- Email: [email protected]
Jaw fractures in the indigenous and non-indigenous populations of Western Australia: 1999–2003
Int. J. Oral Maxillofac. Surg. 2006; 35: 658–662 doi:10.1016/j.ijom.2006.01.019, available online at http://www.sciencedirect.com
Evidence-Based Therapy Trauma
Jaw fractures in the indigenous and non-indigenous populations of Western Australia: 1999–2003
E. Kruger, K. Smith, M. Tennant The Centre for Rural and Remote Oral Health, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
E. Kruger, K. Smith, M. Tennant: Jaw fractures in the indigenous and nonindigenous populations of Western Australia: 1999–2003. Int. J. Oral Maxillofac. Surg. 2006; 35: 658–662. # 2006 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. Little data exist on the analysis of jaw fractures in Australia, and none in Western Australia. This study was a retrospective analysis of all hospitalizations for jaw fractures in Western Australia between the years 1999–2000 and 2002–2003. The aims were to determine the incidence, distribution between males and females, different age groups, aboriginal and non-aboriginal groups, and rural and urban populations. The economic impact of jaw fracture hospitalizations was also determined. Males were more likely (80.4%) than females to be admitted for a jaw fracture. Fractures of the mandible were more common (61.9%) than maxillary fractures (38.1%). Aboriginal persons had nearly 10 times more hospitalization rate than that of non-aboriginal persons. Fracture rates were significantly (P < 0.05) higher in rural (61.9 per 100,000) than in urban areas. Over the 4-year study period the total costs for all jaw fracture hospitalizations exceeded US$ 7.6 million. This study clearly indicates the burden of jaw fractures on the Western Australian population, in terms of physical and economic impact.
Injuries to the soft tissue and bony skeleton of the face constitute a high percentage of all traumatic admissions to Emergency Departments22. The incidence and aetiology of maxillofacial fractures vary widely between different countries as a result of various contributing factors, such as age, gender, the environment and the socioeconomic status and culture of the patient. The causes and risk factors for fractures differ between countries, with motor vehicle accidents and assault being the most 0901-5027/070658 + 05 $30.00/0
common. Previous research also indicates a relationship between alcohol and substance abuse and facial injuries15,18. In some countries sporting injuries are also a common cause of jaw fractures5,19,21. Seasonal analysis indicates that most maxillofacial trauma occurs in summer7,8,19. Previous studies have indicated that there is a higher frequency of fractures among males and younger age groups. Maxillofacial fractures in children are not common and injuries tend to be less
Key words: hospitalization; jaw fractures; orofacial trauma. Accepted for publication 17 January 2006 Available online 2 March 2006
severe in young children than in older children13,20. Isolated mandibular fractures are most common, followed by isolated midface fractures12,19. Little data exist on the analysis of jaw fractures in Australia and none in Western Australia. This study was a retrospective analysis of all hospitalizations for jaw fractures in Western Australia between the years 1999–2000 and 2002– 2003.The aims were to determine the incidence, distribution between males
# 2006 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
659
Analysis of jaw fractures in Western Australia population and females, different age groups, aboriginal and non-aboriginal groups, and rural and urban populations. The economic impact of jaw fracture hospitalizations was also determined. Methods Study population
According to the last National Census in 2001, there were approximately 1.9 million people living in Western Australia. Approximately 73% of the population lived in metropolitan Perth and 6% were of aboriginal or Torres Strait Islander descent2. Statistical analysis
Hospital data were obtained from the Western Australian Morbidity Data System (HMDS). Principal diagnosis, classified by the International Classification of Disease (ICD-10 AM) system was obtained from every patient discharged from every private and public hospital in WA for the years 1999–200217. Maxillofacial fractures were identified as the cases with an ICD-10 diagnosis code in the range S02.40–S02.6. Primary place of residence at the time of hospitalization, and aboriginality were also analysed. In rate calculations, population data (i.e. denominators) were obtained from estimates calculated by the Health Department of Western Australia. They are derived from census data collected by the Australian Bureau of Statistics. Age-specific and age-standardized rates were calculated using the Rates Calculator, a software package developed by the Health Department of Western Australia. All rates were calculated per 100,000 person-years. The Accessibility/Remoteness Index of Australia (ARIA) was used to assign each Statistical Local Area (SLA) an ARIA category and an ARIA score. This Index uses distances to population centres as the basis for quantifying service access and, hence, remoteness. ARIA categories used were highly accessible (HA), accessible (A), moderately accessible (MA), remote (R) and very remote (VR). ARIA scores of 0 (unrestricted accessibility to goods and services) to 12 (very little accessibility to goods and services) were used16. The Index of Relative Socio-Economic Disadvantage (IRSD) aggregated to Statistical Local Area level was assigned to each admission. The IRSD is a composite measure derived from multiple weighted socio-economic variables collected in the 2001 Australian Bureau of Statistics Cen-
Table 1. Number of hospital admissions for jaw fractures from 1999 to 2003 N (percent of total admissions) Male Financial years 1999–2000 2000–2001 2001–2002 2002–2003
484 545 521 542
Female
(18.6) (20.9) (20.0) (20.8)
sus3. This index includes all variables that either reflect or measure disadvantage. IRSD values were ranked into quartiles ranging from high to low disadvantage. All statistical analyses were undertaken using the SPSS (version 11) package. Significant differences between rates were based on non-overlapping 95% confidence intervals (P < 0.05).
