Etiology and mortality of patients with altered level of consciousness in the emergency room: a multicenter analysis before and after the coronavirus disease 2019 outbreak

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The COVID-19 pandemic has impacted healthcare systems globally, influencing ER dynamics. This study compared ALC before (BC) and after (AC) the coronavirus disease 2019 outbreak, focusing on etiology, disposition, and outcomes. This was a retrospective, multicenter study of four university hospitals in charge of an area of about five million people in South Korea. All cases were reviewed within a consortium of board-certified faculties and compared between BC (February 2018 to January 2020) and AC (March 2021 to February 2023. We reviewed to find 17,913 patients who visited the ER due to ALC, of whom 7,988 and 9,925 were in BC and AC, respectively. The overall incidence of ALC in the ER was 3.1%, higher in AC (BC vs. AC, 2.5% vs. 3.7%, p < 0.001). The most common etiology was Metabolic cause (24.8%), followed by Systemic infection (18.0%). Intracranial etiologies accounted for 29.7% of the total. Hospitalization rate increased from BC to AC (54.5–59.3%, p < 0.001). The overall mortality was 16.2%, and 5.3% of the patients with ALC died in the ER. ALCs dut to cardiogenic and vascular etiology had the highest mortality (26.8%). This study marks the first investigation on ALC in the ER comparing BC and AC. Emergency room Emergency medical services Consciousness disorders Neurologic manifestations COVID-19 Figures Figure 1 Figure 2 Introduction A new-onset altered level of consciousness (ALC), characterized by non-physiological changes in arousal or attention, poses a significant challenge in the emergency room (ER). ALC necessitates focused medical attention because it is a critical clinical condition in the ER. ALC has been reported to account for approximately 4–10% of ER visits [ 1 , 2 ]. ALC in the ER is not a diagnosis but rather a symptom with a diverse spectrum, including confusion, disorientation, lethargy, somnolence, unresponsiveness, coma, agitation, inattention, hallucinations, delusions, psychosis, or inappropriate behavior [ 3 ]. The complexity of these terms has led to abstract and inconsistent characteristics in research, since the study population or etiology classification system was different for each study [ 4 – 9 ]. The period analyzed was only 14 days in one study in the early days [ 10 ], another study had a short study period of 4 months [ 3 ], and a recent study evaluated only 47 days [ 11 ]. Some studies set the analysis target for suspicious alcohol intoxication only [ 12 ], trauma only [ 13 ], or elderly patients only [ 10 , 14 ]. In addition, the researchers involved in the causal analysis were affiliated with a single department in several studies [ 3 , 5 , 13 ], and there was a study that adopted chief complaint rather than objective examination as the criteria for ALC [ 8 ]. Consequently, the variations make it challenging to pursue follow-up studies. Recently, a multicenter study introduced ALC-10, an etiology classification system, of which Metabolic cause, Systemic infection, and Stroke were reported as major etiology [ 15 ]. However, most studies were conducted before the coronavirus disease 2019 (COVID-19) outbreak. COVID-19, caused by severe acute respiratory syndrome coronavirus-2, has significantly impacted the healthcare system as well as the socio-economic landscape since the World Health Organization declared a public health emergency of the global outbreak of COVID-19 in January 2020. There has been a noticeable fluctuation in the volume of patients seeking health care, changes in national health policy, healthcare delivery systems, and emergency department utilization. Recent studies reported that the COVID-19 outbreak has led to a decline in demand for hospital-based emergency services [ 16 – 18 ], whereas some studies reported an increase in mortality after the COVID-19 outbreak (AC) [ 19 – 21 ]. This led to a change in clinical practice in the ER. For instance, considerations such as response protocols for febrile illnesses where infection cannot be excluded, obligatory COVID-19 screening tests for admission, and alterations in patient distribution and flow from the ER have emerged. In the ER, ALC is one of the critical symptoms of intensive allocation of medical resources. In order to maintain adaptability and responsiveness in clinical practice, it is imperative to evaluate and scrutinize ALC before the COVID-19 outbreak (BC) and AC. Despite its clinical significance, research on ALC in the ER still needs to be improved; moreover, few studies are focusing on ALC in AC. This study aimed to address this gap by investigating the etiologies, destinations, and outcomes of ALC, comparing BC with AC. Methods This is a retrospective multi-center study of four university hospitals, which is covering approximately 5 million individuals in Daegu (a metropolitan city) and adjacent regions (Gyeongsangbuk-do province and part of Gyeongsangnam-do province) in South Korea. The Institutional Review Boards (IRBs) of Daegu Catholic University Medical Center (CR-20–217), Keimyung University Dongsan Medical Center (2022-09-068), Kyungpook National University Hospital (2020–11–060), and Yeungnam University Medical Center (2021–06–059) approved this study. Written informed consent was waived due to the retrospective study design. In order to investigate ALCs in the ER and compare BC with AC, we set the BC and AC as follows: BC stands for the 2 years preceding the first COVID-19 case found on February 18 in South Korea, from February 2018 to January 2020. AC designates the period from March 2021 to February 2023, characterized by a discernible semblance to the new normal. This timeframe corresponds to the phase following the initiation of COVID-19 vaccination efforts in South Korea, commencing on February 26, 2021. Given the substantial disruptions caused by the global impact of the COVID-19 pandemic, the disruptive period from February 2020 to February 2021 (referred to as "coronapocalypse")—including frequent policy changes, occasional ER closures, resource shortages, and insufficient workforce—was excluded from the analysis. Patients This study adopted the methods of the previous study [ 15 ], from which the data from BC were derived. All patients’ Glasgow Coma Scale (GCS) scores were assessed by the first medical doctor, who was either the chief resident or a faculty member of the department of emergency medicine. In this study, ALC encompasses (1) GCS < 15; (2) impaired orientation (person, place, and time); (3) ALC in the evaluation of the first GCS examiner (e.g., hallucinations, confusion, or abnormal/inappropriate behavior). Exclusion criteria were: (1) the initial GCS = 15; (2) age < 18; (3) transferred during hospitalization at another hospital; (4) Cardiac arrest or death on arrival; and (5) Revisit within 48 hours of discharge from ER. Classification and arrangement of the etiologies Each patient presenting with ALC in the ER underwent a comprehensive review of their medical records, categorized according to the 10-etiology classification system of ALC (ALC-10): [ 15 ] (1) Metabolic cause, (2) Systemic infection, (3) Cardiogenic and vascular (C&V), (4) Stroke, (5) Traumatic brain injury (TBI), (6) Seizure, (7) Central nervous system (CNS) infection, (8) Toxic, (9) Psychiatric disorder, and (10) Undetermined. Notably, the reference time point for determining the etiology of ALC was upon the patient's departure from the ER; subsequently, the provisional diagnosis might differ from the definitive diagnosis. A multidisciplinary approach guided the review of medical records, involving a consortium of board-certified professors specialized in emergency medicine, internal medicine, and neurology. The consortium held monthly meetings with all members presented. The etiology classification and provisional diagnosis were determined through case-by-case discussions within the consortium. Patients were systematically reviewed upon the comprehensive scrutiny of pertinent information such as age, sex, ER visit time, vital signs, medical history, physical and neurological evaluations, electrocardiography, X-rays, laboratory tests, echocardiography, computed tomography, magnetic resonance imaging, electroencephalography, and cerebrospinal fluid analysis. Statistical analysis The statistics used were mainly descriptive. We compared BC and AC, using the t-test or chi-square test for continuous and categorical variables, respectively. A p -value < 0.05 was considered statistically significant. IBM SPSS Statistics for Windows 22.0 (IBM Corp., NY, USA) was used for data analysis. Results Demographic characteristics The total volume of ER visits reached 583,353, consisting of 315,526 and 267,827 in BC and AC, respectively (Fig. 1 ). Following the exclusion, a total of 17,913 cases were further stratified into two temporal categories: BC, encompassing 7,988 cases; and AC, comprising 9,925 cases. In this study, the overall incidence of ALC in the ER was 3.1% ([17,913 / 583,353] * 100 ≈ 3.07%), with a higher incidence in AC period compared to BC (BC vs. AC, 2.5% vs. 3.7% of total ER visits in BC, p < 0.001). Regarding sex distribution, females constituted 47.6%, with 46.2% in BC and 48.8% in AC ( p = 0.001). The mean age was 66.64 ± 18.07 years overall, higher in AC (BC vs. AC, 65.50 ± 17.91 vs. 67.55 ± 18.16, p < 0.001) (Table 1 ). The proportion of elderly individuals aged 60 years or older in AC surpassed that in BC (BC vs. AC, [ n = 5282, 66.1%] vs. [ n = 7044, 71.0%], p < 0.001), and over 50% of individuals aged 70 years or older in BC (BC vs. AC, [ n = 3937, 49.3%] vs. [ n = 5398, 54.4%], p < 0.001). The mean length of stay in the ER was 14.66 ± 19.48 hours in overall. This was reduced in AC (13.91 ± 17.74) compared to BC (15.59 ± 21.41) (p < 0.001). The lengths of stay in the ER exhibited significant reductions for two leading etiologies of ALC in the ER: Metabolic cause (BC vs. AC, 18:58 ± 24:22 vs. 15:44 ± 19:38, p < 0.001) and Systemic infection (BC vs. AC, 25:14 ± 27:29 vs. 18:43 ± 19:44, p < 0.001) (Supplementary Table 2). Undetermined also showed a significant reduction in AC (BC vs. AC, 14:06 ± 17.43 vs. 11:58 ± 15:00, p = 0.032). The mean admission length of the patients with ALC in the ER was 17.97 ± 23.36 days. In BC and AC, the mean durations of admission were 18.26 ± 24.76 and 17.76 ± 22.27 days, respectively, with no significant difference observed ( p = 0.280). Table 1 Demographic data and the etiologies of altered level of consciousness in the emergency room. Variables Total ( n = 17913) BC ( n = 7988) AC ( n = 9925) p -value Female 8532 (47.6) 3690 (46.2) 4842 (48.8) 0.001* Age (years ± SD) 66.64 ± 18.07 65.50 ± 17.91 67.55 ± 18.16 < 0.001 \(\le\) 29 920 (5.1) 410 (5.1) 510 (5.1) < 0.001* 30–39 846 (4.7) 400 (5.0) 446 (4.5) 40–49 1410 (7.9) 727 (9.1) 683 (6.9) 50–59 2411 (13.5) 1169 (14.6) 1242 (12.5) 60–69 2991 (16.7) 1345 (16.8) 1646 (16.6) 70–79 4093 (22.8) 1859 (23.3) 2234 (22.5) 80–89 4407 (24.6) 1780 (22.3) 2627(26.5) \(\ge\) 90 835 (4.7) 298 (3.7) 537 (5.4) Length of stay in the ER (HH:MM) 14.39 ± 19.48 15.59 ± 21.41 13.91 ± 17.74 < 0.001 Metabolic cause 17:10 ± 21:55 18:58 ± 24:22 15:44 ± 19:38 < 0.001 Systemic infection 21:30 ± 23:34 25:14 ± 27:29 18:43 ± 19:44 < 0.001 C&V 12:37 ± 19:46 13:41 ± 18:23 12:01 ± 20:30 0.230 Stroke 07:48 ± 12:04 07:31 ± 13:49 08:04 ± 10:04 0.261 TBI 07:01 ± 10:00 07:04 ± 10:39 06:59 ± 09:20 0.839 Toxic 15:05 ± 