Bruce L. Lambert

Diagnostic Error in Medicine: Analysis of 583 Physician-Reported Errors

BACKGROUND Missed or delayed diagnoses are a common but understudied area in patient safety research. To better understand the types, causes, and prevention of such errors, we surveyed clinicians to solicit perceived cases of missed and delayed diagnoses. METHODS A 6-item written survey was administered at 20 grand rounds presentations across the United States and by mail at 2 collaborating institutions. Respondents were asked to report 3 cases of diagnostic errors and to describe their perceived causes, seriousness, and frequency. RESULTS A total of 669 cases were reported by 310 clinicians from 22 institutions. After cases without diagnostic errors or lacking sufficient details were excluded, 583 remained. Of these, 162 errors (28%) were rated as major, 241 (41%) as moderate, and 180 (31%) as minor or insignificant. The most common missed or delayed diagnoses were pulmonary embolism (26 cases [4.5% of total]), drug reactions or overdose (26 cases [4.5%]), lung cancer (23 cases [3.9%]), colorectal cancer (19 cases [3.3%]), acute coronary syndrome (18 cases [3.1%]), breast cancer (18 cases [3.1%]), and stroke (15 cases [2.6%]). Errors occurred most frequently in the testing phase (failure to order, report, and follow-up laboratory results) (44%), followed by clinician assessment errors (failure to consider and overweighing competing diagnosis) (32%), history taking (10%), physical examination (10%), and referral or consultation errors and delays (3%). CONCLUSIONS Physicians readily recalled multiple cases of diagnostic errors and were willing to share their experiences. Using a new taxonomy tool and aggregating cases by diagnosis and error type revealed patterns of diagnostic failures that suggested areas for improvement. Systematic solicitation and analysis of such errors can identify potential preventive strategies.

Psychometric Evaluation of the 12-Item Short-Form Health Survey (SF-12) in Osteoarthritis and Rheumatoid Arthritis Clinical Trials

BACKGROUND The psychometric properties of the 12-Item Short-Form Health Survey (SF-12), a subset of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), have been tested in the general population and certain disease states. OBJECTIVE The purpose of this study was to evaluate the psychometric properties of the SF-12 as a generic measure of health-related quality of life (HRQoL) in osteoarthritis (OA) and rheumatoid arthritis (RA) patient populations in clinical trials. METHODS Data were aggregated from 5 clinical trials evaluating the efficacy of non-steroidal anti-inflammatory drugs in OA (n = 651) and RA (n = 693) patients. Patient assessments in these trials were made using the SF-36 and commonly used clinical measures of OA and RA at baseline and after up to 6 weeks of treatment. For the items of the SF-36 contained in the SF-12, the item missing rate, computability of scores, floor and ceiling effects, factor structure, and item-component correlations were evaluated. Clinical variables and correlations of physical component summary (PCS-12) and mental component summary (MCS-12) scores of the SF-12 with the corresponding SF-36 component summary scores (PCS-36 and MCS-36) were also examined. Analyses were conducted separately for OA and RA patients. RESULTS A low individual SF-12 item missing rate (0.29% to 2.30%) and a high percentage score computability (90.9%-94.3%) were observed at baseline. No floor or ceiling effects at baseline were observed. The scree plot confirmed the 2-factor structure of the SF-12 items. Items belonging to the physical component correlated more strongly with the PCS-12 than with the MCS-12; similarly, items belonging to the mental component correlated more strongly with the MCS-12 than with the PCS-12. The correlations between the PCS-12 and PCS-36 and between the MCS-12 and MCS-36 ranged from 0.92 to 0.96 (P < 0.001) at baseline and at week 2, 4, or 6. Significant correlations ranging from -0.09 to -0.58 (P < 0.05) were observed between the SF-12 scores and clinical variables. CONCLUSION The SF-12 appears to be a psychometrically sound tool for the assessment of HRQoL in OA and RA patients.

Similarity as a risk factor in drug-name confusion errors: the look-alike (orthographic) and sound-alike (phonetic) model.