130 128 114 139
(5.0) (4.9) (4.4) (5.3)
All 614 673 635 681
(23.6) (25.8) (24.4) (26.2)
maxillary, while the distribution was more even among non-aboriginal persons. There were no gender differences regarding the site of fractures. The majority of admissions were to metropolitan teaching hospitals (Table 2).
Rates of hospitalization
By aboriginal status Results
A total of 2603 patients were admitted during 1999–2000 to 2002–2003 to hospitals in Western Australia for the principal diagnosis of fracture of the mandible, maxilla or both. The total number of persons admitted for jaw fractures increased over the 4-year study period (Table 1). Males were more likely (n = 2092; 80.4%) than females to be admitted for a jaw fracture (Table 2). About one-quarter (26.2%) of all admissions were for aboriginal persons (Table 2). Jaw fractures were the most common reason for oral health-related admissions to hospital for an aboriginal adult (42% of all oral health condition admissions) compared with 3.7% for a non-indigenous person. The average age of females admitted (33.8 years) was higher than that of males (27 years) (Table 2). Fractures of the mandible were more common (61.9%) than maxillary fractures (38.1%). Aboriginal persons were admitted with far more mandibular fractures than
Over the 4-year study period, males in each age group had higher hospitalization rates for jaw fractures than females (Fig. 1). There were statistically significant differences (P < 0.05) in the hospitalization rates between aboriginal and non-aboriginal persons overall, as well as in all age groups, except the 55+ age group (Table 3). Aboriginal persons had nearly 10 times the hospitalization rate of non-aboriginal persons (261 per 100,000 compared with 26.3 per 100,000; Table 3). Aboriginal males were 7.7 times more likely to be admitted for jaw fractures than non-aboriginal males, and aboriginal females were 22.3 times more likely to be admitted for jaw fractures than nonaboriginal females (Table 3). The highest rates amongst males were in the 25–29year age group for aboriginal, and 20–24years for non-aboriginal males (Fig. 1). The highest rates amongst females were in the 25–29-year age group for aboriginal females and the 15–19-year age group for non-aboriginal females (Fig. 1).
Table 2. Number of hospitalizations for jaw fractures from 1999 to 2003: ages of admitted persons, gender, aboriginal status and hospital types N (percent of total admissions) All male All female
Average age (SD)
2092 (80.4) 511 (19.6)
27 (12.1) 33.8 (20.25)
453 (17.4) 228 (8.8) 681 (26.2)
26.59 (9.42) 26.78 (8.87) 26.65 (9.23)
Non-Aboriginal male Non-Aboriginal female All non-Aboriginal
1639 (62.9) 283 (10.9) 1922 (73.8)
27.12 (12.74) 39.59 (24.59) 28.95 (15.71)
Metropolitan teaching hospitals Metropolitan public hospitals Metropolitan private hospitals Country hospitals
1814 20 286 483
Aboriginal male Aboriginal female All Aboriginal
(69.7) (0.8) (11.0) (18.5)
660
Kruger et al. ginal persons admitted for jaw fractures were too low in some IRSD categories, reliable rates could not be determined for aboriginal persons. Length of stay
The average length of stay in hospital was 2.31 days (SD = 2.96) ranging from 1 to 72 days. Costs of hospitalisation
Fig. 1. Jaw fractures rates by age group: 1999–2003.
for jaw fractures were too low in some ARIA categories, reliable rates could not be determined for aboriginal persons.
By residential location
Fracture rates were significantly (P < 0.05) higher in rural (61.9 per 100,000) than in urban areas (25.3 per 100,000) (Table 3).
Index of relative socio-economic disadvantage
Accessibility and Remoteness Index of Residence
Daily and seasonal variation
The rate of jaw fractures was significantly higher in the most disadvantaged IRSD category (Table 4). The rate was lowest in the least disadvantaged category (Table 4). Because the numbers of abori-
The rate of jaw fractures was significantly highest in the very remote areas (Table 4). It was lowest in remote areas. Because the numbers of aboriginal persons admitted
Table 3. Hospitalization rates for jaw fractures over 4 years: gender, age-group and location differences between aboriginal and non-aboriginal groups Aboriginal
Non-aboriginal
Ratea
CI (95%)b
Ratea
CI (95%)b
IRR
Male Female All
347.5 174.6 261.0
315.5–379.4 152.0–197.3 241.4–280.6
44.8 7.8 26.3
42.6–47.0 6.9–8.7 25.1–27.5
7.7 22.3 9.9
0–19 years 20–24 years 25–29 years 30–34 years 35–39 years 40–44 years 45–49 years 50–54 years 55+ years
123.02 583.7 696.5 608.1 366.3 324 303.9 132.6 11.62
100.94–145.11 481.52–685.14 586.48–808.01 502.86–716.65 277.98–456.48 230.36–417.53 203.45–405.25 53.49–208.42 4.33–27.58
19.4 79.7 56.5 44.3 28.6 17.2 16 11.8 13.0
18.11–22.01 71.97–87.52 50.10–62.81 38.78–49.85 24.20–32.91 13.83–20.61 12.59–19.34 8.74–14.77 8.71–11.97
6.47 7.32 12.33 13.37 12.81 18.84 18.99 11.24 0.89
Urban Rate Aboriginal Non-aboriginal All a b
a
165.6 23.0 25.3
Rural b
a
CI (95%)
Rate
139.3–191.9 21.8–24.2 24.0–26.4
311.6 35.5 61.9
Rates are age-standardized and per 100,000 of the population. The 95% confidence interval for the age-standardized rate.
