safety. There is some evidence that surgical site infections are lower in ambulatory surgery settings than in hospitals. For some conditions and procedures—such as those that expose the patient to risks of surgical infections—the ambulatory setting may prove to be safer.

Some patient populations would be expected to be at greater risk in general and in ambulatory care in particular: persons with psychiatric disorders (including common mood disorder), comorbid illnesses, children and the elderly, the homeless, hearing impaired, those with language and culture differences, and those with reduced access for financial and other reasons. Errors in dosage can be very toxic to infants and children, and these errors are relatively common. Persons sixty-five and over are more likely to have several comorbid conditions and more severe illness, increasing the risk and consequences of adverse drug interactions and other forms of medical and surgical error. There is evidence that office based physicians not infrequently prescribe inappropriate medications for the elderly, and adverse drug events appear to be common in older outpatients who are taking multiple medications.

Sources of Data for Research on Ambulatory Safety

In the absence of a large body of scientifically rigorous studies, a practical strategy may be to exploit existing data and information from the area of risk management, particularly the experience of liability insurance companies, and from the case study experience of individual health care delivery organizations that have internalized functions of quality assurance and risk management. Information from such studies could be used to sketch an outline of the epidemiology of ambulatory patient risk and injury. Data and experience from investigations of medical liability claims and from risk management in provider organizations can also provide detailed information on selected kinds of incidents. The investigations that physician liability insurers conduct into the factors leading to occurrences and incidents should provide a rich source of information about connections in ambulatory care and the high-risk aspects of care. These elements can complement large epidemiological studies and smaller studies focused on important aspects of ambulatory care. Participants in the conference included persons from several large physician liability insurers and their risk management partners.

The aggregated experience of liability insurers' investigations can provide a starting point for constructing an epidemiological picture of ambulatory patient safety. For instance, several liability insurers have found that the largest single category of errors leading to claims and awards are delays and failures to diagnose (e.g., breast cancer), and the diagnostic process occurs largely in ambulatory care. However, the pattern of liability claims or settled cases would not be expected to provide a full and accurate picture of errors or adverse events—incidents leading to more serious injuries would be relatively over-represented, for example—so it would be important to understand how the rates and patterns represented in these data would differ from those found in a full and accurate epidemiological study.

Recommendation 2: Support research that examines and evaluates claim and incident data from liability insurers, and how the rates and patterns of incidents and injuries from these sources would be expected to differ from the "true" rates and patterns. Specific efforts could assess the value of case studies. Support evaluation of interventions by liability insurers that are designed to improve ambulatory patient safety, and identify those that are effective and should be widely disseminated.

Risk assessment and risk management activities designed to gather and analyze data in order to address specific problem areas have generated a substantial body of case studies that yields valuable information on the extent of individual patient safety problems and on their solution. Health care can also learn from experience in other industries, particularly aviation and nuclear power: hypotheses, approaches, and methods used to gain information, perform analyses, and implement measures to improve safety.

Recommendation 3: Support research that builds on experiences from risk management activities of liability insurers, provider organizations, and integrated healthcare systems, and from other industries to:
  1. Understand risks and injuries in ambulatory safety.
  2. Where to focus efforts to further understand risks and to reduce them.

Other Sources of Data on Ambulatory Safety

Providers, managed care organizations and pharmacy benefit management companies routinely collect large amounts of information. This information can be useful for identifying and quantifying the causes and effects of certain types of safety and quality problems. Such data may be useful for identifying prescriber adherence to best practices, patient adherence to prescribed therapy, and for connecting some processes and outcomes, especially when combined with medical event reporting systems specifically designed to address these problems.

The limitations of administrative systems are well documented, however. They may not reliably reflect some kinds of adverse events and errors, and the number and type of occurrences identified can vary according to source and method.

Recommendation 4: Support pilot studies to determine the potential of administrative data, alone and in combination with other data sources, for research in ambulatory patient safety. Identify appropriate methods for using these data, and barriers to their use.

Surveys of patients, physicians, nurses, and other staff can elicit information about actual and perceived risks, mistakes, injuries, and near misses. Surveys are useful to generate hypotheses for further investigation, and in principle, surveys can be used to generate estimates of population rates. Surveys must be carefully done to avoid low response rates and minimize bias, employing methods to obtain patient information that do not generate substantial concerns about liability and confidentiality, which are threats to unbiased responses.

