Pattern of non-trauma emergency department resource utilization in older adults: An 8-year experience in Taiwan : Journal of the Chinese Medical Association

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Original Article

Pattern of non-trauma emergency department resource utilization in older adults: An 8-year experience in Taiwan

Chang, Julia Chia-Yua,b; Yuan, Zih-Hana; Lee, I-Hsina,c; Hsu, Teh-Fua,b,*; How, Chorng-Kuanga,b; Yen, David Hung-Tsanga,d

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Journal of the Chinese Medical Association: June 2018 - Volume 81 - Issue 6 - p 552-558
doi: 10.1016/j.jcma.2017.10.008


    1. Introduction

    Emergency departments (EDs) play an increasingly important role in the care of general populations, particularly the elderly. EDs provide important services to older adult patients, often serving as a point of entry to the healthcare system, providing after-hours care to those unable to access a primary care provider. The healthcare of aging populations requires more medical care and expenditure. Studies suggest that visits by older patients to ED differ from those by younger patients. Older patients are often more acutely ill than younger patients1–3 and are more likely to be hospitalized subsequent to their visits.1–4 A Canadian study on ED usage reported that of the 9.1% patients admitted after their ED visits, approximately half (47.1%) were aged ≥65 years.5 An US study reported that increased resource utilization by older adult patients during their ED visits is due to the increased number of laboratory tests, advanced imaging, and both ordinary ward and intensive care unit (ICU) admissions.6

    Several studies have described ED usage by older adult patients; however, few have focused on Taiwan, which will have the fourth largest increase in adult population aged ≥65 years between 2015 and 2030 (preceded by Cuba, Korea, and Hong Kong), as predicted by the United Nations.7 Based on our search of the English literature, we found that our study was the first to observe ED usage by older adult patients in Taiwan. A better understanding of ED usage and age-related comparisons will help in planning informed strategies to meet the healthcare needs of an aging population.

    In this study, we explored demographic changes in ED usage by adult patients aged ≥20 years from January 1, 2005 to December 31, 2012 in a tertiary care teaching medical center in northern Taiwan. We hypothesized that older adult patients utilized more ED resources due to higher number of ED visits, critically ill status upon presentation, and higher likelihood of hospitalization. We attempted to determine the realistic ED resource utilization in a rapidly aging country such as Taiwan during an 8-year period.

    2. Methods

    This is a retrospective, observational single-center cohort study conducted in the ED of Taipei Veterans General Hospital (TVGH), an urban medical center in Taipei, Taiwan, with an annual ED population of approximately 80,000 patients. We included adult patients aged ≥20 years who visited ED (for non-trauma reasons) from January 1, 2005 to December 31, 2012. The hospital's Institutional Review Board (IRB) approved the research protocol (IRB No. 2013–11–009BC) and waived the requirement of signing an informed consent.

    To collect raw data, informatics specialists used a structured search designed to detect all non-trauma patients aged ≥20 years from our electronic medical records database during the study period. We considered the following patient and ED visit characteristics: patient age, gender, Taiwan Triage and Acuity Scale (TTAS) levels,8 ordinary or ICU admission, and total medical cost. Before data extraction, raw data were debugged by the sorting and filtering technique to find missing data or outliers. Questionable results were checked and corrected by the informatics specialists. Due to uncorrectable data, a total of 3241 (0.73%) patients were excluded from final analysis.

    Patients' age was stratified by 10-year intervals: 20–29, 30–39, 40–49, 50–59, 60–69, 70–79, 80–89, and ≥90 years. Patients were divided into a high-acuity group (TTAS level 1 and level 2) and a low-acuity group (TTAS level 3, level 4, and level 5). The characteristics of the general population in metropolitan Taipei were obtained from the Department of Household Registration, Ministry of the Interior, Taiwan, Republic of China.9

    ED cost was defined as cost in ED before admission or discharge and included fees for registration, physician consultation, nursing care, laboratory tests, imaging [computed tomography (CT), magnetic resonance imaging, etc.], clinical procedures (endotracheal intubation, thoracostomy, thoracocentesis, etc.), and medication. We converted costs according to end-of-year exchange rates of the US dollar and the New Taiwan dollar (NTD), which are as follows for 2005 through 2012, respectively: NTD 32.89, NTD 32.59, NTD 32.50, NTD 33.04, NTD 32.00, NTD 29.17, NTD 30.31, and NTD 29.04.