Each patient admitted to hospital has a principal diagnosis (main reason for admission) and on this basis they are categorized in a diagnosis related group. The diagnosis related group is a character patient classification scheme that provides a means of relating the number and types of patients treated in a hospital to the resources required by the hospital. The cost estimate of jaw fractures ranged from US$ 990 to US$ 45,019 per patient. The average estimated cost per patient was US$ 4,184 (SD = $5863). Over the 4-year study period the total costs for all jaw fracture hospitalizations exceeded US$ 7.6 million. Jaw fracture costs contributed 7.1% to the total costs of all oral healthrelated hospitalizations.
CI (95%)b
IRR
285.0–338.2 32.6–38.4 58.2–65.6
1.8 1.5 2.4
The highest rates of admissions for jaw fractures were on Fridays, Saturdays and Sundays (Fig. 2). There was little variation between seasonal hospital admissions for jaw fractures—most (28%) were in autumn (March–May), 25% were in summer (December–February), 24% in winter (June–August) and 21% in spring (September–November). Discussion
In Western Australia higher rates of hospitalization for jaw fractures were found among males, aboriginal persons, rural dwellers, those living in very remote areas and people who are socio-economically most disadvantaged. In this study, 80% of all admissions for jaw fractures were for males. This compares well with previous studies where the percentage of males compared to females reporting with jaw fractures were between 78 and 92%1,5,7,13,14. As in previous research, this study also indicated that mandibular fractures were more prevalent than maxillary fractures5,7,8,12,19. Jaw fracture hospitalization rates for aboriginal people were significantly higher than those for non-aboriginal per-
Analysis of jaw fractures in Western Australia population Table 4. Hospitalization rates for jaw fractures in each of the Accessibility and Remoteness Index , and Index of Relative Socio-Economic Disadvantage Categories ARIA Highly accessible Accessible Moderately accessible Remote Very remote IRSD Most disadvantaged Above average disadvantage Average disadvantage Below average disadvantage Least disadvantage a b
Ratea
CI (95%)b
28.16 33.56 41.64 15.80 101.27
26.75–29.57 29.07–38.04 35.67–47.60 11.13–20.47 93.00–109.54
91.49 34.10 30.75 25.53 23.01
82.95–100.04 32.17–36.03 27.83–33.67 22.76–28.30 19.59–26.44
Rates are crude population rates per 100,000. The 95% confidence interval for the crude population rate.
sons, in all age groups except the 55+ age group. These are consistent with general injury mortality and morbidity data for aboriginal and Torres Strait Islander people, which indicate that general injury rates for aboriginal Australians are much higher than for non-aboriginal Australians6,10. The difference in the older age groups can be attributed to the younger age distribution and lower life expectancy for aboriginal Australians. For aboriginal males and females rates peaked in the age group 25–29-years, for non-aboriginal males in the 20–24-year age groups and for non-aboriginal females in the 15–19-year age group. The higher rates among young people which were also found in surveys on traumatic injuries in Australia were fractures of the head area, in those aged 15 to 29 years old. Fractures in children were uncommon and this is consistent with observations in similar studies11,13,20. In this study there were higher rates in the rural areas overall, and while using the ARIA index, rates were highest among people in the very remote areas. To be able to comment on why rates are higher in these
areas, the aetiology of fractures need to be determined, and that was not possible in this study. Previous research has analysed these aspects and found that facial fractures are most commonly caused by assault or interpersonal violence, motor vehicle accidents, sports injuries and falls4,5,19,22,23. It is also known that general injury and hospitalization for injury rates are higher among aboriginal people6,9, and the most common causes of injury for which aboriginal people were hospitalized were transport related, interpersonal violence and accidental falls6,9. Aboriginal people are more likely to live in rural and remote areas in Western Australia. Patients stayed in hospital for an average of 2.31 days, and rural patients stayed slightly longer than urban patients. It might be because rural patients in some cases have to travel to metropolitan hospitals and are being discharged later (because of follow-up care access issues when returning to the country). The economic impact of fracture hospitalizations is demonstrated by the cost of more than US$ 7.6 million over a 4-year period.
Fig. 2. Daily variations of jaw fracture rate admissions: difference between rural and urban areas.
