Elsevier

The Lancet

Volume 355, Issue 9220, 10 June 2000, Pages 2027-2031
The Lancet

Articles
Diagnostic errors in three medical eras: a necropsy study

https://doi.org/10.1016/S0140-6736(00)02349-7Get rights and content

Summary

Background

Studies comparing the accuracy of clinical diagnosis in unselected patients who died in hospital in different medical eras have shown no decline of errors in the main diagnosis. We assessed changes in diagnostic accuracy over 20 years.

Methods

We analysed retrospectively diagnostic errors, with use of necropsy as the gold standard for diagnosis. We randomly selected 300 patients who died at a tertiary-care teaching hospital in Switzerland-100 in each of 1972, 1982, and 1992. We classified discrepancies between clinical diagnosis and necropsy findings as major and minor errors.

Flndings

The overall necropsy rate at the hostpial stayed at around 90% for the whole period. During the study, the frequency of major discrepancies declined significantly (1972, 30%; 1982, 18%; 1992, 14%; p=0·007). The rate of minor diagnostic errors increased significantly from 23% in 1972 to 46% in 1992 (p<0·001). The increase in overall diagnostic accuracy occurred mainly because of a significant improvement in specificity for cardiovascular diseases (1972, 85%; 1982, 82%; 1992, 97%; p=0·0034) and non-significantly improved sensitivity (1972, 69%; 1982, 82%; 1992, 86%; p=0·0061). Sensitivity also improved for infectious diseases (1972, 25%; 1982, 67%; 1992, 86%; p=0·036). Sensitivity and specificity for neoplastic diseases were high originally and did not change. The total number of diagnostic procedures per year increased from 191 in 1972 to 259, in 1992, mainly because of non-invasive techniques, such as ultrasonography, and endoscopies.

Interpretation

The frequency of major diagnostic errors in unselected patients who died in hospital was halved over 20 years, probably because of improved clinical skills and new diagnostic procedures.

Introduction

The diagnostic process is a complex interaction of cognitive skills and technical procedures in conditions of uncertainty.1 Diagnostic procedures have been improved over the past 30 years. No data, however, show decreases in diagnostic errors in unselected patients, with necropsy as the gold standard for diagnosis. Postmortem examination is the only way to assess overall clinical diagnostic performance, since clinicians can diagnose only diseases for which they have been looking.2 Two studies comparing clinical diagnoses with necropsy findings in different medical eras showed no improvement in diagnostic accuracy over time in unselected patients.3, 4 Diagnostic accuracy depends on sensitivity and specificity of the diagnostic process. The use of diagnostic accuracy as a sole criterion for judging discrepancies between clinical and necropsy diagnoses may obscure what occurs during the diagnostic process.5 To improve clinical practice, it is important to know whether diagnostic errors occur because of lack of sensitivity or specificity of the diagnostic work-up. We assessed the changes in overall accuracy over 20 years, as well as accuracy, sensitivity, and specificity for the three major categories of diseases, to gain more insight into the process of clinical diagnosis.

Section snippets

Selection of cases

We analysed retrospectively the medical and necropsy records of 300 randomly selected adult patients admitted to the Medical Clinic at the University Hospital, Zurich, Switzerland-100 from each of 1972, 1982, and 1992. 1972 was chosen because the oldest complete set of case notes was available from this year. Random sampling was done with a random-number table6 from the list of patients who died in the Medical Clinic and underwent necropsy.

The role of the University Hospital Zurich, and Medical

Results

The characteristics of patients were similar in each year. The number of patients with previous admissions or with two or more admissions was, however, slightly lower among patients in 1982 (table 2). The necropsy rate was 94·0% in 1972 and 89·2% in 1982 and 1992. Cardiovascular diseases were the largest diagnostic group, followed by neoplastic diseases (table 1). Infectious diseases were the third largest diagnostic group of the study patients in 1992, of whom six had HIV-1 infection.

The

Discussion

The frequency of major diagnostic errors have been reduced significantly since the early 1970s. This improvement was due mainly to a decline in the frequency of errors in the diagnosis of cardiovascular diseases

Two previous studies showed an unchanged rate of major discrepancies between clinical and postmortem diagnosis.3, 4 In those two studies, the rate of necropsy dropped from 80% to lower than 40% in the last year of study. This reduction could have masked improved clinical performance

References (19)

There are more references available in the full text version of this article.

Cited by (197)

  • Quality of care and maternal mortality in a tertiary-level hospital in Mozambique: a retrospective study of clinicopathological discrepancies

    2020, The Lancet Global Health
    Citation Excerpt :

    Another possible limitation of the study is that, although we met three of the four conditions proposed for complete diagnostic autopsy to monitor clinical diagnosis performance,24 we did not assess the error of the autopsy itself, which would have required a specific study. Finally, a possible limitation could be the disagreement rate of more than 20% in error assignment in this study, although this figure is not dissimilar from previously reported data.25 Most actions and programmes focused on maternal and neonatal mortality reduction rely on imprecise information on the actual causes of maternal mortality.

  • A Practical Guide to Assess the Reproducibility of Echocardiographic Measurements

    2019, Journal of the American Society of Echocardiography
View all citing articles on Scopus
View full text