    ED visits were characterized using standard descriptive statistics. Continuous variables were represented as mean and standard deviation (SD) with confidence interval (CI). Categorical variables were represented with number, percentage, and SD. Differences between groups were assessed using the Mann–Whitney U test for continuous data (not normally distributed) and the chi-square test for categorical data. Trend analyses of continuous variables (age and cost) were assessed using analysis of variance (ANOVA) with linear trend. Trend analyses of categorical variables (gender, age group, triage, and disposition) were assessed using chi-square tests with linear-by-linear association. All analyses were conducted using commercial software SPSS 16.0 (SPSS, Inc, Chicago, IL, USA). Statistical significance was set at 0.05.

    3. Results

    A total of 441,665 adult patients visited our ED during the 8-year study period for non-trauma reasons. The patient population mean age was 62 years, and 59.2% were men. Patients aged ≥70 years accounted for 45.2%. There was an overall 10.3% increase in ED usage from 53,490 patients in 2005 to 59,025 patients in 2012 (Table 1). There was an overall 9.2% increase in the metropolitan Taipei population from 5,081,947 inhabitants in 2005 to 5,551,014 inhabitants in 2012. The adjusted ED usage growth rate was 1.0%. The mean cost per ED visit was 229.2 United States dollar (USD), with a 16.9% increase from 211.1 USD in 2005 to 246.8 USD in 2012. Each decade of the younger population (aged 20–29, 30–39, 40–49, 50–59, and 60–69 years) contributed to approximately 10% (9.1%–13.2%) of the ED visits. Septuagenarians (aged 70–79 years) and octogenarians (aged 80–89 years) contributed to approximately 20% of ED visits (19.8% and 22.3%, respectively), which was twice compared with the contribution of the younger populations. Although nonagenarians (≥90 years) contributed to a mere 3.1% of ED visits during the study period, they increased more than twice in number, from 1.8% in 2005 to 4.6% in 2012. The age composition of adult ED visits and the general adult population was depicted in Table 2. The ratio of ED visits and general population of metropolitan Taipei stratified by age (normalized contributions to the ED) was 0.51 (20–29 years), 0.42 (30–39 years), and 0.50 (40–49 years). In contrast, older adult patients had much higher normalized contributions to ED: 3.56 (70–79 years), 8.34 (80–89 years), and 7.64 (≥90 years).

    Table 1:
    Characteristics of non-traumatic adult ED patients between 2005 and 2012.
    Table 2:
    Comparisons of percentage of general adult population of metropolitan Taipei and non-traumatic adult ED patients stratified by age between 2005 and 2012.

    Older adult patients required more ED resources, had higher acuity levels, and were more readily admitted to the ordinary ward and ICU compared with young adult patients (Table 3). Patients aged ≥90 years required almost twice as much ED resources per visit [adjusted risk ratio (aRR), 1.98] compared with patients aged 20–29 years. Acuity level also increased with increasing age, with the aRR of 70–79, 80–89, and ≥90 y/o being 1.96, 1.87, and 1.91, respectively. The risk of ICU admission in the age groups 40–49, 50–59, 70–79, and ≥90 years increased by 3-fold (aRR, 2.99), 4-fold (aRR, 4.09), >6-fold (aRR, 6.66), and almost 10-fold (aRR, 9.84), respectively, compared with that in the age group 20–29 years.

    Table 3:
    Comparisons of resources utilization of non-traumatic adult ED patients stratified by age between 2005 and 2012.

    The percentage of patients categorized under the high acuity group (TTAS level 1 and 2) increased with age, and reached a plateau after age >70–79 y/o (Fig. 1). The percentage of patients in the high-acuity group in the age groups 70–79, 80–89, and ≥90 years was 48.8, 46.6, and 47.6, respectively. The overall ED cost increased with increasing age. High-acuity levels were associated with higher ED cost across all the age groups (Fig. 2).

    Fig. 1.:
    The percentage of patients categorized under high acuity (TTAS level 1 and TTAS level 2) increased with age, and reached a plateau after age >70–79 years.
    Fig. 2.:
    Overall ED cost increased with age. High acuity levels (TTAS level 1 and TTAS level 2) were associated with higher ED cost across all age groups.

