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.

Differences in triage thresholds for patients presenting with possible acute coronary syndromes: more than meets the eye.

BACKGROUND: Many studies have shown differences in cardiac care by racial/ethnic groups without accounting for institutional factors at the location of care. OBJECTIVE: Exploratory analysis of the effect of hospital funding status (public vs private) on emergency department (ED) triage decision making for patients with symptoms suggestive of acute coronary syndromes (ACSs) and on the likelihood of ED discharge for patients with confirmed ACS. STUDY DESIGN AND SETTING: Secondary analysis of data from a randomized controlled trial of 10,659 ED patients with possible ACS in five urban academic public and five private hospitals. The main outcome measures were the sensitivity and specificity of hospital admission for the presence of ACS at public and private hospitals and the adjusted odds of a patient with ACS not being hospitalized at public versus private hospitals. RESULTS: Of 10,659 ED patients, 1,856 had confirmed ACS. For patients with suspected ACS, triage decisions at private hospitals were considerably more sensitive (99 vs 96%; p<.001) but less specific (30 vs 48%; p<.001) than at public hospitals. The difference between hospital types persisted after adjustment for multiple patient-level and hospital-level characteristics. CONCLUSION: Significant differences in triage for patients with suspected ACS exist between public and private hospital EDs, even after adjustment for multiple patient demographic, clinical, and institutional factors. Further studies are needed to clarify the causes of the differences.

Missed hypothyroidism diagnosis uncovered by linking laboratory and pharmacy data.

BACKGROUND: Although diagnostic errors are important, they have received less attention than medication errors. Timely follow-up of abnormal laboratory test results represents a critical aspect of the diagnostic process, and failures at this step are a cause of delayed or missed diagnosis, resulting in suboptimal clinical outcomes and malpractice litigation. We linked laboratory and pharmacy databases to (1) explore the potential for linking laboratory and pharmacy databases to uncover diagnostic errors, and (2) determine the frequency of failed follow-up of elevated levels of thyroid-stimulating hormone (TSH). METHODS: We downloaded TSH test results for 2 consecutive years from a laboratory database and linked this database with a pharmacy database to screen for patients with TSH levels of 20 mU/mL or higher who were not receiving levothyroxine. Patients with elevated TSH levels lacking prescriptions were followed up by telephone and record review. RESULTS: During the 2-year period, 982 (2.7%) of 36 760 unique patients tested for TSH level had elevated TSH levels. Of these patients, 177 (18.0%) had no recorded levothyroxine prescriptions. We attempted to contact 177 patients with high TSH levels who were not taking thyroid medications and reached 123 (69.5%). Of the 123 patients we were able to reach, 12 in 2000 and 11 in 2001 were unaware of their abnormal test results or a diagnosis of hypothyroidism, representing 2.3% of 982 patients with elevated TSH levels. We were unable to reach another 54 patients (5.5% of the total number of patients with elevated TSH levels) by either telephone or mail. CONCLUSIONS: By linking laboratory and pharmacy databases, we uncovered patients who did not undergo follow-up for abnormal TSH results. Conservatively, there was no follow-up for abnormal TSH results in more than 2% of patients, and another 5% of patients were lost to follow-up and possibly unaware of their results. Uncovering patients with missed diagnosis illustrates a potential use of linking laboratory and pharmacy databases to identify vulnerabilities in the care system and improve patient safety.

Decompensated heart failure: symptoms, patterns of onset, and contributing factors.

PURPOSE: To examine the time course, contributing factors, and patient responses to decompensated heart failure. METHODS: We studied consecutive patients admitted to a public general hospital with a diagnosis of heart failure. Using a timeline follow-back technique, a nurse interviewer administered a questionnaire shortly after admission, exploring knowledge of a heart failure diagnosis, the symptoms and time course of decompensation, and patient responses to worsening symptoms. RESULTS: Of 87 patients, 83 (95%) consented to be interviewed. Only 49 (59%) were aware of the diagnosis of heart failure. Symptoms associated with decompensation included dyspnea in 81 patients (98%), edema in 64 patients (77%), and weight gain in 34 patients (41%). Onset of worsening of these symptoms was noted a mean (+/- SD) of 12.4 +/-1.4 days before admission for edema, 11.3 +/-1.6 days for weight gain, and 8.4 +/- 0.9 days for dyspnea. Forty-two patients (57%) reported missing or skipping medication because of various factors, particularly missed outpatient appointments. CONCLUSION: Using a timeline follow-back interview, we identified a period of days to weeks between the onset of worsening symptoms and hospital admission for heart failure decompensation. This pattern suggests that there is a time window between symptom exacerbation and admission during which earlier access and intervention might prevent hospitalization in these patients. Medication lapses continue to be an important preventable cause of decompensation leading to admission.

A model of medical error based on a model of disease: interactions between adverse events, failures, and their errors.

This article discusses Rush-Presbyterian-St. Luke's Medical Center's approach to assessing and preventing errors in care and promoting patient safety. The word error is applied to all kinds of events, including adverse occurrences, negligence, and malpractice. Thus confusion exists among those analyzing the causes of adverse events. A patient safety committee standardized the definition of medical error and developed a taxonomy for error as a prelude to efforts at error reduction. It identified three levels or layers that can represent a train of events culminating in an undesired outcome: error, treatment failure, and adverse event. This discussion is offered in the interest of clarifying some of the issues.