18:45 14:52 ± 18:33 15:15 ± 18:54 0.610 Seizure 14:01 ± 16:51 13:47 ± 17:02 14:15 ± 16:40 0.675 CNS infection 19:44 ± 17:27 18:25 ± 17:21 21:39 ± 17:31 0.206 Psychiatric disorder 12:09 ± 13:34 12:28 ± 15:20 11:54 ± 12:01 0.735 Undetermined 12.42 ± 16:00 14:06 ± 17.43 11:58 ± 15:00 0.032 Length of admission (days) 17.97 ± 23.36 18.26 ± 24.76 17.76 ± 22.27 0.280 All statistics are t-test, except for *: Chi-square test. Abbreviations: BC: before COVID-19, AC: after COVID-19, SD: standard deviation, ER: emergency room, C&V: cardiogenic and vascular, TBI: traumatic brain injury, CNS: central nervous system. Etiologies of ALC The most prevalent etiology was Metabolic cause, accounting for 24.8% of the total (Fig. 2 and Supplementary Table 1). There was no significant difference between BC (24.7%) and AC (24.8%) ( p = 0.842). Systemic infection was identified in 18.0% of the total, increasing from 17.3% in BC to 18.7% in AC ( p = 0.015). Toxic constituted 14.3%, with a non-significant difference between BC (14.0%) and AC (14.5%) ( p = 0.384). Stroke, the most common intracranial etiology, ranked fourth, accounting for 13.1% of the total. It held the third position in BC (14.6%) but dropped to the fourth in AC (11.9%) ( p < 0.001). TBI constituted 10.1% of cases overall, with a higher incidence in BC (11.3%) compared to AC (9.1%) ( p < 0.001). ALC in the ER due to Seizure accounted for 5.4% in total and was higher in BC than AC (6.1% vs. 4.9%, p < 0.001). C&V constituted 4.6% and increased from 3.7% in BC to 5.4% in AC ( p < 0.001). Psychiatric disorder was 1.5% of the total, without a significant difference between BC and AC ( p = 0.961). CNS infection was identified in 1.1% of cases overall, decreasing from 1.4% in BC to 0.8% in AC ( p < 0.001). Undetermined accounted for 7.1% of the total; there was a statistically significant difference between BC (5.5%) and AC (8.4%) ( p < 0.001). The three major extra-cranial etiologies (i.e., Metabolic cause, Systemic infection, and Toxic accounted for 57.1% ( n = 10,222) of the total, with 56.0% ( n = 4,470) and 58.0% ( n = 5,752) in BC and AC, respectively. The intracranial etiologies, including Stroke, TBI, Seizure, and CNS infection, were 29.7% ( n = 5327), consisting of 33.4% ( n = 2668) and 26.8% ( n = 2659) in BC and AC, respectively. Dispositions from the ER and post-admission destinations The overall hospitalization rate of ALC in the ER was 57.2%. This rate increased significantly from 54.5% in BC to 59.3% in AC ( p < 0.001). Including patients transferred to other hospitals, the overall hospitalization rate rose to 69.3%. Table 2 and Fig. 1 show dispositions from the ER and post-admission destinations. Although intensive care unit (ICU) was the most common disposition overall and in BC (28.8% and 31.8%, respectively), ICU admissions decreased in AC (31.8% vs. 26.3%, p < 0.001). The surge in general ward (GW) admissions exceeded that of the ICU, and GW became the most common destination in AC period (BC vs. AC, 22.6% vs. 33.0%, p < 0.001). Transfer to another hospital, accounting for 12.1% of the total, decreased in AC compared to BC (BC vs. AC, 15.2% vs. 9.7%, p < 0.001). A quarter (25.4%) of the patients with ALC in the ER were discharged home without admission, with no significant difference between BC (25.4%) and AC (25.7%) ( p = 0.425). It is noteworthy that more than 5% of patients presenting to the ER with ALC died in the ER without admission or transfer (5.3%). There was a significant increase in death in the ER from 4.6% in BC to 5.8% in AC ( p < 0.001). In the entire study period, 63.3% of deaths in the ER were either Metabolic cause or Systemic infection, which accounted for 71.0% and 58.3% in BC and AC, respectively (Supplementary Table 2). Regarding post-admission destinations, home discharge accounted for the majority at 56.7%, despite a decline from 59.0% in BC to 55.0% in AC ( p < 0.001). Transfer to another hospital remained constant at 24.1%, with no significant difference between BC and AC ( p = 0.209). The post-admission mortality rate increased significantly from 16.3% in BC to 21.3% in AC, corresponding to 19.2% of all patients admitted due to ALC in the ER in this study ( p < 0.001). Table 2 Dispositions and destinations of patients with altered level of consciousness Total BC AC p -value Dispositions from the ER (N = 17913) ( n = 7988) ( n = 9925) ICU 5157 (28.8) 2544 (31.8) 2613 (26.3) < 0.001 GW 5085 (28.4) 1808 (22.6) 3277 (33.0) < 0.001 Home 4552 (25.4) 2053 (25.7) 2499 (25.2) 0.425 Transfer 2174 (12.1) 1214 (15.2) 960 (9.7) < 0.001 Death in the ER 945 (5.3) 369 (4.6) 576 (5.8) < 0.001 Destinations on discharge after admission (N = 10242) ( n = 4352) ( n = 5890) Home 5810 (56.7) 2568 (59.0) 3242 (55.0) < 0.001 Transfer 2469 (24.1) 1076 (24.7) 1393 (23.7) 0.209 Death 1963 (19.2) 708 (16.3) 1255 (21.3) < 0.001 Chi-square test; Numbers are n (%). Abbreviations: BC: before COVID-19, AC: after COVID-19, GW: general ward, ICU: intensive care unit, ER: emergency room, Transfer: transferred to another hospital. Mortalities of altered level of consciousness in the ER The mortality outcomes associated with the etiologies and the overall mortality of the patients with ALC in the ER are illustrated in Table 3 . The overall mortality was 16.2%, with a significant increase in AC compared to BC (BC vs. AC, 13.5% vs. 18.4%, p < 0.001). Metabolic cause showed a mortality rate of 17.4% with a significant increase in AC compared to BC (BC vs. AC, 13.1% vs. 20.8%, p < 0.001). Systemic infection also showed a higher mortality rate in AC (25.3%) than in BC (21.0%) ( p = 0.004), and its mortality in total was 23.4%. C&V had the highest mortality of 26.8%, and there was no significant difference between the two periods (BC vs. AC, 24.8% vs. 28.0%, p = 0.330). Stroke, the most common intra-cranial etiology of ALC in the ER, showed a mortality rate of 19.6%. Its mortality was significantly higher in AC (24.7%) than in BC (14.8%) ( p < 0.001). The mortality rate of Toxic was 3.1% in total, higher in AC compared to BC (BC vs. AC, 2.2% vs. 3.8%, p = 0.022). Notably, ALC due to Undetermined revealed a mortality rate of 14.6%, with a significantly higher rate in AC than BC (BC vs. AC, 11.0% vs. 16.5%, p = 0.008). TBI and CNS infection showed similar mortality (19.1%), and they had no significant difference between BC and AC (TBI and CNS infection, p = 0.898 and p = 0.088). There was no death in the ER from CNS infection (Supplementary Table 2). The mortalities of Seizure and Psychiatric disorder were 3.7% and 2.3%, respectively, without significant difference between BC and AC, either (Seizure and Psychiatric disorder, p = 0.088 and p = 0.579). Table 3 Mortality by etiology and overall Total BC AC p -value Overall mortality 2908 (16.2) 1077 (13.5) 1831(18.4) < 0.001 Metabolic cause 772 (17.4) 259 (13.1) 513 (20.8) < 0.001 Systemic infection 757 (23.4) 289 (21.0) 468 (25.3) 0.004 C&V 223 (26.8) 74 (24.8) 149 (28.0) 0.330 Stroke 466 (19.8) 173 (14.8) 293 (24.7) < 0.001 TBI 345 (19.1) 173 (19.2) 172 (19.0) 0.898 Toxic 80 (3.1) 25 (2.2) 55 (3.8) 0.022 Seizure 36 (3.7) 13 (2.7) 23 (4.7) 0.088 CNS infection 37 (19.1) 21 (18.3) 16 (20.3) 0.729 Psychiatric disorder 6 (2.3) 2 (1.7) 4 (2.8) 0.579 Undetermined 186 (14.6) 48 (11.0) 138 (16.5) 0.008 Chi-square test; Numbers are n (%). Abbreviations: BC: before COVID-19, AC: after COVID-19, SD: standard deviation, C&V: cardiogenic and vascular, TBI: traumatic brain injury, CNS: central nervous system. Discussions The well-developed Korean healthcare and delivery system significantly contributes to the reliability of this study. South Korea operates a mandatory government-operated health insurance policy that covers the entire population, ensuring a robust healthcare delivery system with low private pay. In addition, the timely transfer of critically ill patients, including those with ALC, to the ERs of university hospitals is a standard process in place. ALC accounted for 3.1% of all ER visits in this study. This figure should be interpreted in light of the healthcare environment in South Korea, where a low entry threshold in ERs results in a high proportion of mild cases. The ERs in the four participating university hospitals operate comprehensive availability of year-round, 24 hours a day, enabling ALC patients to undergo immediate diagnostic tests, including blood tests, X-rays, electrocardiography, electroencephalography, transthoracic echocardiography, computed tomography, and magnetic resonance imaging. In addition, emergency interventions, such as emergency operations, extracorporeal membrane oxygenation, ultrasound-guided interventions, and endovascular treatment for cerebrovascular diseases, are available anytime if required. The ALC-10 classification, employed in this research, is a consortium-based etiology classification system. As described, board-certified faculty members of the neurology, internal medicine, and emergency medicine departments conducted a comprehensive review with discussions based on medical records. They currently participate in ER patient management, and the classification process follows real-world protocol. This exhaustive case-by-case review process, involving in-depth discussions, was challenging and time-consuming; nevertheless, we have kept this process to maintain high reliability and consistency. Consequently, the etiology classification and the disposition from the ER were made after almost all essential investigations, interventions, and responses based on initial medical requirements; therefore, this study may represent real-world practices of ER based on medical needs. Given the potentially life-threatening nature of ALC per se, it presents a complex challenge in the ER. Effective management requires vigilant medical staff, comprehensive history-taking, well-established medical protocols, appropriate diagnostic approaches, prompt assessments, and tailored interventions. The dynamic and continuous attribute of consciousness, coupled with the often elusive identification of underlying causes, amplifies the complexity of the research designs on ALC in the ER. The inconsistent definition associated with ALC in previous studies and real-world practice, including terms synonymous with loss of consciousness, impaired consciousness, mental change, and altered mental status, goes beyond a mere variety in terminology, signifying its nonspecific nature with diverse etiologies. In order to address these limitations, we reviewed 17,913 cases out of 583,353 ER visits to four university hospitals, spanning 2 years in both BC and AC, respectively. The outcomes, offering foundational insights into ALC in the ER, illuminate various facets of real-world clinical practice, covering demographic characteristics, etiology, dispositions from the ER, and post-hospitalization outcomes. To the best of our knowledge, this study includes the most extensive population in research related to ALC in the ER and marks the first investigation on ALC in the ER comparing BC and AC. When stratifying age into 10-year intervals from the 20s, there was a decrease in the proportion of patients below 60. In contrast, those aged 60 and above showed an increment—patients aged 70 and above constituted over fifty percent of the total, especially in AC. The mean ages reported in previous studies ranged from 49 to 69,[ 5 , 6 , 8 , 9 , 22 , 23 ] compatible with our study. Nevertheless, a closer look at previous studies shows that the mean age is higher in recent studies compared to earlier studies. The mean ages were reported as 49 and 