Mark L. Graber

Overconfidence as a Cause of Diagnostic Error in Medicine

The great majority of medical diagnoses are made using automatic, efficient cognitive processes, and these diagnoses are correct most of the time. This analytic review concerns the exceptions: the times when these cognitive processes fail and the final diagnosis is missed or wrong. We argue that physicians in general underappreciate the likelihood that their diagnoses are wrong and that this tendency to overconfidence is related to both intrinsic and systemically reinforced factors. We present a comprehensive review of the available literature and current thinking related to these issues. The review covers the incidence and impact of diagnostic error, data on physician overconfidence as a contributing cause of errors, strategies to improve the accuracy of diagnostic decision making, and recommendations for future research.

Cognitive interventions to reduce diagnostic error: a narrative review

Background Errors in clinical reasoning occur in most cases in which the diagnosis is missed, delayed or wrong. The goal of this review was to identify interventions that might reduce the likelihood of these cognitive errors. Design We searched PubMed and other medical and non-medical databases and identified additional literature through references from the initial data set and suggestions from subject matter experts. Articles were included if they either suggested a possible intervention or formally evaluated an intervention and excluded if they focused solely on improving diagnostic tests or provider satisfaction. Results We identified 141 articles for full review, 42 reporting tested interventions to reduce the likelihood of cognitive errors, 100 containing suggestions, and one article with both suggested and tested interventions. Articles were classified into three categories: (1) Interventions to improve knowledge and experience, such as simulation-based training, improved feedback and education focused on a single disease; (2) Interventions to improve clinical reasoning and decision-making skills, such as reflective practice and active metacognitive review; and (3) Interventions that provide cognitive ‘help’ that included use of electronic records and integrated decision support, informaticians and facilitating access to information, second opinions and specialists. Conclusions We identified a wide range of possible approaches to reduce cognitive errors in diagnosis. Not all the suggestions have been tested, and of those that have, the evaluations typically involved trainees in artificial settings, making it difficult to extrapolate the results to actual practice. Future progress in this area will require methodological refinements in outcome evaluation and rigorously evaluating interventions already suggested, many of which are well conceptualised and widely endorsed.

Diagnostic Errors in Medicine: A Case of Neglect

BACKGROUND Medical diagnoses that are wrong, missed, or delayed make up a large fraction of all medical errors and cause substantial suffering and injury. Compared with other types of medical error, however, diagnostic errors receive little attention-a major factor in perpetuating unacceptable rates of diagnostic error. Diagnostic errors are fundamentally obscure, health care organizations have not viewed them as a system problem, and physicians responsible for making medical decisions seldom perceive their own error rates as problematic. The safety of modem health care can be improved if these three issues are understood and addressed. SOLUTIONS Opportunities to improve the visibility of diagnostic errors are evident. Diagnostic error needs to be included in the normal spectrum of quality assurance surveillance and review. The system properties that contribute to diagnostic errors need to be systematically identified and addressed, including issues related to reliable diagnostic testing processes. Even for cases entirely dependent on the skill of the clinician for accurate diagnosis, health care organizations could minimize errors by using system-level interventions to aid the clinician, such as second readings of key diagnostic tests and providing resources for clinical decision support. Physicians need to improve their calibration by getting feedback on the diagnoses they make. Finally, clinicians need to learn about overconfidence and other innate cognitive tendencies that detract from optimal reasoning and learning. CONCLUSION Clinicians and their health care organizations need to take active steps to discover, analyze, and prevent diagnostic errors.

Performance of a Web-Based Clinical Diagnosis Support System for Internists

BACKGROUNDClinical decision support systems can improve medical diagnosis and reduce diagnostic errors. Older systems, however, were cumbersome to use and had limited success in identifying the correct diagnosis in complicated cases.OBJECTIVETo measure the sensitivity and speed of “Isabel” (Isabel Healthcare Inc., USA), a new web-based clinical decision support system designed to suggest the correct diagnosis in complex medical cases involving adults.METHODSWe tested 50 consecutive Internal Medicine case records published in the New England Journal of Medicine. We first either manually entered 3 to 6 key clinical findings from the case (recommended approach) or pasted in the entire case history. The investigator entering key words was aware of the correct diagnosis. We then determined how often the correct diagnosis was suggested in the list of 30 differential diagnoses generated by the clinical decision support system. We also evaluated the speed of data entry and results recovery.RESULTSThe clinical decision support system suggested the correct diagnosis in 48 of 50 cases (96%) with key findings entry, and in 37 of the 50 cases (74%) if the entire case history was pasted in. Pasting took seconds, manual entry less than a minute, and results were provided within 2–3 seconds with either approach.CONCLUSIONSThe Isabel clinical decision support system quickly suggested the correct diagnosis in almost all of these complex cases, particularly with key finding entry. The system performed well in this experimental setting and merits evaluation in more natural settings and clinical practice.

