Radiology

Comparing rates of skull fractures in female versus male geriatric patients who sustain head injuries

a b s t r a c t

Background: Head trauma is the leading cause of serious injury in the older adult population with Skull fractures as a serious reported outcome. This study aims to evaluate the role of sex in the risk of skull fracture in patients over the age of 65.

Methods: A prospective cohort study was conducted at two level-one trauma centers, serving a population of 360,000 geriatric residents. Over a year-long period, consecutive patients aged 65 years and older who presented with blunt head injury were included. Patients who did not receive Head CT imaging were excluded. The primary outcome was rate of skull fracture due to the acute trauma, compared by sex. Additional factors examined included Patient race/ethnicity and mechanism of injury.

Results: Among 5402 patients enrolled, 3010 (56%) were female and 2392 (44%) were male. 4612 (85%) of the head injuries sustained were due to falls, and 4536 (90%) of all subjects were Caucasian. Overall, 199 patients (3.7%) sustained skull fractures. Males had a significantly greater rate of skull fracture when compared to females (4.6% vs 3.0%, OR 1.5, 95% CI: 1.2-2.1, p = 0.002). This trend was also seen across race/ethnicity and mechanism of injury.

Conclusions: Older males were found to have a higher rate of skull fractures compared to females after sustaining Blunt head trauma, mostly due to falls.

(C) 2023

  1. Introduction

In the United States, 16.8% of the population or >55 million people are aged 65 years or older [1]. As the population continues to grow older and stay active for longer, the percentage of geriatric traumatic in- juries has subsequently increased [2]. With the increase of traumatic in- jury among the geriatric community, it is important to reassess the consequences of these injuries and identify at-risk populations. The 2016 National Trauma Database annual report showed that persons age 65 or older accounted for 55% of all falls and females account for 58% of those [3]. A study analyzing 4544 patients aged 65 or older who presented to the ED with injuries due to falling or car accident,

* Corresponding author at: Florida Atlantic University at Bethesda Health, Department of Emergency Medicine, GME Suite, Lower Level, 2815 South Seacrest Blvd, Boynton Beach, FL 33435, USA.

E-mail addresses: [email protected] (S.M. Alter), [email protected] (M.R. Gonzalez), [email protected] (J.J. Solano), [email protected] (L.M. Clayton), [email protected] (P.G. Hughes), [email protected] (R.D. Shih).

found that the most common type of trauma was head injury and, over- all, geriatric females presented with head injury more often than geriat- ric males (1431 total cases: 55% female, 45% male) [4]. A retrospective study of 181 Geriatric patients with Facial fractures found that females were more frequently affected compared to males (55% vs 45%, respec- tively) [5]. Moreover, one study found there is an increased risk of facial fracture among females 65 years or older, particularly of Caucasian or Asian descent. A comparison of sex among the Geriatric population showed females had an increased facial fracture predilection (15%) compared to males (14%). Females 65 years or older had an increased risk of facial fracture (15%) relative to those younger (12.5%) [6]. Unfor- tunately, no studies have been completed regarding skull fracture prev- alence due to head injury in this population.

Due to geriatric female’s increased prevalence of falls and facial frac- tures, it is important to determine if this population also has an in- creased risk of skull fractures secondary to head injury. Currently, there is an overall lack of research regarding head injury management guidelines among the geriatric population [7]. Specifically, there is lim- ited research regarding morbidity and mortality in the geriatric popula- tion secondary to a skull fracture. Therefore, it is important to determine

https://doi.org/10.1016/j.ajem.2022.12.044

0735-6757/(C) 2023

risk factors and identify at-risk populations. This study intends to deter- mine the risk of skull fractures secondary to head trauma in female patients compared to male patients, by prospectively evaluating all per- sons who presented with head trauma at two emergency departments.

