We read with great interest the article, “Characteristics of patients who return to the emergency department after an observation-unit assessment,” which provides valuable insights into the factors associated with 30-day emergency department (ED) return visit risk [1]. The large sample study underscores the importance of this study in guiding improvements in patient safety by analyzing the risk of return visit [2,3]. However, the results prompt further consideration, particularly concerning the associations between demographic characteristics—such as sex and race—and ED return visits.

While the study identifies significant correlations between sex, race, and 30-day ED return rates, it is unlikely that these demographic factors directly influence the likelihood of clinical deterioration or the need for reevaluation. Instead, these findings raise the possibility of implicit biases in decision-making processes during initial ED or ED observational unit (EDOU) assessments, as has been previously described [4]. For example, prior research has highlighted disparities in evaluation of pain severity and other clinical signs across demographic groups, with women and individuals from certain racial or ethnic backgrounds potentially facing under-assessment of their symptoms or delays in escalated care [5,6]. While this may be difficult to report with an acceptable level of evidence to suggest direct causation, case-vignette studies have clearly suggested that sex, race, or immigrant status, for example, may influence care decisions of emergency physicians [7–9].

In this context, the study findings may reflect lower thresholds for hospitalization among certain populations, driven by clinicians’ perceptions of illness severity rather than actual clinical differences [8]. It can also mirror the possibility of different healthcare access in some underrepresented populations that then are more prone to revisit the ED instead of a general practitioner [10]. This could result in higher rates of EDOU discharge among patients from underrepresented groups, despite their potentially greater risk of subsequent clinical adverse events such as readmission to the ED or hospital. Moreover, the role of insurance status, which also emerged as a significant factor, may exacerbate these disparities by influencing access to outpatient follow-up or continuity of care after EDOU discharge [11].

We encourage the authors to further explore whether the observed differences are mediated by provider-level decision-making, healthcare access inequities, or broader systemic factors [12]. We acknowledge that the authors have used a sound model to adjust several relevant factors, including patient severity. However, this may not have captured physicians’ implicit bias, a well reported issue that needs intervention to limit its impact [13,14].

This study serves as a critical call to action for ED clinicians and policymakers. Addressing these disparities requires a multifaceted approach, including training programs to mitigate implicit biases, standardizing discharge criteria, and improving access to post-EDOU care for vulnerable populations. Further research should aim to disentangle the complex interplay between patient characteristics, provider decision-making, and healthcare systems to ensure equitable care for all [15].