System-related interventions to reduce diagnostic errors: a narrative review

Background Diagnostic errors (missed, delayed or wrong diagnosis) have recently gained attention and are associated with significant preventable morbidity and mortality. The authors reviewed the recent literature and identified interventions that address system-related factors that contribute directly to diagnostic errors. Methods The authors conducted a comprehensive search using multiple search strategies. First, they performed a PubMed search to identify articles exclusively related to diagnostic error or delay published in English between 2000 and 2009. They then sought papers from references in the initial dataset, searches of additional databases, and subject matter experts. Articles were included if they formally evaluated an intervention to prevent or reduce diagnostic error; however, papers were also included if interventions were suggested and not tested to inform the state of the science on the subject. Interventions were characterised according to the step in the diagnostic process they targeted: patient–provider encounter; performance and interpretation of diagnostic tests; follow-up and tracking of diagnostic information; subspecialty and referral-related issues; and patient-specific care-seeking and adherence processes. Results 43 articles were identified for full review, of which six reported tested interventions and 37 contained suggestions for possible interventions. Empirical studies, although somewhat positive, were non-experimental or quasi-experimental and included a small number of clinicians or healthcare sites. Outcome measures in general were underdeveloped and varied markedly among studies, depending on the setting or step in the diagnostic process. Conclusions Despite a number of suggested interventions in the literature, few empirical studies in the past decade have tested interventions to reduce diagnostic errors. Advancing the science of diagnostic error prevention will require more robust study designs and rigorous definitions of diagnostic processes and outcomes to measure intervention effects.

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.

When diagnostic testing leads to harm: a new outcomes-based approach for laboratory medicine.

Many diagnostic errors are associated with laboratory testing, and many of these are preventable. However, a reduction in testing-related diagnostic errors (TDE) is hindered by the absence of a well-defined relationship between diagnostic harm and the testing process (whether from laboratory or non-laboratory sources) as well as by a lack of relevant measures for evaluation. The goal of this paper is to review current models that describe the testing process, and then propose a different approach to facilitate the reduction of diagnostic errors and harm related to diagnostic testing. We then demonstrate how this approach can be used to develop measures that may improve patient outcomes and guide future research to reduce TDE. Finally, we highlight the need for collaboration between clinicians and laboratory physicians and scientists to achieve these goals. Diagnoses typically result from the patient history and physical. However, diagnostic testing is often used to confirm initial impressions or rule out alternatives, and at least 10% of all diagnoses are not considered final until clinical laboratory testing is complete.1 ,2 This number most likely underestimates the actual impact of testing on diagnosis. In the emergency room, clinical laboratory testing is ordered in more than 41% of all visits.3 Family physicians order tests in 29% of all patient visits, and general internists, in 38% of visits.4 These percentages would be even higher if the calculations were based only on the 33.9% of primary care visits that involve a new complaint.5 Advances in technology have also contributed to the increased importance of laboratory tests. In the past, laboratory tests were used to identify organ and system dysfunctions or diseases. While this is still true, testing nowadays is used to diagnose disease subtypes, as occurs when pathology reports of cancer are accompanied by tumour-specific and patient-specific …

Improving Diagnosis in Health Care — The Next Imperative for Patient Safety

An IOM report highlights diagnostic errors as common patient-safety problems. Its recommendations address myriad system features and activities affecting diagnosis, acknowledging that many contributing factors are intricately related to health care delivery problems.

The patient is in: patient involvement strategies for diagnostic error mitigation

Although healthcare quality and patient safety have longstanding international attention, the target of reducing diagnostic errors has only recently gained prominence, even though numerous patients, families and professional caregivers have suffered from diagnostic mishaps for a long time. Similarly, patients have always been involved in their own care to some extent, but only recently have patients sought more opportunities for engagement and participation in healthcare improvements. This paper brings these two promising trends together, analysing strategies for patient involvement in reducing diagnostic errors in an individuals own care, in improving the healthcare delivery systems diagnostic safety, and in contributing to research and policy development on diagnosis-related issues.

Thrombocytosis Elevates Serum Potassium

Spurious elevation of the serum potassium can be seen if the platelet count exceeds 1,000 x 10(9)/L in patients with myeloproliferative disease. To see if serum potassium is increased at more modest elevations of the platelet count we studied these parameters in 283 controls and 161 patients with reactive thrombocytosis. The incidence of hyperkalemia was 34% in patients with over 500 x 10(9) platelets/L compared with 9% if the platelet count was below 250 x 10(9)/L. Over this range there was a significant correlation of potassium increasing with the platelet count. The higher potassium values could not be explained on the basis of leukocytosis, renal insufficiency, or acidosis, suggesting that the elevated serum levels were often spurious. In support of this conclusion, the serum potassium exceeded plasma potassium by a larger amount in patients with thrombocytosis. We conclude that serum potassium rises in direct proportion to the platelet count in normal patients and in those with thrombocytosis, and that this increment is an artifact.