661
In this study most fracture admissions were in autumn and summer. Previous studies indicated higher rates of jaw fractures in summer7,8 and an Australian study19 also indicated high rates in late autumn/early winter months. Most fracture admissions were on Fridays, Saturdays and Sundays. Previous findings in 2 aboriginal communities indicated that general injuries were most prevalent on Thursdays, Fridays and Saturdays9. The difference in admission days between city and rural patients (Fig. 2) might be indicative of immediate admissions for city dwellers, but delayed admissions for rural dwellers who have to travel to metropolitan hospitals. This study clearly indicates the burden of jaw fractures on the Western Australian population, in terms of physical and economic impact. As aetiological data indicate that some of these injuries can be prevented, future efforts should be aimed at preventative programmes, especially in the high-risk groups. References 1. Al Ahmed HE, Jaber MA, Abu Fanas SH, Karas M. The pattern of maxillofacial fractures in Sharjah, United Arab Emirates: a review of 230 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004: 98: 166–170. 2. AUSTRALIAN BUREAU OF STATISTICS. 2001 Census Basic Community Profiles and Snapshots: 2002. Canberra (ACT): ABS 2002. 3. AUSTRALIAN BUREAU OF STATISTICS. Census of Population and Housing: Socio-Economic Indexes for Area. Canberra (ACT): ABS 2002 (ABS catalogue no. 2039). 4. BRADLEY C, HARRISON J. Descriptive Epidemiology of Traumatic Fractures in Australia. Injury Research and Statistics Series Number 17. Adelaide: AIHW 2004 (AIHW catalogue no. INJCAT 57). 5. Dongas P, Hall GM. Mandibular fracture patterns in Tasmania, Australia. Aust Dent J 2002: 47: 131–137. 6. Edwards TJ, David DJ, Simpson DA, Abbott AA. Patterns of mandibular fractures in Adelaide, South Australia. Aust N Z J Surg 1994: 64: 307–311. 7. Erol B, Tanrikulu R, Gorgun B. Maxillofacial fractures. Analysis of demographic distribution and treatment in 2901 patients (25-year experience). J Craniomaxillofac Surg 2004: 32: 308–313. 8. Gassner R, Tuli T, Hacl O, Rudisch A, Ulmer H. Cranio-maxillofacial trauma: a 10 year review of 9543 cases with 21067 injuries. J Craniomaxillofac Surg 2003: 31: 51–61. 9. GLADMAN D, HUNTER E, MCDERMOTT R, MERRITT T, TULIP F. Study of injury in five Cape York communities. AIHW National Injury Surveillance Unit and Queensland Health 1997 (catalogue no. INJ12).
662
Kruger et al.
10. HELPS YLM, HARRISON JE. Reported Injury Mortality of Aboriginal and Torres Strait Islander people in Australia, 19972000. Injury technical paper series no. 4. Adelaide: AIHW 2004 (AIHW catalogue no. INJCAT 66). 11. Holland AJ, Broome C, Steinberg A, Cass DT. Facial fractures in children. Pediatr Emerg Care 2001: 17: 157–160. 12. Iida S, Kogo M, Sugiura T, Mima T, Matsuya T. Retrospective analysis of 1502 patients with facial fractures. Int J Oral Maxillofac Surg 2001: 30: 286–290. 13. Iida S, Matsuya T. Paediatric maxillofacial fractures: their aetiological characters and fracture patterns. J Craniomaxillofac Surg 2002: 30: 237–241. 14. Kieser J, Stephenson S, Liston PN, Tong DC, Langley JD. Serious facial fractures in New Zealand from 1979 to 1998. Int J Oral Maxillofac Surg 2002: 31: 206–209. 15. Leathers R, Le AD, Black E, McQuirter JL. Orofacial injury in underserved minority populations. Dent Clin North Am 2003: 47: 127–139.
16. Measuring Remoteness: Accessibility/ Remoteness Index of Australia (ARIA). Canberra (ACT): Department of Health and Aged Care; 2001. Occasional Papers: New Series No.: 14. 17. NCCH. The International Classification of Diseases and Related Health Problems, 11th Revision, Australian Modification (ICD-10-AM). Vol I–V: Lidcombe, Australia: National Centre for Classification in Health 2000. 18. Oikarinen K, Schitz P, Thalib L, Sandor GKB, Clokie C, Meisami T, Safar S, Moilanen M, Belal M. Differences in the etiology of mandibular fractures in Kuwait, Canada, and Finland. Dent Traumatol 2004: 20: 241–245. 19. Schon R, Roveda SIL, Carter B. Mandibular fractures in Townsville, Australia: incidence, aetiology and treatment using the 2.0AO/ASIF miniplate system. Br J Oral Maxillofac Surg 2001: 39: 145– 148. 20. Shaikh Z, Worrall S. Epidemiology of facial trauma in a sample of patients aged 1–18 years. Injury 2002: 33: 669–671.