Most methods of collecting data on medical errors and adverse events focus on providers and their medical records. Tracking or following patients through care can help us understand how ambulatory care works, highlight the potential for errors and adverse events associated with transitions and handoffs, and provide opportunities to understand how and where risks are generated by reliance on the patient to receive, understand, and act on medical information and recommendations.

Recommendation 5: Research should be conducted that assesses the perspectives of patients and families about ambulatory care, and characterizes the information they can provide about safety in ambulatory settings. Assess the reliability and validity of that information, identify methods that could ensure high rates of unbiased responses, and design potential studies that could yield population-based estimates of adverse events in ambulatory care and their causes.

Reporting Systems: Learning about Safety and Improving Accountability

To make the best use of resources for improving safety—attention, time, people, tools, money—enough trusted (valid, reliable) data must be available to prioritize these opportunities. Reporting systems for adverse events and near misses can provide these data. Although a number of reporting systems have been operational for many years, there are ways to improve upon them. The Institute of Medicine report To Err is Human (1999) recommended that each State should have a mandatory reporting system for medical errors. However, studies of existing State reporting systems—most limited to hospitals—show a great deal of variation in design and function. Only 15 States require mandatory reporting of adverse events from acute care and general hospitals, and they use a variety of definitions for reportable events. The protection of confidentiality also varies from State to State. State programs cited under-reporting and inadequate resources as the greatest areas of concern with reporting systems.

There is a lively debate underway about whether reporting should be voluntary or mandatory, or both, perhaps for different purposes. Architects of reporting systems must consider that, with few exceptions, accurate, in-depth reporting depends on voluntary behaviors on the part of reporters who cannot be effectively coerced. Coercion is likely to induce resistance behaviors with unintended consequences such as downcoding of events, suppression of sensitive data, and proforma activities that consume resources but do not lead to improvements. The relationship between reporting and liability will strongly influence the willingness of physicians and health care organizations to participate in a reporting system, whether voluntary or mandatory.

Voluntary reporting may work best for near misses and other threats to safety, where the reporter's level of fear is small compared to adverse events with significant injuries, which are more likely to lead to lawsuits and claims. An often-overlooked benefit of voluntary learning systems is the possibility of systematically identifying examples of excellence, such as recoveries from events that could have had serious adverse outcomes, and disseminating those findings as case studies and as validated clusters that can lead to best practices.

It may be that an effective mandatory reporting system is necessary to meet regulatory requirements, to support deemed accreditation programs, or to build public confidence. One approach to mandatory reporting would identify a group of "never events" that all stakeholders can agree should never happen and should be reported, such as those recently defined by the National Quality Forum (NQF). Though the 27 events identified by the NQF are defined for inpatient care, a number of them can relate indirectly to events in ambulatory care.

AHRQ has recently announced funding for a series of patient safety projects, including a number that are focused on medical event reporting and feedback. The results of these studies, combined with efforts by the NQF and experience with existing systems, will likely enable convergence on a number of standards. If done collaboratively, evaluation of existing reporting systems and design of new systems will build trust and confidence among those charged with strengthening accountability and those that deliver care.

Collecting data on near misses offers less potential for litigation than does data on adverse events with injury, and there is a unique opportunity to capture maps of recoveries when injury was avoided (How was the event cascade recognized and controlled before injury occurred, or was injury avoided due to chance?) and use that information to systematically improve systems design and training. The much larger number of near misses allows quantification and trending of types of events, and provides enough data to evaluate the effectiveness and power of interventions.

Reporting systems usually focus on information from clinicians, and traditional incident reporting systems have depended primarily on reports submitted by nurses. In addition to reporting by physicians, nurses, and other clinicians, information can also be gathered from patients, from clinical information systems, and from electronic as well as paper medical records. A number of studies focused on inpatient and outpatient adverse events show that the number and distribution of occurrences and incidents reported or identified will vary by the source and the methods used.