45 in 2002 and in 2008, respectively [ 5 , 7 ]. Subsequently, Forsberg et al. and Xiao et al. reported 59 and 51 in 2009 and 2012,[ 6 , 9 ] respectively. Data from the late 2010s showed that the mean age reached the late 60s [ 8 , 22 , 23 ]. While the proportion of sex varies from study to study, the age of ALC in the ER tends to increase. The overall length of stay in the ER was shortened in AC by approximately 2 hours, which suggests improved patient distribution and disposition from the ER in AC. There were about 4- and 6-hour reductions in Metabolic cause and Systemic infection, respectively. These two etiologies account for approximately 42% of the patients with ALC in the ER and mainly suggest non-surgical problems. There was no difference in vascular diseases such as C&V and Stroke, which implies that the same level of intervention protocol as BC was carried out in time. According to the opinion of the consortium members in this study, hospitalizations have increased while the number of transfers has decreased, leading to a reduction in the time required to make decisions about dispositions. In BC, patients with ALC attributed to Metabolic causes or Systemic infection could be transferred to another hospital when conservative management was only required. However, under COVID-19 guidelines in AC, early transfer became challenging, leading to an increased hospitalization rate. Consequently, patients with ALC experienced shorter stays in the ER, and the hospitalization rate increased, which resulted in a shorter ER stay time for ALC patients. In essence, changes in administration and healthcare delivery system facilitated earlier decisions for hospitalization, thereby reducing ER stay time. In AC, there was a decrease in the proportion of ICU admissions, while GW admissions showed a significant increase due to the abovementioned reasons. The leading etiology sent to the ICU was Stroke: The allocation of ICU involves issues regarding the distribution of limited medical resources. (i.e., the limited number of ICU beds). Moreover, it does not imply a decrease in critical patients with ALC requiring ICU management. This distribution analysis focuses on the increased hospitalization rate to either the ICU or GW for patients with ALC, alongside a decrease in transfer and an increase in death in the ER. The decreased transfer also represents herding behavior in the healthcare delivery system [ 24 , 25 ], while death in the ER implies death pending ICU admission. Consequently, we need alignment in the healthcare delivery system between the classes of hospitals and enhancement of bed turnover rates of ICU in university hospitals. Additional research and interventions are needed regarding the mortality linked to ALC caused by metabolic causes or systemic infections during ER stays, as indicated by this study's findings. The overall mortality in this study was 16.2%, amounting to 2908 deaths, with 1278 in ICU, 685 in GW, and 945 within the ER. The mortality rate for hospitalized patients is 19.1%. Mortality rates of GW and ICU were 13.5% and 24.8%, respectively, with higher mortality rates among those admitted to ICU ( p < 0.001). These results are consistent with previous studies, ranging from 7–27% [ 4 , 6 , 7 ]. It is nearly impossible to stratify the cause of death because of the myriad complications that may arise. Nonetheless, we observed that C&V had the highest mortality rate in BC, followed by Systemic infection. This pattern persisted in AC, but the Stroke and Metabolic cause became the third and fourth. In general medical disorders, an increase in mortality has already been reported in AC [ 19 – 21 ]. Since a history of COVID-19 infection per se has been reported to be a risk factor for higher mortality [ 26 – 28 ], the increased mortality in Metabolic cause, Systemic infection, Stroke, and undeterred were believed to be directly attributed to the impact of COVID-19. Previous studies of mortality in ER suggested that the causes of increased mortality included delayed access to healthcare services, misalignment of resource distribution, and overcrowding of ER in AC [ 17 , 21 , 29 , 30 ]. Regarding Toxic, according to the ALC-10 classification criteria, it encompasses ALCs caused by ingestion or inhalation of toxic materials (alcohol, insecticides ingestion, or adverse drug reactions), regardless of intent. It is well known that depression and suicide increased in AC [ 31 – 35 ]. Based on the authors' experience in the ER, there has been an increase in binge drinking or drug administration associated with feelings of hopelessness or suicidal intentions after the onset of COVID-19. Besides, there has been a tendency to transfer such cases to university hospitals in hospitals with limited resources because addressing toxic cases involves the exclusion of alternative causes. Consequently, we surmise that the increased mortality rate of Toxic is more likely a secondary effect of changes in the healthcare delivery system and the increase in psychological distress, such as "long COVID." In the etiology classification, the numbers of Metabolic cause, Systemic infection, Toxic, C&V, and Psychiatric disorder have increased. Nevertheless, only systemic infections and C&V showed statistically significant increases in AC compared to BC. In contrast, there were several etiologies of a significant decrease in the proportion: Stroke, TBI, and Seizure. Notably, the number of patients remained similar despite the decline in proportions. It is reasonable to conclude that while the incidence of Stroke, TBI, and Seizure did not decrease, the number of cases involving Metabolic cause, Systemic infection, Toxic, C&V, and Psychiatric disorder increased, with Systemic infection and C&V showing particularly significant increases—the only etiology of a significant decrease in the proportion as well as the number was CNS infection. The increased incidence of Systemic infection in AC resulted from the increased incidence of sepsis or septic shock associated with COVID-19 infection [ 36 – 39 ]. Regarding C&V, it is well known that COVID-19 is associated with myocarditis, myocardial infarction, arrhythmia, and heart failure [ 40 – 42 ], which could result in cardiogenic shock. In addition, recent studies reported that not only COVID-19 per se but also COVID-19 vaccination were associated with the risk of cardiogenic shock [ 43 – 45 ]. This is another evidence to support the increased C&V in this study. ALC in the ER increased in AC, and the significant increase in the incidence of ALC by Systemic infection and C&V in AC would have been a direct impact of COVID-19. In many studies [ 4 – 9 , 11 , 13 ], the primary etiology of ALC in the ER has been identified as intracranial (e.g., neurological, stroke, seizure, dementia). However, our study demonstrated that the main etiologies of ALC in the ER were extra-cranial. This does not diminish the significance of intracranial etiology; instead, it emphasizes the need for a multidisciplinary approach to addressing ALC in the ER without underestimating intracranial causes. In addition, it is notable that Undetermined accounted for more than 7% of the total, while the unknown etiologies, so-called "Others" or "Miscellaneous," did 3–9% in previous studies [ 4 , 8 , 9 ]. The significant numbers suggest that the cause of ALC in the ER can remain inconclusive despite an intensive assessment lasting more than 10 hours and may require additional medical access. Undetermined encompassed unknown causes, two or more causes and not classified elsewhere in this study. It is widely acknowledged that diagnoses made in the ER are provisional, and distinguishing between multiple causes can be highly challenging [ 15 ]; however, Undetermined is a significant etiology classification with a mortality rate of as high as 16% in AC. Our consortium's discussed and agreed opinion is that Undetermined, i.e., the etiology of unknown, should be accepted as a characteristic of ALC in the ER. In the management of ALC in the ER, what we need in ALC in the ER is not a hasty name but an appropriate assessment and reasonable measure, even after discharge from the ER. Thus, additional medical assessments, including admission and multidisciplinary approaches, should be considered. Several limitations merit consideration in interpreting the study findings. The retrospective nature of the study is an inherent bias. Second, a single ethnic background should be considered. Lastly, the interpretation should be contextualized within the healthcare landscape in South Korea. However, this study offers a comprehensive exploration of ALC in the ER, including the change of etiology, demographic shift, disposition, and prognosis based on data from approximately 18,000 subjects in 4 years. The observed shifts in ALC patterns between BC and AC indicate a discernible evolution in emergency care dynamics over time, ostensibly influenced by the COVID-19 pandemic. This suggests the imperative for sustained vigilance in organizing healthcare strategies that adapt to the dynamic healthcare landscape. Further prospective studies with continued data collection that can represent the healthcare environment for each center should be encouraged. Declarations Acknowledgement: The authors wish to thank and acknowledge Soo-yeon Yoon for her invaluable work on data processing. This study was supported by a grant from Korean Neurological Association (KNA-22-SK-17). Disclosure of Conflict of Interest: The authors have no potential conflicts of interest to disclose. Author Contributions Conceptualization: KT.K, DH.K Investigation, Data curation, Formal analysis, and Validation: All authors Project administration: KT.K, DH.K., JA.P., JG.S. Visualization: KT.K. Writing—original draft: KT.K. Writing—review & editing: All authors References American College of Emergency Physicians (1999) Clinical policy for the initial approach to patients presenting with altered mental status. 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CNS Drugs 36:681-702. https://doi.org/10.1007/s40263-022-00931-3 Renaud-Charest O, Lui LMW, Eskander S, Ceban F, Ho R, Di Vincenzo JD et al (2021) Onset and frequency of depression in post-COVID-19 syndrome: a systematic review. J Psychiatr Res 144:129-137. https://doi.org/10.1016/j.jpsychires.2021.09.054 Stang JL, DeVries PA, Klein LR, Cole JB, Martel M, Reing ML et al (2021) Medical needs of emergency department patients presenting with acute alcohol and drug intoxication. Am J Emerg Med 42:38-42. https://doi.org/10.1016/j.ajem.2020.12.079 de Araújo GC, Pardini A, Lima C (2023) The impact of comorbidities and COVID-19 on the evolution of community onset sepsis. Sci Rep 13:10589. https://doi.org/10.1038/s41598-023-37709-6 Shappell CN, Klompas M, Chan C, Chen T, Kanjilal S, McKenna C, Rhee C (2023) Use of electronic clinical data to track incidence and mortality for SARS-CoV-2-associated sepsis. JAMA Netw Open 6:e2335728. https://doi.org/10.1001/jamanetworkopen.2023.35728 Heubner L, Hattenhauer S, Güldner A, Petrick PL, Rößler M, Schmitt J et al (2022) Characteristics and outcomes of sepsis patients with and without COVID-19. J Infect Public Health 15:670-676. https://doi.org/10.1016/j.jiph.2022.05.008 Karakike E, Giamarellos-Bourboulis EJ, Kyprianou M, Fleischmann-Struzek C, Pletz MW, Netea MG et al (2021) Coronavirus disease 2019 as cause of viral sepsis: a systematic review and meta-analysis. Crit Care Med 49:2042-2057. https://doi.org/10.1097/ccm.0000000000005195 Agdamag ACC, Edmiston JB, Charpentier V, Chowdhury M, Fraser M, Maharaj VR et al (2020) Update on COVID-19 myocarditis. Medicina (Kaunas) 56. https://doi.org/10.3390/medicina56120678 Salabei JK, Asnake ZT, Ismail ZH, Charles K, Stanger GT, Abdullahi AH et al (2022) COVID-19 and the cardiovascular system: an update. Am J Med Sci 364:139-147. https://doi.org/10.1016/j.amjms.2022.01.022 Adeghate EA, Eid N, Singh J (2021) Mechanisms of COVID-19-induced heart failure: a short review. Heart Fail Rev 26:363-369. https://doi.org/10.1007/s10741-020-10037-x Guglin ME, Etuk A, Shah C, Ilonze OJ (2023) Fulminant myocarditis and cardiogenic shock following COVID-19 infection versus COVID-19 vaccination: a systematic literature review. J Clin Med 12. https://doi.org/10.3390/jcm12051849 Witberg G, Barda N, Hoss S, Richter I, Wiessman M, Aviv Y et al (2021) Myocarditis after Covid-19 vaccination in a large health care organization. N Engl J Med 385:2132-2139. https://doi.org/10.1056/NEJMoa2110737 Yasmin F, Najeeb H, Naeem U, Moeed A, Atif AR, Asghar MS et al (2023) Adverse events following COVID-19 mRNA vaccines: a systematic review of cardiovascular complication, thrombosis, and thrombocytopenia. Immun Inflamm Dis 11:e807. https://doi.org/10.1002/iid3.807 Supplementary Files SupplementaryTables.