21. Shand JM, Heggie AA. Maxillofacial injuries at the Royal Children’s Hospital of Melbourne: a five year review. Ann R Australas Coll Dent Surg 2000: 15: 166– 169. 22. Thaller SR, Beal SL. Maxillofacial trauma: a potentially fatal injury. Ann Plast Surg 1991: 27: 281–283. 23. Watt K, Purdie DM, Roche AM, McClure RJ. Risk of injury from acute alcohol consumption and the influence of confounders. Addiction 2004: 99: 1262– 1273. Address: Estie Kruger The Centre for Rural and Remote Oral Health The University of Western Australia 35 Stirling Highway Crawley WA 6009 Australia Tel: +61 8 9346 7248 Fax: +61 8 9346 7237 E-mail: [email protected]
Evidence-Based Therapy Trauma
Jaw fractures in the indigenous and non-indigenous populations of Western Australia: 1999–2003
E. Kruger, K. Smith, M. Tennant The Centre for Rural and Remote Oral Health, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
E. Kruger, K. Smith, M. Tennant: Jaw fractures in the indigenous and nonindigenous populations of Western Australia: 1999–2003. Int. J. Oral Maxillofac. Surg. 2006; 35: 658–662. # 2006 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. Little data exist on the analysis of jaw fractures in Australia, and none in Western Australia. This study was a retrospective analysis of all hospitalizations for jaw fractures in Western Australia between the years 1999–2000 and 2002–2003. The aims were to determine the incidence, distribution between males and females, different age groups, aboriginal and non-aboriginal groups, and rural and urban populations. The economic impact of jaw fracture hospitalizations was also determined. Males were more likely (80.4%) than females to be admitted for a jaw fracture. Fractures of the mandible were more common (61.9%) than maxillary fractures (38.1%). Aboriginal persons had nearly 10 times more hospitalization rate than that of non-aboriginal persons. Fracture rates were significantly (P < 0.05) higher in rural (61.9 per 100,000) than in urban areas. Over the 4-year study period the total costs for all jaw fracture hospitalizations exceeded US$ 7.6 million. This study clearly indicates the burden of jaw fractures on the Western Australian population, in terms of physical and economic impact.
Injuries to the soft tissue and bony skeleton of the face constitute a high percentage of all traumatic admissions to Emergency Departments22. The incidence and aetiology of maxillofacial fractures vary widely between different countries as a result of various contributing factors, such as age, gender, the environment and the socioeconomic status and culture of the patient. The causes and risk factors for fractures differ between countries, with motor vehicle accidents and assault being the most 0901-5027/070658 + 05 $30.00/0
common. Previous research also indicates a relationship between alcohol and substance abuse and facial injuries15,18. In some countries sporting injuries are also a common cause of jaw fractures5,19,21. Seasonal analysis indicates that most maxillofacial trauma occurs in summer7,8,19. Previous studies have indicated that there is a higher frequency of fractures among males and younger age groups. Maxillofacial fractures in children are not common and injuries tend to be less
Key words: hospitalization; jaw fractures; orofacial trauma. Accepted for publication 17 January 2006 Available online 2 March 2006
severe in young children than in older children13,20. Isolated mandibular fractures are most common, followed by isolated midface fractures12,19. Little data exist on the analysis of jaw fractures in Australia and none in Western Australia. This study was a retrospective analysis of all hospitalizations for jaw fractures in Western Australia between the years 1999–2000 and 2002– 2003.The aims were to determine the incidence, distribution between males
# 2006 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
659
Analysis of jaw fractures in Western Australia population and females, different age groups, aboriginal and non-aboriginal groups, and rural and urban populations. The economic impact of jaw fracture hospitalizations was also determined. Methods Study population
According to the last National Census in 2001, there were approximately 1.9 million people living in Western Australia. Approximately 73% of the population lived in metropolitan Perth and 6% were of aboriginal or Torres Strait Islander descent2. Statistical analysis
Hospital data were obtained from the Western Australian Morbidity Data System (HMDS). Principal diagnosis, classified by the International Classification of Disease (ICD-10 AM) system was obtained from every patient discharged from every private and public hospital in WA for the years 1999–200217. Maxillofacial fractures were identified as the cases with an ICD-10 diagnosis code in the range S02.40–S02.6. Primary place of residence at the time of hospitalization, and aboriginality were also analysed. In rate calculations, population data (i.e. denominators) were obtained from estimates calculated by the Health Department of Western Australia. They are derived from census data collected by the Australian Bureau of Statistics. Age-specific and age-standardized rates were calculated using the Rates Calculator, a software package developed by the Health Department of Western Australia. All rates were calculated per 100,000 person-years. The Accessibility/Remoteness Index of Australia (ARIA) was used to assign each Statistical Local Area (SLA) an ARIA category and an ARIA score. This Index uses distances to population centres as the basis for quantifying service access and, hence, remoteness. ARIA categories used were highly accessible (HA), accessible (A), moderately accessible (MA), remote (R) and very remote (VR). ARIA scores of 0 (unrestricted accessibility to goods and services) to 12 (very little accessibility to goods and services) were used16. The Index of Relative Socio-Economic Disadvantage (IRSD) aggregated to Statistical Local Area level was assigned to each admission. The IRSD is a composite measure derived from multiple weighted socio-economic variables collected in the 2001 Australian Bureau of Statistics Cen-
Table 1. Number of hospital admissions for jaw fractures from 1999 to 2003 N (percent of total admissions) Male Financial years 1999–2000 2000–2001 2001–2002 2002–2003
484 545 521 542
Female
(18.6) (20.9) (20.0) (20.8)
sus3. This index includes all variables that either reflect or measure disadvantage. IRSD values were ranked into quartiles ranging from high to low disadvantage. All statistical analyses were undertaken using the SPSS (version 11) package. Significant differences between rates were based on non-overlapping 95% confidence intervals (P < 0.05).
