ORIGINAL CONTRIBUTION
motorcycle helmets
M o t o r c y c l e Crash Injuries and Costs: Effect of a Reenacted Comprehensive Helmet Use Law From the Department of Emergency
Robert L Muelleman, MD, FACEP*
Study objectives: To document the effect of a reenacted comprehen-
Medical Services, University of
Edward J Mlinek, MD, FACEP*
sive helmet use law on injuries and fatalities.
Nebraska Medical Center;* and
Paul E Collicott, MD, FACSt
Design: Retrospective before-and-after analysis.
Department of Surgery, University of Nebraska College of Medicine, Omaha. "~ Receivedfor publication August 30, 1991. Revision received October 18,
Setting: Two urban counties representing 40% of Nebraska's population.
Participants: Six hundred seventy-one patients reported as injured to the Nebraska Department of Roads in the period from one year before through one year after the reenactment on January 1, 1989.
1991. Acceptedfor publication
Results: The helmet use law was temporally associated with a 26%
November 8, 1991.
decrease in the reported rate of motorcycle crashes in Nebraska compared with five other midwestern states. There were sharp declines in the number (and rates) of reported injured, hospital transports, hospital admissions, severe nonhead injuries, severe head injuries, and deaths. Serious head injuries (Abbreviated Injury Score, 3 or higher) decreased 22%. The percentage of injured motorcyclists with serious head injuries was significantly lower among the helmeted motorcyclists (5%) than among the unhelmeted cyclists (14%)for the two years combined.
Presented at the Societyfor Academic Emergency Medicine Annual Meeting in Washington, DC, May 1991. This work was supported by the Insurance Institutefor Highway
Conclusion: The reenactment of a helmet use law resulted in fewer crashes, fatalities, and severe head injuries. [Muelleman RL, Mlinek EJ, Collicott PE: Motorcycle crash injuries and costs: Effect of a reenacted comprehensive helmet use law. Ann Emerg Med March 1992;21:266-272.]
Safety.
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INTRODUCTION Motorcycle crashes resulted in more than 40,000 deaths and many more injuries in the United States during the 1980s. i-s The direct and indirect costs of motorcycle trauma are high. 6 Because many motorcyclists are uninsured, much of the cost for their medical care goes unpaid or is paid by government funds. 7-13 The effectiveness of motorcycle helmets, first noted in 1941,14 has been confirmed repeatedly,a J3, ls-26 as has the ability of comprehensive helmet use laws to increase helmet use. 27-31 In states without helmet use laws or with only partial helmet use laws, the death rate from head injuries is twice as high as in states with comprehensive laws. 32 During the 1970s, 26 states repealed or weakened their comprehensive laws, resulting in increased mortality22,23, 33,34 and cost22,23,35,36 from motorcycle crashes. Only four of those states reenacted a comprehensive law during the 1980s: Louisiana, Oregon, Texas, and Nebraska. Currently, 25 states (including the District of Columbia) have comprehensive helmet use laws, 23 have partial laws, and three have no laws requiring helmet use. 37 Opponents of helmet use laws have argued that they limit personal freedom. 38 Opponents have also claimed that the laws result in higher crash rates 39 and certain types of head 4°-¢2 and neck19,al,a3 injuries, as well as an increased cost to society resulting from the permanent disability of individuals who would have been killed if they had not worn helmets .44 Others lament the fact that fewer donor organs will be available if more motorcyclists wear helmets, as To counterbalance such arguments, recent proposed federal legislation (S 1007/HR 3925) threatens to reduce apportionment of federal aid highway funds to states that fail to require the use of motorcycle helmets as well as front seat safety belts for automobile occupants. As an added incentive, the legislation also offers motorcycle helmet and safety belt grants to certain states. The purpose of this study was to document the effects of a helmet use law on crash, fatality, and severe head injury rates and acute medical charges in Nebraska. An earlier law in Nebraska was repealed in 1977, and the new law went into effect on January 1, 1989. This study allows not only timely evaluation of the reenacted law for Nebraska but also provides new information for the continuing political debate over comprehensive helmet use laws in other states.
