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 Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 52  |  Issue : 2  |  Page : 39-44

Geriatric trauma: A population-based study


1 Department of Surgery, Taipei City Hospital, Taipei, Taiwan
2 Department of Emergency Medicine, Taipei City Hospital, Taipei, Taiwan

Date of Submission30-Apr-2018
Date of Decision21-May-2018
Date of Acceptance18-Nov-2018
Date of Web Publication18-Apr-2019

Correspondence Address:
Dr. Li-Chien Chien
No. 33, Sec. 2, Chuang-Hwa Road, Taipei City, 10062
Taiwan
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/fjs.fjs_44_18

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  Abstract 

Background: Geriatric trauma demands attention in aging societies. The trauma hospitalization rate gradually increases in elderly populations because they are more vulnerable to accidental injuries. High trauma admission rates among elderly groups led to further research about injury patterns and outcomes. We hope to understand more about the demographic patterns and mortality rate of geriatric trauma.
Methods: Information about all injured in-hospital patients ≥64 years was retrieved from a claims dataset from 2007 to 2008 from the Bureau of National Health Insurance in Taiwan. Statistical analyses were conducted on the population-based dataset to discover the incidence, mortality rate, percentage of chronic illness, and associations among variables such as age group, gender, injury mechanism, injury severity, and mortality.
Results: A total of 134,024 patients (28.2% of total inpatients' admissions) ≥64 years were admitted in 2007 and 2008; 45.0% were male patients, and 43.9% were rural residents. These resulted in 4120 deaths. Nearly 40.0% of patients had at least one chronic illness. Diabetes mellitus was the most common comorbidity (20.2%). Injury was most commonly caused by falls on the same level, followed by motorcycle accidents. A higher mortality rate was observed in the subgroup with higher injury severity scores. Logistic regression showed that the mortality rate was significantly higher in subgroups comprising patients aged 75–84 and >84 years, with higher Charlson index, and with mechanisms such as pedestrians hit by vehicles or falls from height.
Conclusion: High trauma hospitalization rates among elderly people can be reduced. Choosing a target population for injury prevention policy is required to reduce the geriatric trauma hospitalization rate. A regionalized trauma system providing the elderly population with optimal trauma care is mandatory.

Keywords: Fall prevention, geriatric trauma, mechanism of injury, mortality, trauma admission rate


How to cite this article:
Chen SS, Chien LC. Geriatric trauma: A population-based study. Formos J Surg 2019;52:39-44

How to cite this URL:
Chen SS, Chien LC. Geriatric trauma: A population-based study. Formos J Surg [serial online] 2019 [cited 2019 Nov 19];52:39-44. Available from: http://www.e-fjs.org/text.asp?2019/52/2/39/256532


  Introduction Top


Although injury has been neglected by many people, it is still a severe public health problem in many countries and is responsible for 9% of the world's deaths (more than five million deaths each year).[1] Mortalities caused by human immune-deficiency virus, tuberculosis, and malaria combined comprise less than three-fifths of those from trauma.[1] Among people aged 1–44 years, accidental injuries were the leading cause of deaths in the United States in 2010; they were also the ninth leading cause of deaths among people older than 64.[2] The effect of geriatric trauma on an aging society is more severe.[3],[4],[5] Injuries are commonly caused by falls. In the United States, falls are the leading cause of trauma from brain injury among people aged ≥65 years, and 25% of them fall every year.[6] However, these statistics are taken from studies conducted in Western countries, and no population-based information exists about in-hospital geriatric trauma and mortality rates. Moreover, demographic data regarding geriatric trauma patients, distribution of injury severity score (ISS), comorbidity, and the risk effect on mortality have not been well studied in Taiwan epidemiologically. The Taiwan National Health Insurance (NHI) Act was passed in 1994, and the Bureau of NHI was subsequently established to administrate the NHI system. NHI coverage rate was over 98% in 2008, and its claims data provide a population-based consensus-like databank. A previous study indicated that the trauma hospitalization rates increase with age. The percentage of people aged over 64 years in the total population is 10.4%; however, the percentage of trauma in-hospital patients is 28.1% among the total trauma admissions.[7] Compared with the general population in the United States, extremely high trauma admission rates are noted in two age groups. In the 65–84-year age group, the rate is 2549.1/100,000 population, and in the ≥85-year age group, the rate is 5379.1/100,000 population. This rate is 5.4 times higher than that in the young population group (15–24 years), which constituted the highest rate among people younger than 65 years.[7] The high admission rates contradict the traditional concept that trauma is considered a young person's disease. To better understand the epidemiological information, we analyzed the outcomes of all elderly patients admitted for injuries during 2007 and 2008, and all claims data were investigated for these 2 years.