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3987446","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":294240037,"identity":"c8e73604-8eb7-4944-914f-a9e6366325be","order_by":0,"name":"Keun Tae Kim","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAwklEQVRIiWNgGAWjYBACfh7+B0DKBogZGw8QpUWyhwdEpYG0NBCnxQCi5TCYQ6QWnrPHpAtqztutbT8MtKXGJpqgFnPevjTpGcduJ287kwjUciwtt4GQFst+BjNpHrbbyWYHgFoYGw4T1mJwHqTl37lks/MPidVytsdMmrftgJ3ZDWJtkew5lmw9sy85wewG0JYEYvzCz5N88HbBNzt7s/PpDx98qLEhrAUEmIE4EawygRjlMC32xCoeBaNgFIyCEQgAZX1Fwm0JKJYAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-7124-0736","institution":"Keimyung University School of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Keun","middleName":"Tae","lastName":"Kim","suffix":""},{"id":294240038,"identity":"d155540d-2614-4f37-8a12-8c3b4bb25dd2","order_by":1,"name":"Jong-Geun Seo","email":"","orcid":"","institution":"Kyungpook National University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Jong-Geun","middleName":"","lastName":"Seo","suffix":""},{"id":294240039,"identity":"a00c99ee-6c44-48a6-9ad1-3701a8fb744b","order_by":2,"name":"Jung A Park","email":"","orcid":"","institution":"Daegu Catholic University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Jung","middleName":"A","lastName":"Park","suffix":""},{"id":294240040,"identity":"beb20fff-7716-4d5b-99e8-2d9ebe77ab1d","order_by":3,"name":"Chang‑Gyu Jung","email":"","orcid":"","institution":"Keimyung University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Chang‑Gyu","middleName":"","lastName":"Jung","suffix":""},{"id":294240041,"identity":"e4659027-e3fa-4016-a1ee-f28238cc82c2","order_by":4,"name":"Jae Cheon Jeon","email":"","orcid":"","institution":"Keimyung University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Jae","middleName":"Cheon","lastName":"Jeon","suffix":""},{"id":294240042,"identity":"1001dd63-31ff-4397-bbea-f07c5d704fd0","order_by":5,"name":"Doo Hyuk Kwon","email":"","orcid":"","institution":"Yeungnam University School of Medicine and College of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Doo","middleName":"Hyuk","lastName":"Kwon","suffix":""}],"badges":[],"createdAt":"2024-02-25 09:00:37","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3987446/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3987446/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":55536995,"identity":"c2d4ef3f-6627-451d-b913-c36f18e3579b","added_by":"auto","created_at":"2024-04-29 16:39:56","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":17815,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart of patients including dispositions and destinations. ER: emergency room, GCS: Glasgow Coma Scale, ALC: altered level of consciousness, GW: general ward, ICU: intensive care unit, Transfer: transferred to another hospital.\u003c/p\u003e","description":"","filename":"BCvsAC2vs2years1.png","url":"https://assets-eu.researchsquare.com/files/rs-3987446/v1/3a80acb2b7bcef72ec29cd5b.png"},{"id":55536996,"identity":"3eb468a3-15a3-4052-96ce-1ed39dfc5abc","added_by":"auto","created_at":"2024-04-29 16:39:56","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":89483,"visible":true,"origin":"","legend":"\u003cp\u003eEtiology of altered level of consciousness in the emergency room. Data are presented as n (%). CNS: central nervous system, C\u0026amp;V: cardiogenic \u0026amp; vascular, TBI: traumatic brain injury\u003c/p\u003e","description":"","filename":"BCvsAC2vs2years2.png","url":"https://assets-eu.researchsquare.com/files/rs-3987446/v1/e84c1234bab641d3172537bb.png"},{"id":70143289,"identity":"c80f8221-965f-4473-a18b-73f960c39e53","added_by":"auto","created_at":"2024-11-28 20:56:36","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":628316,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3987446/v1/3bb76548-05cd-4b87-869c-d52d25470aa8.pdf"},{"id":55536994,"identity":"dbe28a8c-f248-4835-8e19-be78c74d2e18","added_by":"auto","created_at":"2024-04-29 16:39:56","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":37587,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryTables.docx","url":"https://assets-eu.researchsquare.com/files/rs-3987446/v1/5a8561f5a9166e94891e4038.docx"}],"financialInterests":"","formattedTitle":"Etiology and mortality of patients with altered level of consciousness in the emergency room: a multicenter analysis before and after the coronavirus disease 2019 outbreak","fulltext":[{"header":"Introduction","content":"\u003cp\u003eA new-onset altered level of consciousness (ALC), characterized by non-physiological changes in arousal or attention, poses a significant challenge in the emergency room (ER). ALC necessitates focused medical attention because it is a critical clinical condition in the ER. ALC has been reported to account for approximately 4\u0026ndash;10% of ER visits [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. ALC in the ER is not a diagnosis but rather a symptom with a diverse spectrum, including confusion, disorientation, lethargy, somnolence, unresponsiveness, coma, agitation, inattention, hallucinations, delusions, psychosis, or inappropriate behavior [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe complexity of these terms has led to abstract and inconsistent characteristics in research, since the study population or etiology classification system was different for each study [\u003cspan additionalcitationids=\"CR5 CR6 CR7 CR8\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The period analyzed was only 14 days in one study in the early days [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], another study had a short study period of 4 months [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], and a recent study evaluated only 47 days [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Some studies set the analysis target for suspicious alcohol intoxication only [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], trauma only [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], or elderly patients only [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. In addition, the researchers involved in the causal analysis were affiliated with a single department in several studies [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], and there was a study that adopted chief complaint rather than objective examination as the criteria for ALC [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Consequently, the variations make it challenging to pursue follow-up studies. Recently, a multicenter study introduced ALC-10, an etiology classification system, of which Metabolic cause, Systemic infection, and Stroke were reported as major etiology [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. However, most studies were conducted before the coronavirus disease 2019 (COVID-19) outbreak.\u003c/p\u003e \u003cp\u003eCOVID-19, caused by severe acute respiratory syndrome coronavirus-2, has significantly impacted the healthcare system as well as the socio-economic landscape since the World Health Organization declared a public health emergency of the global outbreak of COVID-19 in January 2020. There has been a noticeable fluctuation in the volume of patients seeking health care, changes in national health policy, healthcare delivery systems, and emergency department utilization. Recent studies reported that the COVID-19 outbreak has led to a decline in demand for hospital-based emergency services [\u003cspan additionalcitationids=\"CR17\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], whereas some studies reported an increase in mortality after the COVID-19 outbreak (AC) [\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. This led to a change in clinical practice in the ER. For instance, considerations such as response protocols for febrile illnesses where infection cannot be excluded, obligatory COVID-19 screening tests for admission, and alterations in patient distribution and flow from the ER have emerged.\u003c/p\u003e \u003cp\u003eIn the ER, ALC is one of the critical symptoms of intensive allocation of medical resources. In order to maintain adaptability and responsiveness in clinical practice, it is imperative to evaluate and scrutinize ALC before the COVID-19 outbreak (BC) and AC. Despite its clinical significance, research on ALC in the ER still needs to be improved; moreover, few studies are focusing on ALC in AC. This study aimed to address this gap by investigating the etiologies, destinations, and outcomes of ALC, comparing BC with AC.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eThis is a retrospective multi-center study of four university hospitals, which is covering approximately 5\u0026nbsp;million individuals in Daegu (a metropolitan city) and adjacent regions (Gyeongsangbuk-do province and part of Gyeongsangnam-do province) in South Korea. The Institutional Review Boards (IRBs) of Daegu Catholic University Medical Center (CR-20\u0026ndash;217), Keimyung University Dongsan Medical Center (2022-09-068), Kyungpook National University Hospital (2020\u0026ndash;11\u0026ndash;060), and Yeungnam University Medical Center (2021\u0026ndash;06\u0026ndash;059) approved this study. Written informed consent was waived due to the retrospective study design.\u003c/p\u003e \u003cp\u003eIn order to investigate ALCs in the ER and compare BC with AC, we set the BC and AC as follows: BC stands for the 2 years preceding the first COVID-19 case found on February 18 in South Korea, from February 2018 to January 2020. AC designates the period from March 2021 to February 2023, characterized by a discernible semblance to the new normal. This timeframe corresponds to the phase following the initiation of COVID-19 vaccination efforts in South Korea, commencing on February 26, 2021. Given the substantial disruptions caused by the global impact of the COVID-19 pandemic, the disruptive period from February 2020 to February 2021 (referred to as \"coronapocalypse\")\u0026mdash;including frequent policy changes, occasional ER closures, resource shortages, and insufficient workforce\u0026mdash;was excluded from the analysis.