  1. Materials and methods
    1. Study design

This is a cohort study of patients who presented to the emergency departments (ED) of two level-one trauma centers in a county serving southeast Florida. These facilities are the only trauma centers serving the county. Both EDs have a combined total annual volume of 119,000. Emergency medical services (EMS) in these hospital catch- ment areas follow Trauma activation protocols based on the CDC field triage of Injured Patients guidelines. The study was approved by the institutional review board of the hospitals’ affiliated university.

    1. Selection of participants

The study enrolled participants from August 2019 to August 2020. Criteria for inclusion consisted of patients who were 65 years or older, presented with blunt head trauma, and had a head CT performed. Exclu- sion criteria were patients who were transferred from another hospital due to need for inpatient trauma management, patients with penetrat- ing injuries, and patients with head trauma who did not have a CT per- formed. The study included patients who presented to the ED (seen by ED physician only) or who presented as a trauma activation by EMS (seen by ED and trauma physicians). Daily, patients with an ICD-10 code indicative of head injury (beginning with S00-S09) and patients that had a head CT in the ED were screened for study enrollment by trained research assistants. The screening included a chart review of physician notes to recognize head trauma or suspected head trauma. Suspected head trauma or head trauma that did not meet study criteria were reviewed by a physician investigator to ensure screening accuracy.

    1. Measurements

A chart review was performed by research assistants for all enrolled participants and the following information was obtained: sex, race, eth- nicity, mechanism of injury, and initial head CT results. Sex, race, and ethnicity variables were self-reported by the patients to the hospital registrar. Mechanism of injury was determined from the ED physician note and grouped into assault, bicycle accident, blunt injury, fall, motor vehicle accident, Motorcycle accident, pedestrian stuck, and su- perficial injury. Head CT reading was obtained from the final report as written by an attending radiologist not involved with the study, and classified as positive or negative for acute fracture. Data were collected and entered in the REDCap database system with real-time parameter validation.

    1. Outcomes

The primary study outcome was acute skull fracture diagnosed on initial head CT imaging performed after patient arrival at the hospital. This included fractures of cranial bones and facial bones. Any question- able findings were adjudicated by the study’s physician investigators.

    1. Analysis

Rate of skull fracture diagnosed by CT was compared between fe- male and male patients using odds ratios. In addition, rate of skull frac- ture by sex was further stratified by mechanism of injury and race/ ethnicity. Analyses were performed using SPSS version 29.0 (IBM Cor- poration, Armonk, NY USA) with statistical significance set at p < 0.05.

  1. Results

From August 2019 to August 2020, 5402 geriatric patients were en- rolled in the study. The patients were predominantly female: 3010 fe- males (56%) and 2392 males (44%). Both females and males had a similar mean age, 82.8 (SD 8.7) and 81.1 (SD 8.7) years, respectively. Among both females and males, falls were the predominant mechanism of injury: 85% (4612) of injuries overall, 88% (2646) of female injuries, and 82% (1966) of male injuries. Regarding ethnicity and race, individ- uals who identified as Caucasian made up 90% (4536) of patients, African American individuals made up 5% (266) of patients, Hispanic in- dividuals made up 4% (209) of patients, and individuals classified as other made up 1% (52) of patients. Ethnicity and race were unknown in 339 patients.

Overall, 90 females (3.0%) and 109 males (4.6%) were diagnosed with skull fractures. This was found to be a significant difference, with males having more fractures than females (OR 1.5, 95% CI: 1.2 to 2.1, p = 0.002). When analyzing skull fractures by sex in relation to mech- anism of injury, males had higher rates of skull fractures for all mecha- nisms, though only assaults were statistically significant (Table 1). No females had any skull fractures with mechanisms of assault, bicycle ac- cident, blunt injury, motorcycle accident, pedestrian struck, or superfi- cial injury. Odds ratios for males having a skull fracture were calculated for fall (OR 1.3, 95% CI: 1.0 to 1.8, p = 0.061) and motor vehi- cle crash (OR 3.1, 95% CI: 0.8 to 11.8, p = 0.087). Regarding ethnicity and race, a similar trend was seen that males of all races tended to have a higher rate of skull fractures than females (Table 2); however, this was only significant for Caucasians (OR 1.7, 95% CI: 1.2-2.3, p = 0.002).