MATERIALS AND METHODS The study used a retrospective, before-and-after design. For one year before and one year after the effective date of the new law, the study gathered data about fatalities, specific injuries, and
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costs from motorcycle crashes in two urban Nebraska counties (a clinical injury study). In addition, statewide motorcycle crash rates were examined for Nebraska and several comparison states for five years before and one year after the law's effective date (a crash rate study). C r a s h R a t e S t u d y The number of motorcycle registrations and crashes in 1984 through 1989 for Nebraska and five comparison states was obtained from the Motorcycle Statistical Annual.46 Iowa, Kansas, Oklahoma, South Dakota, and North Dakota were chosen as comparison states because they are in the same region and did not change their helmet use laws during the time period of 1984 through 1989; none has a comprehensive helmet use law. Clinical Injury Study Data were obtained from four sources: crash and registration data for the two counties from the Nebraska Department of Motor Vehicles and Department of Roads, prehospital data from ambulance and medical helicopter services, hospital data from participating hospitals, and autopsy data from county coroners. The two study counties were Douglas and Lancaster. In 1988, the two counties had a combined population of 630,000, representing 40% of the state's population. Douglas County has eight acute care hospitals with emergency departments, and Lancaster County has three. All 11 hospitals agreed to participate in the study after assurance that the medical information would be provided anonymously. Douglas County has two self-designated Level I trauma centers, two major ambulance services that are advanced life support fire department-based systems, and two medical helicopter services. Lancaster County has one Level II (American College of Surgeons verification) trauma center, one major ambulance service that is an advanced lifed support private system, and no helicopter services. Patients were included in the two-county, clinical injury study if the crash was reported to the Department of Roads, the injury was sustained in a motorcycle crash in one of the study counties, and they were transported by a participating ambulance or helicopter service to a participating hospital. Crashes reported to the Department of Roads were those that had been reported to the police after occurring on a public road and involved an injury, fatality, or at least $500 in property damage. Hospital records in the two counties were incomplete with regard to the cause of injuries (ie, motorcycle crash or other injury mechanism). Therefore, case finding began with lists of all motorcyclists reported to the Department of Roads as injured in the study counties. These lists also contained information on II~
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hehnet use, age, and gender; driver's motorcycle licensure; date, time, and location of the crash; and road surface and light conditions. The lists of injured motorcyclists from the Department of Roads were matched with prehospital information from the ambulance services. The private ambulance service in Lancaster County and both helicopter services computerized all transport information locally and were able to determine which of the reportedly injured motorcyclists they had transported in both years. Copies of their transport sheets were provided for documentation. The public ambulance services in Douglas County sent their transport sheets to the state department of health, where the information was computerized without patients' names or, in 1989, information about the cause of injury. The 1988 motorcycle-related transport sheets were located manually and then matched to the list of injured motorcyclists by date and location to identify the 1988 study patients in Douglas County. In 1989, the Douglas County ambulance services began coding transports by cause of injury (E codes), and the Department of Health provided a computer-generated list of all motorcycle-related transports at the end of that year. In addition, copies of the 1989 transport sheets were made for the study before the originals were sent to the department. The combination of copied transport sheets and any other motorcycle-related transports of patients on the Department of Health list (matched to the Department of Roads' list by date and location) identified the 1989 study patients in Douglas County. Information from the transport sheets was used to identify receiving hospitals. The ambulance services also provided additional information about helmet use and whether the injured motorcyclist was the driver or passengeL Once it was determined to which hospitals the patients had been transported, a list of patients with assigned code numbers was periodically sent to each hospital. For privacy reasons, the hospital provided information identified by the patient's code number. The hospital data included disposition, length of hospitalization, discharge disposition, evidence of readmission, organ donor status, specific injuries, insurance status, acute medical charges, and amount collected. The hospitals also provided information about helmet use. If there was a discrepancy in the helmet use reported by the Department of Roads, the ambulance service, and the receiving hospital, helmet use was coded as unknown. Injuries located from the hospital data and the coroner's reports were described and coded by one trauma nurse coordinator familiar with the Abbreviated Injury Scale (AIS) (1985 version). 47