130 128 114 139
(5.0) (4.9) (4.4) (5.3)
All 614 673 635 681
(23.6) (25.8) (24.4) (26.2)
maxillary, while the distribution was more even among non-aboriginal persons. There were no gender differences regarding the site of fractures. The majority of admissions were to metropolitan teaching hospitals (Table 2).
Rates of hospitalization
By aboriginal status Results
A total of 2603 patients were admitted during 1999–2000 to 2002–2003 to hospitals in Western Australia for the principal diagnosis of fracture of the mandible, maxilla or both. The total number of persons admitted for jaw fractures increased over the 4-year study period (Table 1). Males were more likely (n = 2092; 80.4%) than females to be admitted for a jaw fracture (Table 2). About one-quarter (26.2%) of all admissions were for aboriginal persons (Table 2). Jaw fractures were the most common reason for oral health-related admissions to hospital for an aboriginal adult (42% of all oral health condition admissions) compared with 3.7% for a non-indigenous person. The average age of females admitted (33.8 years) was higher than that of males (27 years) (Table 2). Fractures of the mandible were more common (61.9%) than maxillary fractures (38.1%). Aboriginal persons were admitted with far more mandibular fractures than
Over the 4-year study period, males in each age group had higher hospitalization rates for jaw fractures than females (Fig. 1). There were statistically significant differences (P < 0.05) in the hospitalization rates between aboriginal and non-aboriginal persons overall, as well as in all age groups, except the 55+ age group (Table 3). Aboriginal persons had nearly 10 times the hospitalization rate of non-aboriginal persons (261 per 100,000 compared with 26.3 per 100,000; Table 3). Aboriginal males were 7.7 times more likely to be admitted for jaw fractures than non-aboriginal males, and aboriginal females were 22.3 times more likely to be admitted for jaw fractures than nonaboriginal females (Table 3). The highest rates amongst males were in the 25–29year age group for aboriginal, and 20–24years for non-aboriginal males (Fig. 1). The highest rates amongst females were in the 25–29-year age group for aboriginal females and the 15–19-year age group for non-aboriginal females (Fig. 1).
Table 2. Number of hospitalizations for jaw fractures from 1999 to 2003: ages of admitted persons, gender, aboriginal status and hospital types N (percent of total admissions) All male All female
Average age (SD)
2092 (80.4) 511 (19.6)
27 (12.1) 33.8 (20.25)
453 (17.4) 228 (8.8) 681 (26.2)
26.59 (9.42) 26.78 (8.87) 26.65 (9.23)
Non-Aboriginal male Non-Aboriginal female All non-Aboriginal
1639 (62.9) 283 (10.9) 1922 (73.8)
27.12 (12.74) 39.59 (24.59) 28.95 (15.71)
Metropolitan teaching hospitals Metropolitan public hospitals Metropolitan private hospitals Country hospitals
1814 20 286 483
Aboriginal male Aboriginal female All Aboriginal
(69.7) (0.8) (11.0) (18.5)
660
Kruger et al. ginal persons admitted for jaw fractures were too low in some IRSD categories, reliable rates could not be determined for aboriginal persons. Length of stay
The average length of stay in hospital was 2.31 days (SD = 2.96) ranging from 1 to 72 days. Costs of hospitalisation
Fig. 1. Jaw fractures rates by age group: 1999–2003.
for jaw fractures were too low in some ARIA categories, reliable rates could not be determined for aboriginal persons.
By residential location
Fracture rates were significantly (P < 0.05) higher in rural (61.9 per 100,000) than in urban areas (25.3 per 100,000) (Table 3).
Index of relative socio-economic disadvantage
Accessibility and Remoteness Index of Residence
Daily and seasonal variation
The rate of jaw fractures was significantly higher in the most disadvantaged IRSD category (Table 4). The rate was lowest in the least disadvantaged category (Table 4). Because the numbers of abori-
The rate of jaw fractures was significantly highest in the very remote areas (Table 4). It was lowest in remote areas. Because the numbers of aboriginal persons admitted
Table 3. Hospitalization rates for jaw fractures over 4 years: gender, age-group and location differences between aboriginal and non-aboriginal groups Aboriginal
Non-aboriginal
Ratea
CI (95%)b
Ratea
CI (95%)b
IRR
Male Female All
347.5 174.6 261.0
315.5–379.4 152.0–197.3 241.4–280.6
44.8 7.8 26.3
42.6–47.0 6.9–8.7 25.1–27.5
7.7 22.3 9.9
0–19 years 20–24 years 25–29 years 30–34 years 35–39 years 40–44 years 45–49 years 50–54 years 55+ years
123.02 583.7 696.5 608.1 366.3 324 303.9 132.6 11.62
100.94–145.11 481.52–685.14 586.48–808.01 502.86–716.65 277.98–456.48 230.36–417.53 203.45–405.25 53.49–208.42 4.33–27.58
19.4 79.7 56.5 44.3 28.6 17.2 16 11.8 13.0
18.11–22.01 71.97–87.52 50.10–62.81 38.78–49.85 24.20–32.91 13.83–20.61 12.59–19.34 8.74–14.77 8.71–11.97
6.47 7.32 12.33 13.37 12.81 18.84 18.99 11.24 0.89
Urban Rate Aboriginal Non-aboriginal All a b
a
165.6 23.0 25.3
Rural b
a
CI (95%)
Rate
139.3–191.9 21.8–24.2 24.0–26.4
311.6 35.5 61.9
Rates are age-standardized and per 100,000 of the population. The 95% confidence interval for the age-standardized rate.