Participants in the conference generally agreed that a large scale epidemiological study of risks and adverse events in ambulatory care would be difficult to do. A robust and complete reporting system, which is in essence an observational study, may provide an alternative to large scale epidemiological studies, and could support improvement in the bargain. The two sources of data can be complementary, as trends and case studies from the reporting system can serve as data to stimulate hypothesis generation and controlled studies of systems interventions.

There is much to be learned from experiences in other industries that can help design safety reporting systems and initiatives to improve safety for health care. However, there are differences between health care and these industries that will require thoughtful translation of lessons learned from them to health care. A number of complex, hazardous industries have experience with safety reporting systems over the past 30-40 years. Several trends have been observed. First, there has been a shift from anonymous to confidential sources of data, to increase validity and scope of information about events. This has been enabled by evolved legal protections, as well as through devices such as obtaining confidential data within a short window of opportunity after the event and then stripping the data of identifiers. The objective is to learn about threats to safety, and some events may be so sensitive, induce guilt to such a degree, or have such significant consequences that operators might not communicate the needed data without the protection of anonymity. In some industries (e.g., commercial aviation), serious accidents may have become rare enough that near misses provide the best available data for learning and accountability.

Through many years of experience, the concept of "root cause" has evolved in these industries. The logic underlying root cause analysis is now complemented by a new model of disturbances in complex systems where many small, potentially inconsequential events may, if combined in the proper context, cause a disproportionately serious accident. While there are "upstream" factors leading to an incident ("latent factors"), the notion of root cause can create a false frame of reference that there are one or two ultimate, concrete causative agents or entities.

It will be necessary to provide "training" about what to report and how, and to structure the reporting vehicle to ask questions that elicit the information needed in the report. For instance, many clinicians may be much more aware of errors by individuals than of latent errors that are properties of processes and systems. They may not notice the latter, nor be able to report on them accurately.

Reporting must be linked to action to improving patient safety. If there is no link, clinicians (and patients) may feel little incentive and willingness to report—nothing constructive would be done with the information. If this logic holds, it may be best to organize reporting at a level where it can be acted upon to improve care and safety. Nested models may have advantages over an all-inclusive national reporting system. Local reporting with local feedback is most effective for leading to action, but aggregate data across many physicians, organizations, and locations is needed to identify larger patterns and to see infrequent occurrences. Local reporting could be organized according to particular hospitals, group practices, or physicians covered by a particular liability insurer, with those entities reporting up to the State or national level.

It is likely that many of the physician practices and other small organizations in ambulatory care will not have the expertise or capability to analyze their own data and understand its implications. Also, the time and effort to report errors and incidents will have to compete with all the other claims on the time of clinicians, administrators, and staff in ambulatory care. These capabilities might be provided by an entity to which the practice or other organization belongs and to which it reports, such as a large affiliated care system, or an accrediting program like those for ambulatory surgery centers. Such an arrangement would enable the larger entity to protect confidentiality, to put the data and experience of each small organization in the context of similar organizations, and to provide support for improving safety in both the organization reporting the incident and others with the risk of similar incidents. For smaller organizations, including most physician practices, it may be necessary to offer "turn key" programs that provide, in standardized form, the knowledge, tools, training, and support needed to succeed.

Accrediting organizations active in ambulatory care (the Accreditation Association for Ambulatory Health Care, the American Association for Accreditation of Ambulatory Surgery Facilities, the Institute for Medical Quality in California, the Joint Commission on Accreditation of Healthcare Organizations, and the National Committee for Quality Assurance) have or are planning to offer programs for reporting and for learning from and acting on reports. Accrediting agencies can establish standards for personnel, equipment, procedures, and processes (including documentation), for particular ambulatory care sites (e.g., ambulatory surgery centers) or particular activities and procedures (e.g., conscious sedation and anesthesia, office based surgery, tumescent liposuction).

Tradition and culture are powerful inertial forces, and consistent sustained pressure and resources need to be brought to bear to alter attitudes, behaviors, and values about reporting that cut across disciplines and hierarchies in healthcare organizations. Change itself can be difficult to initiate and sustain, but a number of programs and tools have become available to support change.

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Page last reviewed December 2001
Internet Citation: Introduction: An Agenda for Research in Ambulatory Patient Safety. December 2001. Agency for Healthcare Research and Quality, Rockville, MD.


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