\u003c/p\u003e \u003cp\u003ePatients\u003c/p\u003e \u003cp\u003eThis study adopted the methods of the previous study [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], from which the data from BC were derived. All patients\u0026rsquo; Glasgow Coma Scale (GCS) scores were assessed by the first medical doctor, who was either the chief resident or a faculty member of the department of emergency medicine. In this study, ALC encompasses (1) GCS\u0026thinsp;\u0026lt;\u0026thinsp;15; (2) impaired orientation (person, place, and time); (3) ALC in the evaluation of the first GCS examiner (e.g., hallucinations, confusion, or abnormal/inappropriate behavior). Exclusion criteria were: (1) the initial GCS\u0026thinsp;=\u0026thinsp;15; (2) age\u0026thinsp;\u0026lt;\u0026thinsp;18; (3) transferred during hospitalization at another hospital; (4) Cardiac arrest or death on arrival; and (5) Revisit within 48 hours of discharge from ER.\u003c/p\u003e \u003cp\u003eClassification and arrangement of the etiologies\u003c/p\u003e \u003cp\u003eEach patient presenting with ALC in the ER underwent a comprehensive review of their medical records, categorized according to the 10-etiology classification system of ALC (ALC-10): [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] (1) Metabolic cause, (2) Systemic infection, (3) Cardiogenic and vascular (C\u0026amp;V), (4) Stroke, (5) Traumatic brain injury (TBI), (6) Seizure, (7) Central nervous system (CNS) infection, (8) Toxic, (9) Psychiatric disorder, and (10) Undetermined. Notably, the reference time point for determining the etiology of ALC was upon the patient's departure from the ER; subsequently, the provisional diagnosis might differ from the definitive diagnosis.\u003c/p\u003e \u003cp\u003eA multidisciplinary approach guided the review of medical records, involving a consortium of board-certified professors specialized in emergency medicine, internal medicine, and neurology. The consortium held monthly meetings with all members presented. The etiology classification and provisional diagnosis were determined through case-by-case discussions within the consortium. Patients were systematically reviewed upon the comprehensive scrutiny of pertinent information such as age, sex, ER visit time, vital signs, medical history, physical and neurological evaluations, electrocardiography, X-rays, laboratory tests, echocardiography, computed tomography, magnetic resonance imaging, electroencephalography, and cerebrospinal fluid analysis.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eThe statistics used were mainly descriptive. We compared BC and AC, using the t-test or chi-square test for continuous and categorical variables, respectively. A \u003cem\u003ep\u003c/em\u003e-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant. IBM SPSS Statistics for Windows 22.0 (IBM Corp., NY, USA) was used for data analysis.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eDemographic characteristics\u003c/p\u003e \u003cp\u003eThe total volume of ER visits reached 583,353, consisting of 315,526 and 267,827 in BC and AC, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Following the exclusion, a total of 17,913 cases were further stratified into two temporal categories: BC, encompassing 7,988 cases; and AC, comprising 9,925 cases. In this study, the overall incidence of ALC in the ER was 3.1% ([17,913 / 583,353] * 100\u0026thinsp;\u0026asymp;\u0026thinsp;3.07%), with a higher incidence in AC period compared to BC (BC vs. AC, 2.5% vs. 3.7% of total ER visits in BC, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Regarding sex distribution, females constituted 47.6%, with 46.2% in BC and 48.8% in AC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001). The mean age was 66.64\u0026thinsp;\u0026plusmn;\u0026thinsp;18.07 years overall, higher in AC (BC vs. AC, 65.50\u0026thinsp;\u0026plusmn;\u0026thinsp;17.91 vs. 67.55\u0026thinsp;\u0026plusmn;\u0026thinsp;18.16, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The proportion of elderly individuals aged 60 years or older in AC surpassed that in BC (BC vs. AC, [\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;5282, 66.1%] vs. [\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;7044, 71.0%], p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and over 50% of individuals aged 70 years or older in BC (BC vs. AC, [\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;3937, 49.3%] vs. [\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;5398, 54.4%], \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The mean length of stay in the ER was 14.66\u0026thinsp;\u0026plusmn;\u0026thinsp;19.48 hours in overall. This was reduced in AC (13.91\u0026thinsp;\u0026plusmn;\u0026thinsp;17.74) compared to BC (15.59\u0026thinsp;\u0026plusmn;\u0026thinsp;21.41) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The lengths of stay in the ER exhibited significant reductions for two leading etiologies of ALC in the ER: Metabolic cause (BC vs. AC, 18:58\u0026thinsp;\u0026plusmn;\u0026thinsp;24:22 vs. 15:44\u0026thinsp;\u0026plusmn;\u0026thinsp;19:38, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and Systemic infection (BC vs. AC, 25:14\u0026thinsp;\u0026plusmn;\u0026thinsp;27:29 vs. 18:43\u0026thinsp;\u0026plusmn;\u0026thinsp;19:44, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Supplementary Table\u0026nbsp;2). Undetermined also showed a significant reduction in AC (BC vs. AC, 14:06\u0026thinsp;\u0026plusmn;\u0026thinsp;17.43 vs. 11:58\u0026thinsp;\u0026plusmn;\u0026thinsp;15:00, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.032). The mean admission length of the patients with ALC in the ER was 17.97\u0026thinsp;\u0026plusmn;\u0026thinsp;23.36 days. In BC and AC, the mean durations of admission were 18.26\u0026thinsp;\u0026plusmn;\u0026thinsp;24.76 and 17.76\u0026thinsp;\u0026plusmn;\u0026thinsp;22.27 days, respectively, with no significant difference observed (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.280).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic data and the etiologies of altered level of consciousness in the emergency room.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;17913)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBC (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;7988)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAC (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;9925)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8532 (47.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3690 (46.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4842 (48.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e66.64\u0026thinsp;\u0026plusmn;\u0026thinsp;18.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e65.50\u0026thinsp;\u0026plusmn;\u0026thinsp;17.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e67.55\u0026thinsp;\u0026plusmn;\u0026thinsp;18.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\le\\)\u003c/span\u003e\u003c/span\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e920 (5.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e410 (5.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e510 (5.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"7\" rowspan=\"8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u0026ndash;39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e846 (4.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e400 (5.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e446 (4.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e40\u0026ndash;49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1410 (7.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e727 (9.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e683 (6.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e50\u0026ndash;59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2411 (13.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1169 (14.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1242 (12.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e60\u0026ndash;69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2991 (16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1345 (16.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1646 (16.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e70\u0026ndash;79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4093 (22.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1859 (23.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2234 (22.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e80\u0026ndash;89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4407 (24.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1780 (22.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2627(26.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\ge\\)\u003c/span\u003e\u003c/span\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e835 (4.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e298 (3.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e537 (5.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLength of stay in the ER (HH:MM)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14.39\u0026thinsp;\u0026plusmn;\u0026thinsp;19.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15.59\u0026thinsp;\u0026plusmn;\u0026thinsp;21.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13.91\u0026thinsp;\u0026plusmn;\u0026thinsp;17.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMetabolic cause\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17:10\u0026thinsp;\u0026plusmn;\u0026thinsp;21:55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18:58\u0026thinsp;\u0026plusmn;\u0026thinsp;24:22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15:44\u0026thinsp;\u0026plusmn;\u0026thinsp;19:38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSystemic infection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21:30\u0026thinsp;\u0026plusmn;\u0026thinsp;23:34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25:14\u0026thinsp;\u0026plusmn;\u0026thinsp;27:29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18:43\u0026thinsp;\u0026plusmn;\u0026thinsp;19:44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u0026amp;V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12:37\u0026thinsp;\u0026plusmn;\u0026thinsp;19:46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13:41\u0026thinsp;\u0026plusmn;\u0026thinsp;18:23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12:01\u0026thinsp;\u0026plusmn;\u0026thinsp;20:30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.230\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStroke\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e07:48\u0026thinsp;\u0026plusmn;\u0026thinsp;12:04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e07:31\u0026thinsp;\u0026plusmn;\u0026thinsp;13:49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e08:04\u0026thinsp;\u0026plusmn;\u0026thinsp;10:04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.261\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTBI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e07:01\u0026thinsp;\u0026plusmn;\u0026thinsp;10:00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e07:04\u0026thinsp;\u0026plusmn;\u0026thinsp;10:39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e06:59\u0026thinsp;\u0026plusmn;\u0026thinsp;09:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.839\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eToxic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15:05\u0026thinsp;\u0026plusmn;\u0026thinsp;18:45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14:52\u0026thinsp;\u0026plusmn;\u0026thinsp;18:33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15:15\u0026thinsp;\u0026plusmn;\u0026thinsp;18:54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.610\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSeizure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14:01\u0026thinsp;\u0026plusmn;\u0026thinsp;16:51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13:47\u0026thinsp;\u0026plusmn;\u0026thinsp;17:02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14:15\u0026thinsp;\u0026plusmn;\u0026thinsp;16:40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.675\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCNS infection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19:44\u0026thinsp;\u0026plusmn;\u0026thinsp;17:27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18:25\u0026thinsp;\u0026plusmn;\u0026thinsp;17:21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e21:39\u0026thinsp;\u0026plusmn;\u0026thinsp;17:31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.206\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePsychiatric disorder\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12:09\u0026thinsp;\u0026plusmn;\u0026thinsp;13:34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12:28\u0026thinsp;\u0026plusmn;\u0026thinsp;15:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11:54\u0026thinsp;\u0026plusmn;\u0026thinsp;12:01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.735\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUndetermined\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.42\u0026thinsp;\u0026plusmn;\u0026thinsp;16:00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14:06\u0026thinsp;\u0026plusmn;\u0026thinsp;17.