Overconfidence as a cause of diagnostic error in medicine

Clinical reasoning in the real world is mediated by bounded rationality: implications for diagnostic clinical practice guidelines

BACKGROUND

Little is known about the reasoning mechanisms used by physicians in decision-making and how this compares to diagnostic clinical practice guidelines. We explored the clinical reasoning process in a real life environment.

METHOD

This is a qualitative study evaluating transcriptions of sixteen physicians' reasoning during appointments with patients, clinical discussions between specialists, and personal interviews with physicians affiliated to a hospital in Brazil.

RESULTS

FOUR MAIN THEMES WERE IDENTIFIED: simple and robust heuristics, extensive use of social environment rationality, attempts to prove diagnostic and therapeutic hypothesis while refuting potential contradictions using positive test strategy, and reaching the saturation point. Physicians constantly attempted to prove their initial hypothesis while trying to refute any contradictions. While social environment rationality was the main factor in the determination of all steps of the clinical reasoning process, factors such as referral letters and number of contradictions associated with the initial hypothesis had influence on physicians' confidence and determination of the threshold to reach a final decision.

DISCUSSION

Physicians rely on simple heuristics associated with environmental factors. This model allows for robustness, simplicity, and cognitive energy saving. Since this model does not fit into current diagnostic clinical practice guidelines, we make some propositions to help its integration.

Patient safety and acute care medicine: lessons for the future, insights from the past

This article is one of ten reviews selected from the Yearbook of Intensive Care and Emergency Medicine 2010 (Springer Verlag) and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/yearbook. Further information about the Yearbook of Intensive Care and Emergency Medicine is available from http://www.springer.com/series/2855.

Inferences of clinical diagnostic reasoning and diagnostic error

This paper discusses clinical diagnostic reasoning in terms of a pattern of If/then/Therefore reasoning driven by data gathering and the inference of abduction, as defined in the present paper, and the inferences of retroduction, deduction, and induction as defined by philosopher Charles Sanders Peirce. The complex inferential reasoning driving clinical diagnosis often takes place subconsciously and so rapidly that its nature remains largely hidden from the diagnostician. Nevertheless, we propose that raising such reasoning to the conscious level reveals not its basic pattern and basic inferences, it also reveals where errors can and do occur and how such errors might be reduced or even eliminated.

Pitfalls in the evaluation of shortness of breath

This article illustrates the challenges practitioners face evaluating shortness of breath, a common emergency department complaint. Through a series of patient encounters, pitfalls in the evaluation of shortness of breath are reviewed and discussed.

Diagnostic error and clinical reasoning

CONTEXT

There is a growing literature on diagnostic errors. The consensus of this literature is that most errors are cognitive and result from the application of one or more cognitive biases. Such biased reasoning is usually associated with 'System 1' (non-analytic, pattern recognition) thinking.

METHODS

We review this literature and bring in evidence from two other fields: research on clinical reasoning, and research in psychology on 'dual-process' models of thinking. We then synthesise the evidence from these fields exploring possible causes of error and potential solutions.

RESULTS

We identify that, in fact, there is very little evidence to associate diagnostic errors with System 1 (non-analytical) reasoning. By contrast, studies of dual processing show that experts are as likely to commit errors when they are attempting to be systematic and analytical. We then examine the effectiveness of various approaches to reducing errors. We point out that educational strategies aimed at explaining cognitive biases are unlikely to succeed because of limited transfer. Conversely, there is an accumulation of evidence that interventions directed at specifically encouraging both analytical and non-analytical reasoning have been shown to result in small, but consistent, improvements in accuracy.

CONCLUSIONS

Diagnostic errors are not simply a consequence of cognitive biases or over-reliance on one kind of thinking. They result from multiple causes and are associated with both analytical and non-analytical reasoning. Limited evidence suggests that strategies directed at encouraging both kinds of reasoning will lead to limited gains in accuracy.

Effect of nutritional support team restructuring on the use of parenteral nutrition

OBJECTIVE

The inappropriate use of parenteral nutrition (PN) continues to be a problem, despite several decades of efforts to improve the situation. We restructured our existing nutritional support team employing methods involving the institution's systems and individual physician interaction and education. Our aim was to study the effects of these changes on the use of PN in our institution.

METHODS

Records of all non-critically ill patients seen by our nutritional support team for PN during 2003-2004 (phase I, before restructuring) and 2005-2006 (phase II) were reviewed. Patients were classified under "appropriate," "inappropriate," and "marginal" categories based on published guidelines. During phase II, a new committee was formed, policies and procedures were updated, educational activities were increased, emphasis was placed on evidence-based guidelines, and periodic bedside rounds with the team physicians were initiated. Communication with referring physicians was improved.