BACKGROUND One of every four medication errors reported in the United States is a name-confusion error. The rate of name-confusion errors might be reduced if new and confusing names were not allowed on the market and if safeguards could be put in place to avoid confusion between existing names. OBJECTIVES To evaluate several prognostic tests of drug-name confusion, alone and in combination, with respect to their sensitivity, specificity, and overall accuracy. RESEARCH DESIGN Case-control study. Twenty-two different computerized measures of orthographic similarity, orthographic distance, and phonetic similarity were used to compute similarity/distance scores for n = 1,127 cases (ie, pairs of names that appeared in published error reports or national error databases) and n = 1,127 controls. MAIN OUTCOME MEASURES Mean similarity/distance scores were compared across cases and controls. The performance of each measure at distinguishing between cases and controls was evaluated by tenfold crossvalidation. Dose-response relationships were examined. Univariate and multivariate logistic regression models were formed and evaluated by 10 fold crossvalidation. RESULTS Cases had significantly higher similarity scores than controls. Every measure of similarity proved to be a significant risk factor for error. There was a significant increasing trend in the odds-ratio as a function of similarity. A three-predictor logistic regression model had crossvalidated sensitivity of 93.7%, specificity of 95.9% and accuracy of 94.8%. CONCLUSIONS A sensitive and specific test of drug-name confusion potential can be formed using objective measures of orthographic similarity, orthographic distance, and phonetic distance.

Effect of orthographic and phonological similarity on false recognition of drug names

Health professionals and patients tend to confuse drugs with similar names, thereby threatening patient safety. One out of four medication errors voluntarily reported in the US involves this type of drug name confusion. Cognitive psychology offers insight into how and why these errors occur. The objective of this investigation was to examine the effect of orthographic (i.e., spelling) and phonological (i.e., sound) similarity on the probability of making recognition memory errors (i.e., false recognitions). Prospective, computer-based, recognition memory experiments on 30 pharmacists and 66 college students were conducted. Participants viewed a study list of drug names and then a test list. The test list was twice as long as the study list and contained distractor names at progressively increasing levels of similarity to the study words. The task was to identify which test names were on study list and which were new. The main outcome measure was probability of making a false recognition error (i.e., of saying a new name was on the study list). Among pharmacists and college students, there was a strong and significant effect of similarity on the probability of making a false recognition error. It was concluded that both orthographic (i.e., spelling) and phonological (i.e., sound) similarity increase the probability that experts and novices will make false recognition errors when trying to remember drug names. Similarity is easily and cheaply measured, and therefore, steps should be taken to monitor and reduce similarity as a means of reducing the likelihood of drug name confusions.

A prescription for improving drug formulary decision making.

Gordon Schiff and colleagues present a new tool and checklist to help formularies make decisions about drug inclusion and to guide rational drug use.

The Theory-Ladenness of Observation and the Theory-Ladenness of the Rest of the Scientific Process

We use evidence from cognitive psychology and the history of science to examine the issue of the theory-ladenness of perceptual observation. This evidence shows that perception is theory-laden, but that it is only strongly theory-laden when the perceptual evidence is ambiguous or degraded, or when it requires a difficult perceptual judgment. We argue that debates about the theory-ladenness issue have focused too narrowly on the issue of perceptual experience, and that a full account of the scientific process requires an examination of theory-ladenness in attention, perception, data interpretation, data production, memory, and scientific communication. We conclude that the evidence for theory-ladenness does not lead to a relativist account of scientific knowledge.

Designing Safe Drug Names

Recent observational studies of medication errors in community pharmacies suggest that ‘wrong drug’ errors, which occur when a patient receives a drug other than the one prescribed, may occur as many as 3.9 million times per year in the US. Similarity between drug product attributes, especially similarity between drug names, is thought to be a contributing cause of these errors. The challenge facing drug companies is to design new drug names that will not be confused with existing names. In this paper, we attempt to lay out a systematic approach to the design of safe drug names by characterising the process of design as a multiple-objective optimisation problem. We then identify and define the most important constraints (both technical and legal/regulatory) and objectives (such as meaning, memorability, and pronouncability) that a drug name must satisfy and critique methods for evaluating a given name with respect to each safety objective and constraint.There are a variety of preapproval tests that can be done on a name to test its vulnerability to confusion. These include computerised searches for existing similar names or products, soliciting expert judgements, doing traditional psycholinguistic tests on memory and perception and observing error rates during simulated ordering, dispensing and administration tasks. A different set of strategies is needed to prevent confusion between similar names that are already in use. Preventing confusion between already marketed products typically involves collecting voluntary reports of names involved in confusion errors, posting warnings and alerts both electronically and in areas where drugs are used, including the indication on the prescription, storing confusing drugs in different locations, improving lighting, providing magnifiers, removing one of the confusing drugs from the system or insisting on double-checking for products thought to be vulnerable to confusion.Finally, since no single design will be optimal with respect to all of the objectives, we describe several approaches to selecting one design from a set of competing alternatives. The pharmaceutical industry and the US FDA have taken important steps recently to improve the preapproval screening of new drug names, but a great deal of research still needs to be done to establish a valid scientific basis for these decisions.