  Materials and Methods Top


Numerous studies are based on the Taiwan NHI databank and have disclosed trauma-related epidemiological information.[8],[9],[10],[11],[12] A population-based study including all NHI trauma hospitalizations discharged between January 1, 2007, and December 31, 2008, investigated the characteristics of elderly patients that suffered trauma. A trauma admission is defined as claims data coded with at least one International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis between 800.00 and 959.99, except 905.00–909.99, 930.00–939.99, and 958. This NHI dataset, including the patients' demographics, residence, and the characteristics of treating hospitals, was analyzed to understand the incidence, mortality rate, and risk factors such as gender, age, distribution of residency, associated injuries, comorbidity, and mortality. The patients were stratified into three age groups as follows: 65–74, 75–84, and >84 years. The patients' area of residency was classified into two groups as follows: urban (including suburban) and rural areas. Preexisting conditions (PECs) were defined as medical comorbidities of injured patients who were diagnosed and recorded with ICD-9-CM codes in the same admission data file.[13] According to Charlson's study in 1987, 17 diseases are included in the formula for calculating the Charlson's index.[14] The patients are classified into four levels according to their Charlson index as follows: 0, 1, 2, and more than 2.

The abbreviated injury scale (AIS) and its revisions are useful and reliable tools for assessing injury severity, and they have been accepted by trauma care providers and researchers since their development.[15],[16] One of the most notable functions is ISS, which has become the most widely applied anatomic scoring system for injury severity in the world.[17] However, acquiring detailed injury data for the AIS are resource-intensive, and AIS scores are not routinely assessed or recorded in datasets. Moreover, ICD-9-CM codes are included in almost all administrative datasets after the 1980s and represent patient diagnoses. Computerized mapping methods that use the ICD-9-CM codes to obtain ISSs such as the AIS are a great achievement.[17] A computerized mapping system, ICDMAP, for converting injury-related ICD-9-CM rubrics into AIS scores was proposed by MacKenzie et al. in 1989, and their results have been verified.[17] ICDMAP has been refined over the years and has been used in several large or population-based studies to classify severity using ICD-9-CM codes.[18],[19] This study applied ICDMAP to the dataset and derived severity scores for each injury diagnosis. Subsequently, ICD/ISS was produced by this ICD mapping software for each admission.

Using the ICD-9-CM E-codes, we can classify the mechanisms of injury; the number after the decimal point of the E-codes indicates specific mechanisms. The patient is classified into either the driver or passenger in a motor vehicle traffic accident if the number after the decimal point is zero or one, respectively (e.g., E811.0, E811.1, E812.0, or E812.1). The patient is classified as a motorcycle rider or passenger injured in a traffic accident if the number is two or three, respectively (e.g., E811.2, E811.3, E812.2, or E812.3). The patient is classified as having an injury of an unspecified nature in a motor vehicle traffic accident if the number after the decimal point is nine (e.g., E811.9 and E812.9).

Statistical analysis

We compared the percentages of gender, four categories of monthly income, four categories of PEC, four categories of ICD/ISS, and mortality rates. Differences in proportions among these three levels of care (medical center [MC], regional hospital [RH], and local hospital [LH]) were evaluated using a Chi-square test. Mean, median, and standard deviation of continuous variables, such as age, monthly income, Charlson index, and ICD/ISS, were analyzed through ANOVA to understand the difference among these three types of hospital (i.e., MC, RH, and LH). Binary logistic regression techniques were used to understand the relative contribution of multiple risk factors on mortality. The relative odds (ROs) of deaths were analyzed using binary logistic regression through the backward conditional stepwise method.

The statistical significance was set at P < 0.05. The Institutional Review Board approval was waived because this study involved secondary anonymous data analysis of a well-encrypted database.

Ethics approval and consent to participate

Ethical approval was granted from National Yang-Ming University Hospital because this dataset is anonymous, and informed consent was waived by the Institutional Review Board. No conflict of interest is disclosed.


