Frequency, Risk Factors, Causes, and Consequences of Diagnostic Errors in Critically Ill Medical Patients: A Retrospective Cohort Study

OBJECTIVE: Diagnostic errors are a source of significant morbidity and mortality but understudied in the critically ill. We sought to characterize the frequency, causes, consequences, and risk factors of diagnostic errors among unplanned ICU admissions. DESIGN: We conducted a retrospective cohort study of randomly selected nonsurgical ICU admissions between July 2015 and June 2016. SETTING: Medical ICU at a tertiary academic medical center. SUBJECTS: Critically ill adults with unplanned admission to the medical ICU. MEASUREMENTS AND MAIN RESULTS: The primary investigator reviewed patient records using a modified version of the Safer Dx instrument, a validated instrument for detecting diagnostic error. Two intensivists performed secondary reviews of possible errors, and reviewers met periodically to adjudicate errors by consensus. For each confirmed error, we judged harm on a 1-6 rating scale. We also collected detailed demographic and clinical data for each patient. We analyzed 256 unplanned ICU admissions and identified 18 diagnostic errors (7% of admissions). All errors were associated with harm, and only six errors (33%) were recognized by the ICU team within the first 24 hours. More women than men experienced a diagnostic error (11.7% vs 2.7%; p = 0.015, χ test). On multivariable logistic regression analysis, female sex remained independently associated with risk of diagnostic error both at admission (odds ratio, 5.18; 95% CI, 1.34-20.08) and at 24 hours (odds ratio, 11.6; 95% CI, 1.37-98.6). Similarly, Quick Sequential Organ Failure Assessment score greater than or equal to 2 at admission was independently associated with diagnostic error (odds ratio, 5.73; 95% CI, 1.72-19.01). CONCLUSIONS: Diagnostic errors may be an underappreciated source of ICU-related harm. Women and higher acuity patients appear to be at increased risk for such errors. Further research is merited to define the scope of error-associated harm and to clarify risk factors for diagnostic errors among the critically ill.