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11:58\u0026thinsp;\u0026plusmn;\u0026thinsp;15:00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.032\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLength of admission (days)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17.97\u0026thinsp;\u0026plusmn;\u0026thinsp;23.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.26\u0026thinsp;\u0026plusmn;\u0026thinsp;24.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17.76\u0026thinsp;\u0026plusmn;\u0026thinsp;22.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.280\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eAll statistics are t-test, except for *: Chi-square test. Abbreviations: BC: before COVID-19, AC: after COVID-19, SD: standard deviation, ER: emergency room, C\u0026amp;V: cardiogenic and vascular, TBI: traumatic brain injury, CNS: central nervous system.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eEtiologies of ALC\u003c/p\u003e \u003cp\u003eThe most prevalent etiology was Metabolic cause, accounting for 24.8% of the total (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Supplementary Table\u0026nbsp;1). There was no significant difference between BC (24.7%) and AC (24.8%) (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.842). Systemic infection was identified in 18.0% of the total, increasing from 17.3% in BC to 18.7% in AC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.015). Toxic constituted 14.3%, with a non-significant difference between BC (14.0%) and AC (14.5%) (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.384). Stroke, the most common intracranial etiology, ranked fourth, accounting for 13.1% of the total. It held the third position in BC (14.6%) but dropped to the fourth in AC (11.9%) (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). TBI constituted 10.1% of cases overall, with a higher incidence in BC (11.3%) compared to AC (9.1%) (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). ALC in the ER due to Seizure accounted for 5.4% in total and was higher in BC than AC (6.1% vs. 4.9%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). C\u0026amp;V constituted 4.6% and increased from 3.7% in BC to 5.4% in AC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Psychiatric disorder was 1.5% of the total, without a significant difference between BC and AC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.961). CNS infection was identified in 1.1% of cases overall, decreasing from 1.4% in BC to 0.8% in AC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Undetermined accounted for 7.1% of the total; there was a statistically significant difference between BC (5.5%) and AC (8.4%) (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The three major extra-cranial etiologies (i.e., Metabolic cause, Systemic infection, and Toxic accounted for 57.1% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;10,222) of the total, with 56.0% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;4,470) and 58.0% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;5,752) in BC and AC, respectively. The intracranial etiologies, including Stroke, TBI, Seizure, and CNS infection, were 29.7% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;5327), consisting of 33.4% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2668) and 26.8% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2659) in BC and AC, respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eDispositions from the ER and post-admission destinations\u003c/p\u003e \u003cp\u003eThe overall hospitalization rate of ALC in the ER was 57.2%. This rate increased significantly from 54.5% in BC to 59.3% in AC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Including patients transferred to other hospitals, the overall hospitalization rate rose to 69.3%. Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e show dispositions from the ER and post-admission destinations. Although intensive care unit (ICU) was the most common disposition overall and in BC (28.8% and 31.8%, respectively), ICU admissions decreased in AC (31.8% vs. 26.3%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The surge in general ward (GW) admissions exceeded that of the ICU, and GW became the most common destination in AC period (BC vs. AC, 22.6% vs. 33.0%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Transfer to another hospital, accounting for 12.1% of the total, decreased in AC compared to BC (BC vs. AC, 15.2% vs. 9.7%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). A quarter (25.4%) of the patients with ALC in the ER were discharged home without admission, with no significant difference between BC (25.4%) and AC (25.7%) (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.425). It is noteworthy that more than 5% of patients presenting to the ER with ALC died in the ER without admission or transfer (5.3%). There was a significant increase in death in the ER from 4.6% in BC to 5.8% in AC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). In the entire study period, 63.3% of deaths in the ER were either Metabolic cause or Systemic infection, which accounted for 71.0% and 58.3% in BC and AC, respectively (Supplementary Table\u0026nbsp;2). Regarding post-admission destinations, home discharge accounted for the majority at 56.7%, despite a decline from 59.0% in BC to 55.0% in AC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Transfer to another hospital remained constant at 24.1%, with no significant difference between BC and AC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.209). The post-admission mortality rate increased significantly from 16.3% in BC to 21.3% in AC, corresponding to 19.2% of all patients admitted due to ALC in the ER in this study (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDispositions and destinations of patients with altered level of consciousness\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDispositions from the ER\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;17913)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;7988)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;9925)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eICU\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5157 (28.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2544 (31.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2613 (26.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGW\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5085 (28.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1808 (22.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3277 (33.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHome\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4552 (25.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2053 (25.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2499 (25.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.425\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTransfer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2174 (12.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1214 (15.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e960 (9.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeath in the ER\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e945 (5.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e369 (4.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e576 (5.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDestinations on discharge after admission\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;10242)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;4352)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;5890)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHome\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5810 (56.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2568 (59.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3242 (55.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTransfer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2469 (24.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1076 (24.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1393 (23.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.209\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeath\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1963 (19.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e708 (16.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1255 (21.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eChi-square test; Numbers are \u003cem\u003en\u003c/em\u003e (%). Abbreviations: BC: before COVID-19, AC: after COVID-19, GW: general ward, ICU: intensive care unit, ER: emergency room, Transfer: transferred to another hospital.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eMortalities of altered level of consciousness in the ER\u003c/p\u003e \u003cp\u003eThe mortality outcomes associated with the etiologies and the overall mortality of the patients with ALC in the ER are illustrated in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The overall mortality was 16.2%, with a significant increase in AC compared to BC (BC vs. AC, 13.5% vs. 18.4%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Metabolic cause showed a mortality rate of 17.4% with a significant increase in AC compared to BC (BC vs. AC, 13.1% vs. 20.8%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Systemic infection also showed a higher mortality rate in AC (25.3%) than in BC (21.0%) (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.004), and its mortality in total was 23.4%. C\u0026amp;V had the highest mortality of 26.8%, and there was no significant difference between the two periods (BC vs. AC, 24.8% vs. 28.0%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.330). Stroke, the most common intra-cranial etiology of ALC in the ER, showed a mortality rate of 19.6%. Its mortality was significantly higher in AC (24.7%) than in BC (14.8%) (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The mortality rate of Toxic was 3.1% in total, higher in AC compared to BC (BC vs. AC, 2.2% vs. 3.8%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.022). Notably, ALC due to Undetermined revealed a mortality rate of 14.6%, with a significantly higher rate in AC than BC (BC vs. AC, 11.0% vs. 16.5%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.008). TBI and CNS infection showed similar mortality (19.1%), and they had no significant difference between BC and AC (TBI and CNS infection, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.898 and \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.088). There was no death in the ER from CNS infection (Supplementary Table\u0026nbsp;2). The mortalities of Seizure and Psychiatric disorder were 3.7% and 2.3%, respectively, without significant difference between BC and AC, either (Seizure and Psychiatric disorder, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.088 and \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.579).