RESULTS

Three hundred three of 335 patients in phase I and 271 of 333 patients in phase II were eligible for inclusion in analysis. Appropriate PN increased from 71.3% to 83.4%; inappropriate PN decreased from 16.5% to 8.9% (P = 0.002).

CONCLUSION

Restructuring of the nutritional support team improved the proper utilization of PN and decreased inappropriate use of PN in a public teaching hospital.

Next steps: envisioning a research agenda

The topic of diagnostic error is a relatively new one in the academic arena and lacks an organized research agenda. Participants at "Diagnostic Error in Medicine- 2008" formally considered this issue and provided initial suggestions. Recommendations were made to standardize taxonomies and definitions, especially in regard to what constitutes a delay in diagnosis. Error discovery needs emphasis, especially with autopsies becoming a rarity. Developing standardized tools to study diagnostic error in laboratory-like conditions was viewed as a top priority. Many issues were reviewed in regard to error generation (what conditions are error-prone, what is the role of the clinicians expertise, etc.), and error reduction. These included both system-level and cognitive interventions, with specific suggestions for each dimension.

Educational strategies to reduce diagnostic error: can you teach this stuff?

Diagnostic error typically involves both system-related and cognitive root causes. Educational interventions are proposed to address both of these dimensions: In regard to system-related origins, education should focus on communication skills, including handoffs. In regard to cognitive shortcomings, educators need to consider both normative approaches to decision making, as well as the 'flesh and blood' processes used by experienced clinicians. In the long term, the goal of education should be to promote expertise, based on the assumption that experts make the fewest mistakes. In the short term, education should emphasize the importance of reflective practice, and consider use of a checklist for diagnosis to improve reliability.

Clinical cognition and diagnostic error: applications of a dual process model of reasoning

Both systemic and individual factors contribute to missed or delayed diagnoses. Among the multiple factors that impact clinical performance of the individual, the caliber of cognition is perhaps the most relevant and deserves our attention and understanding. In the last few decades, cognitive psychologists have gained substantial insights into the processes that underlie cognition, and a new, universal model of reasoning and decision making has emerged, Dual Process Theory. The theory has immediate application to medical decision making and provides an overall schema for understanding the variety of theoretical approaches that have been taken in the past. The model has important practical applications for decision making across the multiple domains of healthcare, and may be used as a template for teaching decision theory, as well as a platform for future research. Importantly, specific operating characteristics of the model explain how diagnostic failure occurs.

Diagnostic error in medical education: where wrongs can make rights

This paper examines diagnostic error from an educational perspective. Rather than addressing the question of how educators in the health professions can help learners avoid error, however, the literature reviewed leads to the conclusion that educators should be working to induce error in learners, leading them to short term pain for long term gain. A variety of literatures are reviewed that suggest errors in performance are necessary pre-conditions for learning to occur such that an aversion to errors, while more comforting to the learner, is counter-productive. Similarly, research is reviewed that suggests strategies aimed at avoiding heuristic-driven diagnostic errors may successfully reduce those types of errors, but may do so at the expense of inducing errors of comprehensiveness. Taken together, the variety of studies contained suggest that diagnostic errors are often beneficial and that we as an educational community should strive to determine how to harness their pedagogical and diagnostic benefits rather than simply trying to eliminate mistakes entirely.

Dual processing and diagnostic errors

In this paper, I review evidence from two theories in psychology relevant to diagnosis and diagnostic errors. "Dual Process" theories of thinking, frequently mentioned with respect to diagnostic error, propose that categorization decisions can be made with either a fast, unconscious, contextual process called System 1 or a slow, analytical, conscious, and conceptual process, called System 2. Exemplar theories of categorization propose that many category decisions in everyday life are made by unconscious matching to a particular example in memory, and these remain available and retrievable individually. I then review studies of clinical reasoning based on these theories, and show that the two processes are equally effective; System 1, despite its reliance in idiosyncratic, individual experience, is no more prone to cognitive bias or diagnostic error than System 2. Further, I review evidence that instructions directed at encouraging the clinician to explicitly use both strategies can lead to consistent reduction in error rates.