Costs in this study included only acute medical charges. Prehospital charges, physician fees, readmission costs, and rehabilitation costs were not obtained. Charges in 1988 were converted to 1989 dollars by muhiplying by 1.085 to reflect the 8.5% inflation of medical charges from 1988 to 1989. ¢8 Because police reporting of crashes is incomplete, it is likely that some injured motorcyclists treated at the study hospitals were missed by the study design in both years. However, a sixmonth prospective ED surveillance during the second year of the study indicated that the design captured 100% of the deaths, 100% of the seriously head injured patients (AIS, 3 or higher), 92% of the seriously nonhead injmed patients (AIS, 3 or higher), and 83% of the admissions during the surveillance period. Fiftyfive percent of the less-than-seriously injured patients (AIS, less than 3) were missed by the study design. Comparison of crash rates was made by multiple regression analysis. Comparison of proportions was measured by Z2 goodness-of-fit tests. P < .05 was considered statistically significant.
RESULTS S t a t e C r a s h R a t e s Counts of motorcycle crashes and registrations during 1984 through 1989 in Nebraska and the five comparison states are given (Table 1). Both crashes and registrations declined in all states during these years, but there was a sharp decrease in crashes per 10,000 registrations in Nebraska coincident with the reinstatement of mandatory helmet use in 1989. A multiple regression analysis was performed in which the natural logarithms of each state's annual crash counts were modeled as a function of state, calendar year, the natural logarithm of motorcycle registration counts, and a dummy • Table 1.
Motorcycle crashes per registered motorcycle in Nebraska artcl comparison states State
Helmet Law
Nebraska
None,1984-1988 Crashes 1,274 1,239 978 979 857 539 Allriders, 1989 Registrations 46,532 42,548 33,077 31,770 29,088 23,560 C/R 274 281 293 308 295 229
Statistic
1984
1985
19~6
1987
1988
t989
Iowa
None
Crashes 2,589 2,040 1,905 1,905 1,800 1,500 Registrations 183,687188,277 172,444 163,521 145,967 139,038 C/R 141 108 116 116 123 108
Kansas
Under18 years
Crashes Registrations C/R
1,835 1,681 1,644 1,534 1,274 1,189 83,744 78,739 73,890 69,532 04,724 61,419 219 213 222 221 197 194
North Dakota
Under 18 years
Crashes Registrations C/R
386 380 286 285 234 186 31,480 30,596 28,118 32,152 23,878 21,674 123 124 102 89 98 86
Oklahoma Under18years
Crashes 2,350 2,279 1,917 1,626 1,493 1,315 Registrations 150,963104,457 68,093 67,802 64,056 60,863 C/R 222 218 282 246 233 216
South Dakota
Crashes Registrations C/R
Under18 years
559 551 475 399 424 377 38,956 37,905 36.036 33,800 31,421 29,942 143 145 132 118 135 128
C/R,crashes/registrations÷ lO,O00.
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variable for Nebraska's helmet use law (coded 0 for all state and year combinations except Nebraska in 1989, which was coded 1). The regression accounted for 99.4% of the variance and estimated a significant (P < .05) 26% decline in motorcycle crashes associated with the law. Clinical Injury Study During the two-year study period, 671 persons were reported as injured to the Department of Roads in the two study counties. Of the reported injured, 286 (188 in 1988 and 98 in 1989) were transported by a participating ambulance service or died at the scene; 134 of the transported were admitted to the hospital or died in the ED. Autopsy reports and hospital records yielded injury descriptions for 279 (98%) of the 286 transported or fatally injured patients. Inpatient information was available on 127 (99%) of the 128 patients admitted (six died in the ED). Complete information on charges was available for 270 (95%) of the 284 patients transported (two died at the scene). Consistent with the statewide decline in motorcycle crashes, there were sharp declines between the two years in the number (and rates per 10,000 registrations) of reported injured, hospital transports (including the two patients who died at the scene), hospital admission, serious head injuries (AIS, 3 or higher), serious nonhead injuries (AIS, 3 or higher), and deaths (Table 2). All these declines were statistically significant, with the exception of Table 2.
