Association between comorbid mental illness and preceding emergency department visits in unplanned admissions

INTRODUCTION

Treatment of physical illness in patients with comorbid mental illness is a persistent existential issue that has gathered widespread attention across broad geographies in recent years. The life expectancy of patients with mental illness is 10–15 years shorter than patients without mental issues.^1-4 Most premature deaths of the patients with mental illness are not a result of suicide, but instead attributed to physical illnesses.^{3, 5} Multiple studies have contributed to the general consensus that mental illness is a risk factor for lifestyle-related diseases.^6-8

Further fueling this complexity, patients with mental illness have been challenged with apparent inequalities in the standard of care granted when compared with patients without mental issues.^{6, 8, 9} For example, patients with mental illness tend to receive fewer opportunities to undergo invasive coronary procedures after cardiac events.⁸ The emergency department (ED) is an essential common ground for patients presenting with a variety of physical manifestations of disease regardless of the presence or absence of underlying mental illness. Given the previously reported disparities in the quality of care granted to patients with comorbid mental illness,^{7, 9} patients with mental illness who visit the ED may be inadequately assessed; however, inequalities in the emergency and urgent care setting remain poorly documented. Therefore, the present study aimed to investigate the association between comorbid mental illness and prevalence of preceding ED visits in patients with unplanned hospital admissions.

MATERIALS AND METHODS

RESULTS

Patient flow

During the study period, the database recorded 16,542 patients with unplanned admissions. Of these, we identified 15,429 patients including 766 (5%) in the mental illness group and 14,663 in the non-mental illness group (Fig. 1).

DISCUSSION

The present study investigated the association between comorbid mental illness and preceding ED visits in patients with unplanned hospital admissions. The presence of comorbid mental illness was significantly associated with a higher prevalence of preceding ED visits within 30 days prior to the unplanned admission.

Several studies have reported on the inequality of physical treatment for patients with mental illness in outpatient and inpatient settings.^{6-8, 19} For example, patients with mental illness were less likely to be prescribed statins for dyslipidemia than those without and receive invasive coronary procedures after cardiac events.^{8, 19} Assessments of the mental condition of patients with mental illness presenting to the ED have been previously reported.^20-22 However, studies focusing on the assessment of the physical illness in patients with mental illness in ED settings are limited. We investigated the association between comorbid mental illness and preceding ED visits in patients with unplanned hospital admissions in a multicenter setting.

The underlying mechanisms of our findings are likely multifactorial. First, physicians in the EDs may tend to underestimate the physical condition of patients with comorbid mental illness.²³ Second, patients with mental illness could not be hospitalized at the timing of the preceding ED visit for reasons such as social, financial, and psychiatric problems regardless of the recommendations of physicians in the EDs.²⁴ Lastly, physical illness of patients with mental illness may deteriorate more rapidly than expected due to daily habits and the problems of adherence.^{5, 25, 26}

The present study suggests the likelihood of an opportunity to intervene in the physical illness of patients with comorbid mental illness prior to unplanned admissions. The unplanned admission is not entirely due to the underestimation of ED physicians. Introducing social services such as connecting patients with mental illness to the local public welfare office might be efficient to mitigate unplanned admissions in this subset of patients. A lower threshold for initiating objective testing and examinations should also be considered for patients with mental illness because it may be difficult to obtain an accurate and comprehensive history from these patients. When discharging these patients to their home environments from the ED, we suggest that social resources be checked and scrutinized to ensure that appropriate medical and psychiatric continuity of care can be provided.

Our study has several potential limitations. First, the diagnosis at the ED and medical history were manually recorded by ED physicians. Because the definition of comorbid mental illness of this study was based on medical records, misclassification of the exposure would influence the results. Second, our data do not include the information on whether the patients refused to be hospitalized at the first ED visit regardless of the recommendation for hospitalization by ED physicians. Third, we identified only revisits to the EDs in the same facility. Therefore, the patients who revisit or were hospitalized at other facilities after the preceding ED visit could not be identified. This might be a potential source of selection bias. Fourth, the threshold for ED visits may be lower among patients with mental illness. This is inferred from the higher prevalence of ambulance use among patients with mental illness. Because ambulance use was adopted as a surrogate marker for assessing patient severity, the differences in clinical severity between the two groups may not have been sufficiently adjusted for. Finally, the present study was performed in Japan and the results might not be applicable to other countries with different emergency medical systems. While the multicenter design could, at least partially enhance the generalizability, further investigation on the potential influence of having mental conditions on the screening process currently undertaken at the preceding ED visits is warranted.

CONCLUSION

Among the patients with unplanned admission via EDs, the presence of mental illness was significantly associated with a higher prevalence of preceding ED visits within 30 days prior to the unplanned admission. ED physicians should grant extra attention to patients with comorbid mental illness so as not to miss the opportunity to treat them on their initial ED visits. Our findings warrant further investigation on the potential influence of having mental conditions on the screening process currently undertaken at the preceding ED visits.

FUNDING INFORMATION

TS is the SIP AI hospital research project chief researcher funded by the Japanese Cabinet Office.

DISCLOSURE

Approval of the Research Protocol with Approval No. and Committee Name: The present study was approved by the Institutional Review Board at TXP Medical Co. Ltd. (approval number: TXPREC-002).

Informed Consent: Because of the anonymous nature of the data, the requirement for patient informed consent was waived.

Registry and the Registration No. of the Study/Trial: N/A.

Animal Studies: N/A.

Conflict of Interest: AO and MN are part-time employees of TXP Medical Co. Ltd. TG is the Chief Scientific Officer, TXP Medical Co. Ltd. TS is the Chief Executive Officer, TXP Medical Co. Ltd. None of the authors received any financial incentives for this work from TXP Medical Co. Ltd. TXP Medical Co. Ltd. may gain potential profit from the manuscript acceptance, such as the use of results to introduce the NEXT Stage ER system.