    The percentage of patients requiring admission increased with increasing age in both ordinary ward and ICU admissions (Fig. 3). Patients in the high-acuity group (TTAS level 1 and 2) had higher all admissions, including ordinary ward and ICU admissions, compared with patients in the low-acuity group (TTAS level 3, 4 and 5). The percentage of patients aged ≥90 years requiring ordinary ward and ICU admissions was 47.9 and 13.5, respectively. The risks of ICU admission increased by 3-, 4-, 6-, and 10-fold in the age groups 40–49, 50–59, 70–79, and ≥90 years, respectively, compared with that in the age group 20–29 years (Table 3). Despite being classified as low acuity, patients aged ≥90 years comprised 2.9% of ICU admissions, whereas patients ≥90 years in the high-acuity group comprised 25.1% of ICU admissions.

    Fig. 3.:
    The percentage of patients requiring admission increased with age in both ordinary ward and ICU admissions. Patients with high acuity (TTAS level 1 and TTAS level 2) had increased all admission, ordinary ward and ICU admissions compared to low acuity patients (TTAS level 3, TTAS level 4, and TTAS level 5).

    4. Discussion

    Our study shows that older adult patients are associated with higher proportions of ED visits, higher acuity levels, higher ED costs, and higher risks of admission to both the ordinary ward and ICU. Older adult patients have higher percentages of ED usage after normalizing to the percentage of their population compared with younger adult patients (Table 2). Septuagenarians (aged 70–79 years) and octogenarians (aged 80–89 years) have twice as many ED visits compared with the younger age groups. Our study shows high ED usage in the age group 70–79 years (aRR = 3.56), but ED usage truly peaked in the age group 80–89 years (aRR = 8.34), followed by the age group ≥90 years (aRR = 7.64) (Table 2). A similar increase in the ED usage was observed in the US6 and Canada.10 Studies in the US have revealed that adults aged ≥75 years had the highest ED visit rate, followed by infants aged <1 year, whereas studies in Ontario, Canada, have revealed that patients aged ≥75 years had high rates of ED visits.11–13

    4.1. The overall ED cost and ED resource utilization increased with increasing age (Fig. 1)

    Patients aged ≥90 years required almost twice as much ED resources per visit (aRR, 1.98) compared with those aged 20–29 years. The cost of ED visits increased by more than 50% (aRR, 1.61) in patients aged 60–69 years compared with those aged 20–29 years (Table 3). There were many factors contributing to the higher cost associated with older patients; more advanced imaging performed in older patients was one of them. Our study, conducted on the same ED population at the TVGH from 2005 to 2009, revealed that the CT utilization rate increased with increasing age. In fact, patients aged >65 years accounted for more than half of the total CT scans in ED (59.9%).14 We found that the older the patients, the higher the CT utilization rates, with 80 per 1000, 119 per 1000, 156 per 1000, 186 per 1000, and 193 per 1000 in patient age groups 20–34, 35–49, 50–64, 65–79, and >80 years, respectively.14 Moreover, CT costs contributed to more than one-third (36.3%) of the overall ED cost for non-trauma ED visits. The average ED cost for CT users increased by 3.10-fold compared with that for non-CT users;14 hence, the higher ED cost associated with older patients was partly attributable to the ready performance of advanced imaging in the elderly. A Canadian study conducted by Latham LP et al. on ED visits by older adults showed that almost half (49.8%) the visits involved diagnostic imaging, 62.1% involved lab work, and 30.8% involved consultation with other departments or services.10 This led to extra costs associated with advanced age in the form of advanced imaging, laboratory and urine testing, time-consuming care coordination, longer ED stays, and more-frequent hospital admissions.3,4,6,10

    4.2. Older adult patients were associated with higher acuity

    Almost 50% of patients older than 70 years were triaged under the high-acuity group (Fig. 1). The risk for high acuity increased with increasing age and dramatically increased in patients older than 70 years, where the aRR in the age groups of 70–79, 80–89, and ≥90 years were 1.96, 1.87, and 1.91, respectively (Table 3). A similar observation was made by Latham LP et al., where 74.2% of ED visits by older adult patients were triaged as “urgent or emergent” based on the Canadian Triage and Acuity Scale.10 Older adult patients often presented with high acuity because they are accompanied by multiple comorbid conditions, atypical presentations of common diseases, polypharmacy, and cognitive or functional decline.1,3,15,16 Presenting with more complex conditions, older adult patients also are at a higher risk for inappropriate or delayed evaluation due to undertriage at the ED entry.17,19,20 It is paramount, therefore, to perform systematic and thorough geriatric assessments for early identification of older adult populations at risk, particularly in countries predicted to have large changes in the percentage of older age populations.

