The outcomes of initial misclassification of undifferentiated hypotension in the emergency department: A prospective observational study

Abstract Background: Managing shock, a life-threatening emergency, is challenging. The influence of initial misclassification of undifferentiated hypotension (UH) in the emergency department (ED) on patients’ outcomes remains un-investigated. Materials and Methods: This prospective observational study enrolled 270 non-traumatic adult patients with UH who had visited the ED of National Taiwan University Hospital between July 2020 and January 2022. The patients were divided into same-diagnosis and different-diagnosis groups, depending on the consistency between the initial and final classifications (in the ED and at discharge, respectively) of shock. The outcome was survival-to-discharge. The clinical variables, management, and outcomes were compared between the groups. Results: Thirty-nine of 270 patients (14.4%) were in the different-diagnosis group. Most patients with misclassification were initially diagnosed as having hypovolemic shock (HS, n = 29), but finally diagnosed as having distributive shock (DS, n = 28) or cardiogenic shock (n = 1). When compared with the same-diagnosis group, the different-diagnosis group had higher hospitalization (94.9% vs. 81.4%, p = 0.023) but lower ED discharge (5.1% vs. 16.5%, p = 0.046) rates. Logistic regression analysis showed HS initially diagnosed was associated with increased risk of misclassification (odds ratio[OR] = 14.731, 95% confidence interval[CI] = 3.572–60.749, p < 0.001). However, the survival-to-discharge did not differ between the two groups. DS, diagnosed at discharge instead of initial misclassification, was associated with in-hospital mortality (OR = 0.317, 95%CI = 0.124–0.810, p = 0.016). Conclusion: Misclassification of UH in the ED is not rare, particularly in patients with DS, who are likely to be initially misdiagnosed with HS. Although misclassification may increase hospitalization and decrease ED discharge, it does not affect survival-to- discharge. Trial registration IRB number: 202005121RINB; ClinicalTrials.gov Identifier: NCT04478045 (date of registration: July 20, 2020)