Each patient admitted to hospital has a principal diagnosis (main reason for admission) and on this basis they are categorized in a diagnosis related group. The diagnosis related group is a character patient classification scheme that provides a means of relating the number and types of patients treated in a hospital to the resources required by the hospital. The cost estimate of jaw fractures ranged from US$ 990 to US$ 45,019 per patient. The average estimated cost per patient was US$ 4,184 (SD = $5863). Over the 4-year study period the total costs for all jaw fracture hospitalizations exceeded US$ 7.6 million. Jaw fracture costs contributed 7.1% to the total costs of all oral healthrelated hospitalizations.
CI (95%)b
IRR
285.0–338.2 32.6–38.4 58.2–65.6
1.8 1.5 2.4
The highest rates of admissions for jaw fractures were on Fridays, Saturdays and Sundays (Fig. 2). There was little variation between seasonal hospital admissions for jaw fractures—most (28%) were in autumn (March–May), 25% were in summer (December–February), 24% in winter (June–August) and 21% in spring (September–November). Discussion
In Western Australia higher rates of hospitalization for jaw fractures were found among males, aboriginal persons, rural dwellers, those living in very remote areas and people who are socio-economically most disadvantaged. In this study, 80% of all admissions for jaw fractures were for males. This compares well with previous studies where the percentage of males compared to females reporting with jaw fractures were between 78 and 92%1,5,7,13,14. As in previous research, this study also indicated that mandibular fractures were more prevalent than maxillary fractures5,7,8,12,19. Jaw fracture hospitalization rates for aboriginal people were significantly higher than those for non-aboriginal per-
Analysis of jaw fractures in Western Australia population Table 4. Hospitalization rates for jaw fractures in each of the Accessibility and Remoteness Index , and Index of Relative Socio-Economic Disadvantage Categories ARIA Highly accessible Accessible Moderately accessible Remote Very remote IRSD Most disadvantaged Above average disadvantage Average disadvantage Below average disadvantage Least disadvantage a b
Ratea
CI (95%)b
28.16 33.56 41.64 15.80 101.27
26.75–29.57 29.07–38.04 35.67–47.60 11.13–20.47 93.00–109.54
91.49 34.10 30.75 25.53 23.01
82.95–100.04 32.17–36.03 27.83–33.67 22.76–28.30 19.59–26.44
Rates are crude population rates per 100,000. The 95% confidence interval for the crude population rate.
sons, in all age groups except the 55+ age group. These are consistent with general injury mortality and morbidity data for aboriginal and Torres Strait Islander people, which indicate that general injury rates for aboriginal Australians are much higher than for non-aboriginal Australians6,10. The difference in the older age groups can be attributed to the younger age distribution and lower life expectancy for aboriginal Australians. For aboriginal males and females rates peaked in the age group 25–29-years, for non-aboriginal males in the 20–24-year age groups and for non-aboriginal females in the 15–19-year age group. The higher rates among young people which were also found in surveys on traumatic injuries in Australia were fractures of the head area, in those aged 15 to 29 years old. Fractures in children were uncommon and this is consistent with observations in similar studies11,13,20. In this study there were higher rates in the rural areas overall, and while using the ARIA index, rates were highest among people in the very remote areas. To be able to comment on why rates are higher in these
areas, the aetiology of fractures need to be determined, and that was not possible in this study. Previous research has analysed these aspects and found that facial fractures are most commonly caused by assault or interpersonal violence, motor vehicle accidents, sports injuries and falls4,5,19,22,23. It is also known that general injury and hospitalization for injury rates are higher among aboriginal people6,9, and the most common causes of injury for which aboriginal people were hospitalized were transport related, interpersonal violence and accidental falls6,9. Aboriginal people are more likely to live in rural and remote areas in Western Australia. Patients stayed in hospital for an average of 2.31 days, and rural patients stayed slightly longer than urban patients. It might be because rural patients in some cases have to travel to metropolitan hospitals and are being discharged later (because of follow-up care access issues when returning to the country). The economic impact of fracture hospitalizations is demonstrated by the cost of more than US$ 7.6 million over a 4-year period.
Fig. 2. Daily variations of jaw fracture rate admissions: difference between rural and urban areas.