  1. Discussion

When comparing geriatric Males and females, males had a signifi- cantly increased incidence of skull fracture secondary to head trauma. This outcome was unexpected, as previous literature indicated the fe- males being more susceptible to facial fractures [5,6]. Other studies have compared the skull cortical thickness, finding older females had a significantly greater reduction of thickness in the occipital, frontal, and parietal bones than males [8]. In geriatric males, there was an in- crease in cortical thickness, although it was not significant [8]. Regard- less, our study found that males had a higher prevalence compared to females.

Relating to patient race, we found similar trends between Cauca- sians, African Americans, and Hispanics, with males having greater rates of skull fractures than females. However, the results were only sta- tistically significant for Caucasians. This can likely be explained by Cau- casians making up the majority of patients in the study (90%), combined with the low rates of skull fractures overall (4%), resulting in few non- Caucasians with skull fractures.

For each mechanism of injury, males had greater rates of skull frac- ture than females, though many were not statically significant. This may be due to the low frequency of patients with mechanisms other than fall and motor vehicle accidents, and low numbers of skull frac- tures in the study. Perhaps an even larger study, over more than a one-year period or involving additional hospitals, would have achieved statistical significance.

One purposed theory of why males had greater rates of skull frac-

tures than females involves the specific mechanism of injury. Males disproportionally presenting to the ED for “high impact” head injuries (i.e. motorcycle or bicycle accidents) that could explain the prevalence of skull fracture. More males with these mechanisms causing higher rates of skull fractures could have skewed the overall results. Review of the data, however, revealed that ground level falls was the mecha- nism of injury for 85% of all patients, was similar between males (82%) and females (88%), and accounted for 165 of 199 (83%) skull fractures

Table 1

Mechanism of injury in relation to sex and skull fracture, n (%).

Skull fractures

Mechanism of Injury

Total

Female

Male

Total

Female

Male

OR (95% CI)

p

Assault

34

16 (47%)

18 (53%)

4 (12%)

0 (0%)

4 (22%)

0.045

Bicycle accident

44

8 (18%)

36 (82%)

6 (14%)

0 (0%)

6 (17%)

0.214

Blunt injury to head

66

32 (48%)

34 (52%)

2 (3%)

0 (0%)

2 (6%)

0.164

Fall

4612

2646 (57%)

1966 (43%)

165 (4%)

83 (3%)

82 (4%)

1.3 (1.0-1.8)

0.061

Motor vehicle accident

312

164 (53%)

148 (47%)

11 (4%)

3 (2%)

8 (5%)

3.1 (0.8-11.8)

0.087

Motorcycle accident

27

7 (26%)

20 (74%)

2 (7%)

0 (0%)

2 (10%)

0.385

Pedestrian struck

34

11 (32%)

23 (68%)

1 (3%)

0 (0%)

1 (4%)

0.483

Superficial injury

2

1 (50%)

1 (50%)

0 (0%)

0 (0%)

0 (0%)

Total?

5402

3010 (56%)

2392 (44%)

199 (4%)

90 (3%)

109 (5%)

1.5 (1.2-2.1)

0.002

* includes participants with missing mechanism of injury data.

Table 2

Race in relation to sex and skull fracture, n (%).

Skull fractures

Race

Total

Female

Male

Total

Female

Male

OR (95% CI)

p

Caucasian

4536

2538 (56%)

1998 (44%)

155 (3%)

68 (3%)

87 (4%)

1.7 (1.2-2.3)

0.002

African American

266

140 (53%)

126 (47%)

9 (3%)

2 (1%)

7 (6%)

4.1 (0.8-19.9)

0.063

Hispanic

209

131 (63%)

78 (37%)

13 (6%)

5 (4%)

8 (10%)

2.9 (0.9-9.1)

0.062

Other

52

27 (52%)

25 (48%)

2 (4%)

1 (4%)

1 (4%)

1.1 (0.1-18.3)

0.956

Total?