A universal model of diagnostic reasoning

Clinical judgment is a critical aspect of physician performance in medicine. It is essential in the formulation of a diagnosis and key to the effective and safe management of patients. Yet, the overall diagnostic error rate remains unacceptably high. In more than four decades of research, a variety of approaches have been taken, but a consensus approach toward diagnostic decision making has not emerged. In the last 20 years, important gains have been made in psychological research on human judgment. Dual-process theory has emerged as the predominant approach, positing two systems of decision making, System 1 (heuristic, intuitive) and System 2 (systematic, analytical). The author proposes a schematic model that uses the theory to develop a universal approach toward clinical decision making. Properties of the model explain many of the observed characteristics of physicians' performance. Yet the author cautions that not all medical reasoning and decision making falls neatly into one or the other of the model's systems, even though they provide a basic framework incorporating the recognized diverse approaches. He also emphasizes the complexity of decision making in actual clinical situations and the urgent need for more research to help clinicians gain additional insight and understanding regarding their decision making.

Computer protocols: how to implement

Variation in clinical practice impedes control, is associated with unwanted and widespread error, and may preclude replicability. Methodologic replicability enhances our ability to detect signals of interest by both increasing the signal through consistent application of the intervention, and by reducing the obscuring effects of noise. Decision-support tools are intended to standardize some aspect of clinical care and thereby help lead to uniform implementation of clinical interventions. This is realized by explicit replicable computer protocols that can produce appropriate patient-specific decisions and introduce control of process into clinical care. Development of such protocols has required around-the-clock implementation for patient management because of the influence of patient history and previous patient states on the output of the computer protocol. Three successful computer protocols for management of blood glucose provide compelling examples. This clinician driven "bottom-up" approach complements the common information technology service driven "top-down" approach to clinical problems.

Design of a study on suboptimal cognitive acts in the diagnostic process, the effect on patient outcomes and the influence of workload, fatigue and experience of physician

BACKGROUND

Diagnostic error is an important error type since diagnostic adverse events are regularly judged as being preventable and the consequences are considered to be severe. Existing research often focuses on either diagnostic adverse events or on the errors in diagnostic reasoning. Whether and when an incorrect diagnostic process results in adverse outcomes has not been studied extensively. The present paper describes the design of a study that aims to study the relationship between a suboptimal diagnostic process and patient outcomes. In addition, the role of personal and circumstantial factors on the quality of the diagnostic process will be examined.

METHODS/DESIGN

The research questions were addressed using several data sources. First, the differential diagnosis was assessed concurrently to the diagnostic process. Second, the patient records of 248 patients suffering from shortness of breath were reviewed by expert internists in order to reveal suboptimal cognitive acts and (potential) consequences for the patient. The suboptimal cognitive acts were discussed with the treating physicians and classified with the taxonomy of unsafe acts. Third, workload, fatigue and work experience were measured during the physicians work. Workload and fatigue were measured during the physicians shift using the NASA tlx questionnaire on a handheld computer. Physicians participating in the study also answered questions about their work experience.

DISCUSSION

The design used in this study provides insight into the relationship between suboptimal cognitive acts in the diagnostic process and possible consequences for the patient. Suboptimal cognitive acts in the diagnostic process and its causes can be revealed. Additional measurements of workload, fatigue and experience allow examining the influence of these factors on the diagnostic process. In conclusion, the present design provides a method with which insights in weaknesses of the diagnostic process and the effect on patient outcomes can be studied and opportunities for improvement can be obtained.

Exploring the iceberg of errors in laboratory medicine

The last few decades have seen a significant decrease in the rates of analytical errors in clinical laboratories, and currently available evidence demonstrates that the pre- and post-analytical steps of the total testing process (TTP) are more error-prone than the analytical phase. In particular, most errors are identified in pre-pre-analytic and post-post analytic steps outside the walls of the laboratory, and beyond its control. However, in a patient-centered approach to the delivery of health care services, there is the need to investigate any possible defect in the total testing process that may have a negative impact on the patient. In fact, in the interests of patients, any direct or indirect negative consequence related to a laboratory test must be considered, irrespective of which step is involved and whether the error is caused by a laboratory professional (e.g., calibration or testing error) or by a non-laboratory operator (e.g., inappropriate test request, error in patient identification and/or blood collection). Data on diagnostic errors in primary care and in the emergency department setting demonstrate that inappropriate test requesting and incorrect interpretation account for a large percentage of total errors whatever the discipline involved, be it radiology, pathology or laboratory medicine. Patient misidentification and problems in communicating results, which affect the delivery of all diagnostic services, are widely recognized as the main goals for quality improvement. Therefore, some common problems affect diagnostic errors, although specific faults characterising errors in laboratory medicine should lead to preventive and corrective actions if evidence-based quality indicators are developed, implemented and monitored. The lesson we have learned is that each practice must examine its own total testing process to discover its weaknesses and identify appropriate remedies.