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMortality by etiology and overall\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOverall mortality\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2908 (16.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1077 (13.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1831(18.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMetabolic cause\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e772 (17.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e259 (13.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e513 (20.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSystemic infection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e757 (23.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e289 (21.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e468 (25.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.004\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u0026amp;V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e223 (26.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e74 (24.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e149 (28.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.330\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStroke\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e466 (19.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e173 (14.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e293 (24.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTBI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e345 (19.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e173 (19.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e172 (19.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.898\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eToxic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e80 (3.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e25 (2.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e55 (3.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.022\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSeizure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e36 (3.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e13 (2.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e23 (4.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.088\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCNS infection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e37 (19.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e21 (18.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16 (20.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.729\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePsychiatric disorder\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6 (2.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2 (1.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4 (2.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.579\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUndetermined\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e186 (14.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e48 (11.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e138 (16.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.008\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eChi-square test; Numbers are \u003cem\u003en\u003c/em\u003e (%). Abbreviations: BC: before COVID-19, AC: after COVID-19, SD: standard deviation, C\u0026amp;V: cardiogenic and vascular, TBI: traumatic brain injury, CNS: central nervous system.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussions","content":"\u003cp\u003eThe well-developed Korean healthcare and delivery system significantly contributes to the reliability of this study. South Korea operates a mandatory government-operated health insurance policy that covers the entire population, ensuring a robust healthcare delivery system with low private pay. In addition, the timely transfer of critically ill patients, including those with ALC, to the ERs of university hospitals is a standard process in place. ALC accounted for 3.1% of all ER visits in this study. This figure should be interpreted in light of the healthcare environment in South Korea, where a low entry threshold in ERs results in a high proportion of mild cases.\u003c/p\u003e \u003cp\u003eThe ERs in the four participating university hospitals operate comprehensive availability of year-round, 24 hours a day, enabling ALC patients to undergo immediate diagnostic tests, including blood tests, X-rays, electrocardiography, electroencephalography, transthoracic echocardiography, computed tomography, and magnetic resonance imaging. In addition, emergency interventions, such as emergency operations, extracorporeal membrane oxygenation, ultrasound-guided interventions, and endovascular treatment for cerebrovascular diseases, are available anytime if required. The ALC-10 classification, employed in this research, is a consortium-based etiology classification system. As described, board-certified faculty members of the neurology, internal medicine, and emergency medicine departments conducted a comprehensive review with discussions based on medical records. They currently participate in ER patient management, and the classification process follows real-world protocol. This exhaustive case-by-case review process, involving in-depth discussions, was challenging and time-consuming; nevertheless, we have kept this process to maintain high reliability and consistency. Consequently, the etiology classification and the disposition from the ER were made after almost all essential investigations, interventions, and responses based on initial medical requirements; therefore, this study may represent real-world practices of ER based on medical needs.\u003c/p\u003e \u003cp\u003eGiven the potentially life-threatening nature of ALC per se, it presents a complex challenge in the ER. Effective management requires vigilant medical staff, comprehensive history-taking, well-established medical protocols, appropriate diagnostic approaches, prompt assessments, and tailored interventions. The dynamic and continuous attribute of consciousness, coupled with the often elusive identification of underlying causes, amplifies the complexity of the research designs on ALC in the ER. The inconsistent definition associated with ALC in previous studies and real-world practice, including terms synonymous with loss of consciousness, impaired consciousness, mental change, and altered mental status, goes beyond a mere variety in terminology, signifying its nonspecific nature with diverse etiologies. In order to address these limitations, we reviewed 17,913 cases out of 583,353 ER visits to four university hospitals, spanning 2 years in both BC and AC, respectively. The outcomes, offering foundational insights into ALC in the ER, illuminate various facets of real-world clinical practice, covering demographic characteristics, etiology, dispositions from the ER, and post-hospitalization outcomes. To the best of our knowledge, this study includes the most extensive population in research related to ALC in the ER and marks the first investigation on ALC in the ER comparing BC and AC.\u003c/p\u003e \u003cp\u003eWhen stratifying age into 10-year intervals from the 20s, there was a decrease in the proportion of patients below 60. In contrast, those aged 60 and above showed an increment\u0026mdash;patients aged 70 and above constituted over fifty percent of the total, especially in AC. The mean ages reported in previous studies ranged from 49 to 69,[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] compatible with our study. Nevertheless, a closer look at previous studies shows that the mean age is higher in recent studies compared to earlier studies. The mean ages were reported as 49 and 45 in 2002 and in 2008, respectively [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Subsequently, Forsberg et al. and Xiao et al. reported 59 and 51 in 2009 and 2012,[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] respectively. Data from the late 2010s showed that the mean age reached the late 60s [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. While the proportion of sex varies from study to study, the age of ALC in the ER tends to increase.\u003c/p\u003e \u003cp\u003eThe overall length of stay in the ER was shortened in AC by approximately 2 hours, which suggests improved patient distribution and disposition from the ER in AC. There were about 4- and 6-hour reductions in Metabolic cause and Systemic infection, respectively. These two etiologies account for approximately 42% of the patients with ALC in the ER and mainly suggest non-surgical problems. There was no difference in vascular diseases such as C\u0026amp;V and Stroke, which implies that the same level of intervention protocol as BC was carried out in time. According to the opinion of the consortium members in this study, hospitalizations have increased while the number of transfers has decreased, leading to a reduction in the time required to make decisions about dispositions. In BC, patients with ALC attributed to Metabolic causes or Systemic infection could be transferred to another hospital when conservative management was only required. However, under COVID-19 guidelines in AC, early transfer became challenging, leading to an increased hospitalization rate. Consequently, patients with ALC experienced shorter stays in the ER, and the hospitalization rate increased, which resulted in a shorter ER stay time for ALC patients. In essence, changes in administration and healthcare delivery system facilitated earlier decisions for hospitalization, thereby reducing ER stay time.\u003c/p\u003e \u003cp\u003eIn AC, there was a decrease in the proportion of ICU admissions, while GW admissions showed a significant increase due to the abovementioned reasons. The leading etiology sent to the ICU was Stroke: The allocation of ICU involves issues regarding the distribution of limited medical resources. (i.e., the limited number of ICU beds). Moreover, it does not imply a decrease in critical patients with ALC requiring ICU management. This distribution analysis focuses on the increased hospitalization rate to either the ICU or GW for patients with ALC, alongside a decrease in transfer and an increase in death in the ER. The decreased transfer also represents herding behavior in the healthcare delivery system [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], while death in the ER implies death pending ICU admission. Consequently, we need alignment in the healthcare delivery system between the classes of hospitals and enhancement of bed turnover rates of ICU in university hospitals. Additional research and interventions are needed regarding the mortality linked to ALC caused by metabolic causes or systemic infections during ER stays, as indicated by this study's findings.