661
In this study most fracture admissions were in autumn and summer. Previous studies indicated higher rates of jaw fractures in summer7,8 and an Australian study19 also indicated high rates in late autumn/early winter months. Most fracture admissions were on Fridays, Saturdays and Sundays. Previous findings in 2 aboriginal communities indicated that general injuries were most prevalent on Thursdays, Fridays and Saturdays9. The difference in admission days between city and rural patients (Fig. 2) might be indicative of immediate admissions for city dwellers, but delayed admissions for rural dwellers who have to travel to metropolitan hospitals. This study clearly indicates the burden of jaw fractures on the Western Australian population, in terms of physical and economic impact. As aetiological data indicate that some of these injuries can be prevented, future efforts should be aimed at preventative programmes, especially in the high-risk groups. References 1. Al Ahmed HE, Jaber MA, Abu Fanas SH, Karas M. The pattern of maxillofacial fractures in Sharjah, United Arab Emirates: a review of 230 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004: 98: 166–170. 2. AUSTRALIAN BUREAU OF STATISTICS. 2001 Census Basic Community Profiles and Snapshots: 2002. Canberra (ACT): ABS 2002. 3. AUSTRALIAN BUREAU OF STATISTICS. Census of Population and Housing: Socio-Economic Indexes for Area. Canberra (ACT): ABS 2002 (ABS catalogue no. 2039). 4. BRADLEY C, HARRISON J. Descriptive Epidemiology of Traumatic Fractures in Australia. Injury Research and Statistics Series Number 17. Adelaide: AIHW 2004 (AIHW catalogue no. INJCAT 57). 5. Dongas P, Hall GM. Mandibular fracture patterns in Tasmania, Australia. Aust Dent J 2002: 47: 131–137. 6. Edwards TJ, David DJ, Simpson DA, Abbott AA. Patterns of mandibular fractures in Adelaide, South Australia. Aust N Z J Surg 1994: 64: 307–311. 7. Erol B, Tanrikulu R, Gorgun B. Maxillofacial fractures. Analysis of demographic distribution and treatment in 2901 patients (25-year experience). J Craniomaxillofac Surg 2004: 32: 308–313. 8. Gassner R, Tuli T, Hacl O, Rudisch A, Ulmer H. Cranio-maxillofacial trauma: a 10 year review of 9543 cases with 21067 injuries. J Craniomaxillofac Surg 2003: 31: 51–61. 9. GLADMAN D, HUNTER E, MCDERMOTT R, MERRITT T, TULIP F. Study of injury in five Cape York communities. AIHW National Injury Surveillance Unit and Queensland Health 1997 (catalogue no. INJ12).
662
Kruger et al.
10. HELPS YLM, HARRISON JE. Reported Injury Mortality of Aboriginal and Torres Strait Islander people in Australia, 19972000. Injury technical paper series no. 4. Adelaide: AIHW 2004 (AIHW catalogue no. INJCAT 66). 11. Holland AJ, Broome C, Steinberg A, Cass DT. Facial fractures in children. Pediatr Emerg Care 2001: 17: 157–160. 12. Iida S, Kogo M, Sugiura T, Mima T, Matsuya T. Retrospective analysis of 1502 patients with facial fractures. Int J Oral Maxillofac Surg 2001: 30: 286–290. 13. Iida S, Matsuya T. Paediatric maxillofacial fractures: their aetiological characters and fracture patterns. J Craniomaxillofac Surg 2002: 30: 237–241. 14. Kieser J, Stephenson S, Liston PN, Tong DC, Langley JD. Serious facial fractures in New Zealand from 1979 to 1998. Int J Oral Maxillofac Surg 2002: 31: 206–209. 15. Leathers R, Le AD, Black E, McQuirter JL. Orofacial injury in underserved minority populations. Dent Clin North Am 2003: 47: 127–139.
16. Measuring Remoteness: Accessibility/ Remoteness Index of Australia (ARIA). Canberra (ACT): Department of Health and Aged Care; 2001. Occasional Papers: New Series No.: 14. 17. NCCH. The International Classification of Diseases and Related Health Problems, 11th Revision, Australian Modification (ICD-10-AM). Vol I–V: Lidcombe, Australia: National Centre for Classification in Health 2000. 18. Oikarinen K, Schitz P, Thalib L, Sandor GKB, Clokie C, Meisami T, Safar S, Moilanen M, Belal M. Differences in the etiology of mandibular fractures in Kuwait, Canada, and Finland. Dent Traumatol 2004: 20: 241–245. 19. Schon R, Roveda SIL, Carter B. Mandibular fractures in Townsville, Australia: incidence, aetiology and treatment using the 2.0AO/ASIF miniplate system. Br J Oral Maxillofac Surg 2001: 39: 145– 148. 20. Shaikh Z, Worrall S. Epidemiology of facial trauma in a sample of patients aged 1–18 years. Injury 2002: 33: 669–671.
21. Shand JM, Heggie AA. Maxillofacial injuries at the Royal Children’s Hospital of Melbourne: a five year review. Ann R Australas Coll Dent Surg 2000: 15: 166– 169. 22. Thaller SR, Beal SL. Maxillofacial trauma: a potentially fatal injury. Ann Plast Surg 1991: 27: 281–283. 23. Watt K, Purdie DM, Roche AM, McClure RJ. Risk of injury from acute alcohol consumption and the influence of confounders. Addiction 2004: 99: 1262– 1273. Address: Estie Kruger The Centre for Rural and Remote Oral Health The University of Western Australia 35 Stirling Highway Crawley WA 6009 Australia Tel: +61 8 9346 7248 Fax: +61 8 9346 7237 E-mail: [email protected]