    4.3. Patients in the high-acuity group require more ED resources through all age groups (Fig. 2)

    The high ED cost in patients in the high-acuity group can be explained by disease severity and critical conditions that warrant intense ED resources for resuscitation, advanced examinations, and subsequent definite treatments. The cost of standard equipment for patient monitoring and staff versus patient ratio in a resuscitation room also contributed to the high cost associated with patients in the high-acuity group. The proportion of patients in the high-acuity group reached a peak in patients aged ≥70 years (Fig. 1); however, this plateau was not observed in the overall ED cost (Fig. 2). The overall ED cost continued to increase with age despite the ceiling effect in acuity. This demonstrated ED cost increase was influenced by both high-acuity levels and increase in age.

    4.4. All admissions including ordinary ward and ICU admissions increased with increasing age (Fig. 3)

    A higher percentage of all admissions was observed in the high-acuity group across all the age groups; thus, the combination of old age and high acuity warranted either ordinary ward or even ICU admission. Despite being triaged under the low-acuity group, patients aged ≥90 years had an overall admission of 34.2% (Fig. 3A). Patients aged ≥90 years and with high acuity accounted for 25.1% of ICU admissions, whereas the same population with low acuity had an impressive 2.9% ICU admission rate (Fig. 3C). This suggests that 3% of patients aged ≥90 years initially triaged under the low-acuity group experienced an unexpected outcome and deteriorated to requiring ICU admission. Our findings were compatible with those of Latham LP et al. who reported that older adult patients were more likely to be admitted to the hospital as a result of their ED visits, leading to increases in median ED lengths of stay.10 A study by Mohd Mokhtar MA et al. also found that older adult patients are an independent predictor of hospital admission.4

    Our study includes a much higher proportion of older adult patients compared with previous studies. Our study comprises 441,665 adult ED visits during an 8-year period, with 45.2% of patients aged >70 years representing a larger, older population. Latham LP et al.10 included 158,344 ED visits with 21.8% of patients aged >65 years. Pines JM et al.6 described an ED usage of 104.6 million in 2001 and 82.8 million in 2009, with 18.9% and 19.8% of patients aged >65 years, respectively. The reasons for the high numbers of older adult patients in our ED were not evaluated in this study. We propose a few contributing factors, including preference and higher confidence in university hospitals such as TVGH, the lack of a proper national system by general practitioners to restrict unnecessary ED visits, and easy access to EDs in a metropolis such as Taipei. Older patients often consider EDs in a fully equipped hospital to better meet their complex healthcare needs. Moreover, TVGH is a tertiary care medical center in which critical patients are referred from other hospitals for definitive care. These referred patients may happen to be sicker and older.

    4.5. Limitations

    Our study has numerous limitations. First, this study is retrospective and thus is subjected to limitations that retrospective studies face. Second, this study was conducted in a single urban medical center and thus the results may not be generalizable to other hospitals. Third, because TVGH is a veterans' general hospital, it may include higher proportions of veteran patients. The study, however, did not distinguish between veterans and non-veterans. No data were available to support how the veteran population contributed to our study population. Our study addressed only direct medical costs in ED and did not include costs of admission into ordinary ward or ICUs. Finally, our analysis was limited to the ED visit, with no added information on patient comorbidities, functional status, frailty, or polypharmacy, which could also influence ED resource use and outcome.21 Many studies have demonstrated that older adult patients are at a risk of being undertriaged in ED,17–20 and our study may also have inaccurately underestimated the critical condition of older adult patients.

    In conclusion, with an ever-increasing aging population worldwide, medical expenditure is expected to increase significantly in the future. Our study showed that older adult patients are associated with more ED visits, higher acuity, higher ED costs, and higher risks for admission to the ordinary ward or ICU. Aging populations will overwhelm our emergency care system in the near future if these systems are not redesigned to meet the complex needs of older adult patients. An understanding of ED visits by older adult patients is essential for strategic planning and modification of the current emergency system to meet the imminent and growing healthcare needs of older adult patients.


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    Emergency department; Health resource; Hospital costs; Patient acuity

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