5402

3010 (56%)

2392 (44%)

199 (4%)

90 (3%)

109 (5%)

1.5 (1.2-2.1)

0.002

* includes participants with missing race and ethnicity data.

in this study. This data makes the high impact head injury theory less likely.

Still, one explanation for the increased male prevalence could be found among the fall patients themselves. A retrospective case review evaluated 282 patients presenting to an Australian trauma center due to non-ground level falls. Among the 282 patients, 91% were male. Thirteen deaths were records and ladders were implicated in seven [9]. This case review points to the high-risk behavior and “do it yourself”/ home renovations activity among the aging popula- tion, particularly males, as a possibly reason for their findings. Al- though not analyzed in our study, determining the prevalence of ground-level falls versus non-ground level falls among patients pre- senting with skull fracture might provide an explanation for the higher prevalence among the male population.

As falls caused the greatest number of head injuries and subsequent skull fractures, fall prevention may be an important intervention to con- sider in reducing morbidity. Although fall prevention education can be addressed in the Primary care setting or at assisted living facilities, pre- vious studies show that few EDs provide fall prevention education [10,11]. The ED may represent an educational opportunity with patients to prevent future morbidity and mortality from falls [11].

One study limitation involved the broad classifications of skull frac- ture. The specific type of bony fracture, whether cranial or facial, was not recorded. In a future study, classification of skull fracture locations may provide additional useful information. Another limitation of this study is that diagnosis of osteoporosis was not a collected variable. This could be a confounding variable, along with whether patients may have been taking vitamin D. However, as females are more likely to have osteoporosis, factoring osteoporosis might even widen the gap with males. Furthermore, males overall may have been less healthy with more co-morbidities, making them at increased risk for fractures. Another limitation of this study is that fall, the most prominent mecha- nism of injury, was not divided by ground-level and non-ground level. Males may have sustained more falls from greater heights. In a future study, further classification of falls may provide additional useful infor- mation in regard to skull fracture prevalence. Finally, the findings may only be representative of the geographic region in which the study has been performed. The demographic characteristics of geriatric patients

in southeast Florida may differ from other parts of the country, thus lim- iting the generalizability of the results.

  1. Conclusions

Older males were found to have a higher rate of skull fractures com- pared to females after sustaining head trauma, mostly due to falls. Over- all, the high incidence of head injury and subsequent skull fracture due to falls is a cause for concern and brings to light the importance of fall prevention as our aging population continues living active lifestyles.

Meetings

This research was presented at the 2020 Symposium by the Sea, held virtually from August 25-28, 2020.

Funding

This research was funded by a grant from the Florida Medical Mal- practice Joint Underwriting Association.

CRediT authorship contribution statement

Scott M. Alter: Writing – review & editing, Writing – original draft, Validation, Supervision, Project administration, Methodology, Investi- gation, Funding acquisition, Formal analysis, Data curation, Conceptual- ization. Michelly R. Gonzalez: Writing – review & editing, Writing – original draft, Conceptualization. Joshua J. Solano: Writing – review & editing, Validation, Supervision, Methodology, Investigation, Funding acquisition, Data curation, Conceptualization. Lisa M. Clayton: Writing – review & editing, Methodology, Investigation, Conceptualization. Patrick G. Hughes: Writing – review & editing, Methodology, Investiga- tion, Conceptualization. Richard D. Shih: Writing – review & editing, Validation, Supervision, Project administration, Methodology, Investi- gation, Funding acquisition, Conceptualization.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influ- ence the work reported in this paper

Acknowledgements

None.

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