Effects of clinical decision support on venous thromboembolism risk assessment, prophylaxis, and prevention at a university teaching hospital

PURPOSE The implementation of a mandatory assessment of risk for venous thromboembolism (VTE) in a health systems electronic medical record (EMR) and clinical decision-support (CDS) system was evaluated to measure its effect on the use of pharmacologic prophylaxis and the occurrence of VTE and bleeding events. METHODS A commercially available CDS system was used in designing the automated CDS intervention. During computerized order entry, the system delivered alerts prompting clinician risk assessment and also delivered alerts under circumstances suggesting less-than-optimal prophylaxis. Rates of pharmacologic prophylaxis, clinically diagnosed hospital-acquired VTE, and hospital-acquired bleeding events were measured during one year before and one year after implementation. RESULTS After adjustment for patient age, sex, and high-risk comorbidities, the data showed a postimplementation increase in the percentage of patients who received pharmacologic prophylaxis at some time during their admission from 25.9% to 36.8% (p < 0.001). The rate of VTE for the entire hospital did not change significantly, but a significant reduction among patients on medical units was observed, from 0.55% to 0.33% (p = 0.02). There was no increase in either major or minor bleeding events. CONCLUSION Without increasing the risk of bleeding, a CDS system requiring clinicians to document VTE risk assessment in the EMR promoted improved rates of pharmacologic prophylaxis at any time during an admission and a decreased risk of VTE in general medical patients but not all adult patients.

Managing the flow of ideas: A local management approach to message design

This chapter develops the case for a local management model of message design. In contrast to other current approaches, in which message structure is understood in terms of holistic-functional categories, a local management approach separates the analysis of message structure and message function. Message structure is understood as patterns of expressed thoughts. Message function is understood in terms of context-sensitive mappings between antecedent conditions and message structure and between message structure and message effects. After making the case for a local management approach, the authors introduce an initial model of the message design process that offers an integrated treatment of message production, adaptation, and effects.

Comparative effectiveness of patient-centered strategies to improve FDA medication guides.

Background:Med Guides are the only Food and Drug Administration-regulated source of written patient information distributed with prescriptions drugs. Despite their potential value, studies have found them to have limited utility. Objective:To evaluate the effectiveness of patient-centered strategies for the design of Med Guides to improve comprehension. Design:A cross-sectional, randomized trial. Setting:Two primary care clinics in Chicago, Illinois; one based in a public university hospital and the other within a private academic medical center. Patients:A total of 1003 adults aged 18–85 years. Intervention:The format and layout of content from 3 typical Med Guides (by reading difficulty, length, exposure) were modified several ways to promote information accessibility. Working with patients, the 3 most preferred versions were evaluated. The first used 2 columns to organize content (Column), a second mimicked over-the-counter “Drug Facts” labeling (Drug Facts), and the third followed health literacy best practices using a simple table format (Health Literacy prototype). Measures:Tailored comprehension assessment of content from 3 representative Med Guides. Results:Comprehension was significantly greater for all 3 prototypes compared with the current standard (all P<0.001). The Health Literacy prototype consistently demonstrated the highest comprehension scores, and in multivariable analyses, outperformed both the Drug Facts [&bgr;=−4.43, 95% confidence interval (CI), −6.21 to −2.66] and Column (&bgr;=−4.04, 95% CI, −5.82 to −2.26) prototypes. Both older age (older than 60 y: &bgr;=−10.54, 95% CI, −15.12 to −5.96), low and marginal literacy skills were independently associated with poorer comprehension (low: &bgr;=−31.92, 95% CI, −35.72 to −28.12; marginal: &bgr;=−12.91, 95% CI, −16.01 to −9.82). Conclusions:The application of evidence-based practices to the redesign of Med Guides significantly improved patient comprehension. Although some age and literacy disparities were reduced with the Health Literacy format in particular, both older age and low literacy remained independently associated with poorer comprehension. More aggressive strategies will likely be needed to gain assurances that all patients are informed about their prescribed medications. Trial Registration:Clinical Trials.Gov #NCT01731405.