  Results Top


Throughout 2007 and 2008, among the total admissions, there were 134,024 patients' admissions caused by injuries and the patients were aged ≥65 years. Of 134,024 patients, 60,281 were men (45.0%). The average patient age was 76.7 ± 7.5 years (65–109 years). Patients' demographics are summarized in [Table 1], which includes the percentage of chronic diseases and three classifications of the Charlson index. A total of 58,873 patients (43.9%) resided in rural areas. Diabetes mellitus was the most prevalent chronic illness. Distributions of injury mechanisms and the four groups of ICD/ISS are exhibited in [Table 2]. Among the admissions, falls on the same level were the most common cause of injury (52,725 cases, 39.3%), and the second most common cause was motorcycle accidents (13,514 cases, 10.1%). The injury mechanisms, however, were not mentioned in 35,063 cases (26.2%). A total of 5108 cases (3.8%) were recorded as traffic accidents with no details provided. Overall, the mortality rate was 3.1%, and the median length of stay was 6 days (the 25th and 75th percentile were 4 and 10 days). Severe anatomic injury was defined as AIS score ≥3. Lower limb injury was the most common (29.1%) among the geriatric population. Femur neck fractures were found in 31,378 patient admissions (23.4%). The second and third most common injuries were spinal fractures (13,759 admissions, 10.3%) and head injuries (10,130 admissions, 7.6%), respectively. However, severe burns (17.3%), head injury (14.6%), and abdominal injury (14.7%) were associated with a higher percentage of death outcomes. A crosstable of the age groups, ICD/ISS severity groups, and the mortality rates in each subgroup are summarized in [Table 3].
Table 1: Demographic statistics for trauma patients older than 64 years

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Table 2: Injury characteristics, treatment places, and outcomes

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Table 3: Distribution of patient mortality by age and International Classification of Disease/injury severity score

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The relationship between mortality risk and various factors was analyzed using binary logistic regression through the backward conditional stepwise method. After the deletion of some factors (residency, ownership, and level of hospital), the results are summarized in [Table 4]. Several factors significantly increased the risk of mortality, such as gender, age (>74 years), higher Charlson index, pedestrians hit by car, and falls from a height. Taking people aged 18–64 years as references, the ROs for patients aged over 64 years was 2.48 (95% confidence interval, 2.35–2.63).
Table 4: Relative odds of risk factors for in-hospital mortality for elderly injured patients

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  Discussion Top


Trauma is presumed to be a young person's disease. However, we found a higher hospitalization rate among elderly groups, and geriatric trauma deserves more attention in aging societies. According to a report, the percentage of population aged older than 65 years will increase from 14% to 25% before 2030.[20] Another report indicated similar findings.[21] Among the US population, the percentage of people aged 65 years and older will increase from 13% in 2010 to 22% in 2020.[21] The number of injured, aged patients increases gradually because aged people presently are more active and mobile than those in the past. The elderly population is more vulnerable to accidental injuries. According to a previous study, trauma hospitalization rates increase with age. The percentage of people over 64 years in the total population is 10.4%; however, the percentage of trauma in-hospital patients is 28.1% among the total trauma admissions.[7] Increased trauma admissions among elderly people indicated an extremely high incidence rate among older groups (2549.1/100,000 people aged 65–84 years and 5379.1/100,000 people older than 84 years). The incidence rate of the patient group ≥85 years was five times more than that of the patient group aged 15–24. The study discovered some interesting findings regarding geriatric trauma. These findings will be helpful for future works regarding prevention.

First, the trauma admission rate is extremely high in the elderly population, with a higher mortality rate. This mortality rate is higher than average and comprises 53.9% of total in-hospital trauma mortalities. According to Chien's study, to address the high incidence of geriatric trauma, researchers should pay more attention and resources should be directed toward specific prevention programs focusing on the elderly population.[7] Among the total population, motorcycle accidents are the most common cause of injury (20.1%), and falls on the same level are the second most common cause (19.1%).[7] However, among the elderly population, 39.3% of admissions were caused by falls on the same level, which was extremely high. Falls are preventable and caused huge losses in modern society.[22],[23],[24] In this study, falls on the same level caused more deaths than traffic accidents. Focusing on geriatric trauma, the government should divert more resources toward fall prevention because of its severe effect on our society.[25]

Residence of patients did not affect the outcomes significantly here. One explanation is that the universal coverage of NHI ameliorated the disparities between the rural and urban areas. The other possibility is the limitation of the claims data. Some rural patients likely did not reach hospitals alive. Of the admissions studied, 26.2% were recorded with the mechanism of injury; these data may be used for conducting quality assurance in the future. The insufficient trauma data in Taiwan impeded the development of academic research on trauma care in Taiwan.


  Conclusion Top


This population-based study focusing on elderly patients with various injuries that are fully covered by NHI discloses the extremely high incidence and mortality rates of geriatric trauma and other related information about the associated risk factors. A national trauma databank in Taiwan, like that in other modern developed societies (e.g., the United States and Japan), is essential for understanding the nature and the incidence of geriatric traumas. Registries and a national trauma databank sponsored and maintained by government resources are essential for improving the quality of trauma care in the future.[26] Further studies focusing on geriatric trauma are mandatory.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

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  [Table 1], [Table 2], [Table 3], [Table 4]



 

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