\u003c/p\u003e \u003cp\u003eThe overall mortality in this study was 16.2%, amounting to 2908 deaths, with 1278 in ICU, 685 in GW, and 945 within the ER. The mortality rate for hospitalized patients is 19.1%. Mortality rates of GW and ICU were 13.5% and 24.8%, respectively, with higher mortality rates among those admitted to ICU (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). These results are consistent with previous studies, ranging from 7\u0026ndash;27% [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. It is nearly impossible to stratify the cause of death because of the myriad complications that may arise. Nonetheless, we observed that C\u0026amp;V had the highest mortality rate in BC, followed by Systemic infection. This pattern persisted in AC, but the Stroke and Metabolic cause became the third and fourth. In general medical disorders, an increase in mortality has already been reported in AC [\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Since a history of COVID-19 infection per se has been reported to be a risk factor for higher mortality [\u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e], the increased mortality in Metabolic cause, Systemic infection, Stroke, and undeterred were believed to be directly attributed to the impact of COVID-19. Previous studies of mortality in ER suggested that the causes of increased mortality included delayed access to healthcare services, misalignment of resource distribution, and overcrowding of ER in AC [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Regarding Toxic, according to the ALC-10 classification criteria, it encompasses ALCs caused by ingestion or inhalation of toxic materials (alcohol, insecticides ingestion, or adverse drug reactions), regardless of intent. It is well known that depression and suicide increased in AC [\u003cspan additionalcitationids=\"CR32 CR33 CR34\" citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Based on the authors' experience in the ER, there has been an increase in binge drinking or drug administration associated with feelings of hopelessness or suicidal intentions after the onset of COVID-19. Besides, there has been a tendency to transfer such cases to university hospitals in hospitals with limited resources because addressing toxic cases involves the exclusion of alternative causes. Consequently, we surmise that the increased mortality rate of Toxic is more likely a secondary effect of changes in the healthcare delivery system and the increase in psychological distress, such as \"long COVID.\"\u003c/p\u003e \u003cp\u003eIn the etiology classification, the numbers of Metabolic cause, Systemic infection, Toxic, C\u0026amp;V, and Psychiatric disorder have increased. Nevertheless, only systemic infections and C\u0026amp;V showed statistically significant increases in AC compared to BC. In contrast, there were several etiologies of a significant decrease in the proportion: Stroke, TBI, and Seizure. Notably, the number of patients remained similar despite the decline in proportions. It is reasonable to conclude that while the incidence of Stroke, TBI, and Seizure did not decrease, the number of cases involving Metabolic cause, Systemic infection, Toxic, C\u0026amp;V, and Psychiatric disorder increased, with Systemic infection and C\u0026amp;V showing particularly significant increases\u0026mdash;the only etiology of a significant decrease in the proportion as well as the number was CNS infection. The increased incidence of Systemic infection in AC resulted from the increased incidence of sepsis or septic shock associated with COVID-19 infection [\u003cspan additionalcitationids=\"CR37 CR38\" citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. Regarding C\u0026amp;V, it is well known that COVID-19 is associated with myocarditis, myocardial infarction, arrhythmia, and heart failure [\u003cspan additionalcitationids=\"CR41\" citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e], which could result in cardiogenic shock. In addition, recent studies reported that not only COVID-19 per se but also COVID-19 vaccination were associated with the risk of cardiogenic shock [\u003cspan additionalcitationids=\"CR44\" citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. This is another evidence to support the increased C\u0026amp;V in this study. ALC in the ER increased in AC, and the significant increase in the incidence of ALC by Systemic infection and C\u0026amp;V in AC would have been a direct impact of COVID-19.\u003c/p\u003e \u003cp\u003eIn many studies [\u003cspan additionalcitationids=\"CR5 CR6 CR7 CR8\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], the primary etiology of ALC in the ER has been identified as intracranial (e.g., neurological, stroke, seizure, dementia). However, our study demonstrated that the main etiologies of ALC in the ER were extra-cranial. This does not diminish the significance of intracranial etiology; instead, it emphasizes the need for a multidisciplinary approach to addressing ALC in the ER without underestimating intracranial causes. In addition, it is notable that Undetermined accounted for more than 7% of the total, while the unknown etiologies, so-called \"Others\" or \"Miscellaneous,\" did 3\u0026ndash;9% in previous studies [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The significant numbers suggest that the cause of ALC in the ER can remain inconclusive despite an intensive assessment lasting more than 10 hours and may require additional medical access. Undetermined encompassed unknown causes, two or more causes and not classified elsewhere in this study. It is widely acknowledged that diagnoses made in the ER are provisional, and distinguishing between multiple causes can be highly challenging [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]; however, Undetermined is a significant etiology classification with a mortality rate of as high as 16% in AC. Our consortium's discussed and agreed opinion is that Undetermined, i.e., the etiology of unknown, should be accepted as a characteristic of ALC in the ER. In the management of ALC in the ER, what we need in ALC in the ER is not a hasty name but an appropriate assessment and reasonable measure, even after discharge from the ER. Thus, additional medical assessments, including admission and multidisciplinary approaches, should be considered.\u003c/p\u003e \u003cp\u003eSeveral limitations merit consideration in interpreting the study findings. The retrospective nature of the study is an inherent bias. Second, a single ethnic background should be considered. Lastly, the interpretation should be contextualized within the healthcare landscape in South Korea. However, this study offers a comprehensive exploration of ALC in the ER, including the change of etiology, demographic shift, disposition, and prognosis based on data from approximately 18,000 subjects in 4 years. The observed shifts in ALC patterns between BC and AC indicate a discernible evolution in emergency care dynamics over time, ostensibly influenced by the COVID-19 pandemic. This suggests the imperative for sustained vigilance in organizing healthcare strategies that adapt to the dynamic healthcare landscape. Further prospective studies with continued data collection that can represent the healthcare environment for each center should be encouraged.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgement:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors wish to thank and acknowledge Soo-yeon Yoon for her invaluable work on data processing. This study was supported by a grant from Korean Neurological Association (KNA-22-SK-17).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eDisclosure of Conflict of Interest: \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no potential conflicts of interest to disclose.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Author Contributions\u003c/p\u003e\n\u003cp\u003eConceptualization: KT.K, DH.K\u003c/p\u003e\n\u003cp\u003eInvestigation, Data curation, Formal analysis, and Validation: All authors\u003c/p\u003e\n\u003cp\u003eProject administration: KT.K, DH.K., JA.P., JG.S.\u003c/p\u003e\n\u003cp\u003eVisualization: KT.K.\u003c/p\u003e\n\u003cp\u003eWriting\u0026mdash;original draft: KT.K.\u003c/p\u003e\n\u003cp\u003eWriting\u0026mdash;review \u0026amp; editing: All authors\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAmerican College of Emergency Physicians (1999) Clinical policy for the initial approach to patients presenting with altered mental status. 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Immun Inflamm Dis 11:e807. https://doi.org/10.1002/iid3.807\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Emergency room, Emergency medical services, Consciousness disorders, Neurologic manifestations, COVID-19","lastPublishedDoi":"10.21203/rs.3.rs-3987446/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3987446/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eNew-onset altered level of consciousness (ALC) is challenging in emergency rooms (ERs), requiring focused attention. The COVID-19 pandemic has impacted healthcare systems globally, influencing ER dynamics. This study compared ALC before (BC) and after (AC) the coronavirus disease 2019 outbreak, focusing on etiology, disposition, and outcomes. This was a retrospective, multicenter study of four university hospitals in charge of an area of about five million people in South Korea. All cases were reviewed within a consortium of board-certified faculties and compared between BC (February 2018 to January 2020) and AC (March 2021 to February 2023. We reviewed to find 17,913 patients who visited the ER due to ALC, of whom 7,988 and 9,925 were in BC and AC, respectively. The overall incidence of ALC in the ER was 3.1%, higher in AC (BC vs. AC, 2.5% vs. 3.7%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The most common etiology was Metabolic cause (24.8%), followed by Systemic infection (18.0%). Intracranial etiologies accounted for 29.7% of the total. Hospitalization rate increased from BC to AC (54.5\u0026ndash;59.3%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The overall mortality was 16.2%, and 5.3% of the patients with ALC died in the ER. ALCs dut to cardiogenic and vascular etiology had the highest mortality (26.8%). This study marks the first investigation on ALC in the ER comparing BC and AC.\u003c/p\u003e","manuscriptTitle":"Etiology and mortality of patients with altered level of consciousness in the emergency room: a multicenter analysis before and after the coronavirus disease 2019 outbreak","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-29 16:39:51","doi":"10.21203/rs.3.rs-3987446/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fc6c6f4a-0ee0-4056-a6a1-3e06b4910f71","owner":[],"postedDate":"April 29th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-11-28T20:48:29+00:00","versionOfRecord":[],"versionCreatedAt":"2024-04-29 16:39:51","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3987446","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3987446","identity":"rs-3987446","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}