Changes in number (and rates per 20,000 registrations) of persons injured, dispositions, and injuries in the study region Number of Persons (Rate) 1988 1989
Registrations Persons reported injured Ambulance transports Admissions or deaths Deaths Head injures (AIS ->3) Nonhead injuries (AfS _>3)
8,895 421 188 93 12 23 48
(473) (211 ) (1861 (13) (26) (54)
7,354 250 98 43 8 9 28
% Change in Rate
(340) (~33) (60) (8) (12) (38)
-28 -37 -43 -38 -54 -30
deaths alone. Despite the reductions in injured motorcyclists between the two years, the characteristics of the injured cyclists and the conditions under which they incurred their injuries were in large part the same (Table 3). The only statistically significant differences (P < .05) were an increase in helmet use and an increase in proper licensure among the injured motorcyclists who were known to have been driving. A summary by Injury Severity Score region of the injuries among the 279 injured motorcyclists transported to the study hospitals in 1988 through 1989 is given (Table 4). Most relevant to helmet use are injuries to the head. These data do not reveal a sharp change in the distribution of injuries before and after the helmet use law. The number of motorcyclists transported by ambulance with serious (AIS, 3 or higher) injury to the brain or cranium declined from 12% of the injured in 1988 to 10% in 1989. This 22% reduction in likelihood of serious brain injury and a corresponding increase in the relative frequency of serious injury to body regions other than the head, neck, and face are consistent with the anticipated effect of increased helmet use, but the effect was not statistically significant due to the small number of injured cyclists. It is noteworthy that there was no observable increase in the relative frequency of cervical-spine injury, although, again, the small number of injured cyclists keeps the year-to-year comparison from achieving statistical power. Stronger evidence of the likely effect of the helmet use law is provided by comparing head injuries among helmeted and unhe]meted cyclists for the two years combined. The percentage of injured motorcyclists with serious brain or cranium injuries was much lower among helmeted motorcyclists (5%) than among unhelmeted cyclists (14%). This statistically significant (P < .05) effect indicates a • Table 4.
Percent of raotorcyclists with indicated injuries in Douglas and Lancaster Counties before and after helmet use law 1988 (N = 187) AIS > 1 AIS _>3 N % N %
Table 3,
Comparison of the reported injured groups in the study region 1988 (N [] 421)
Mean age (yr) % Male % Drivers % Single-vehicle collisen accident % Wet conditions % Dark conditions % Brivers with licenses* % Helmet use
ISS Region 1989 (N = 250)
26 (SD, 9) 91 90
26 91 90
35 5 37 38 15
37 4 32 51 t 85t
(SO, 9)
* Rased on motorcycle drivers with known iicensure; 318 in 1988 and 186 in 1989. t Statistically significant at P< .01,
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Head and Neck Brain or cranium Neck Cervical spine Face Chest Abdominal Extremities Lower extremity Upper extremity External Injuries other than head, neck, or face
49 45 0 11 15 22 24 98 74 46 175 185
26 24 6 8 12 13 52 40 25 94 99
24 23 O 2 3 12 4 39 32 13 0 46
13 12 1 2 6 2 21 17 7 26
1989 (N = 92) AIS > 1 AIS > 3 N % N %
25 22 1 7 9 9 11 48 32 23 84 91
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27 24 1 8 10 10 12 52 35 25 91 99
10 9 1 1 3 4 3 22 16 7 1 26
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reduction of two thirds in serious injury to the head associated with helmet use. The number and types of severe head injuries that occurred each year are given (Table 5). Several types of injuries showed large declines. The average length of hospital stay per admission and disposition of admitted motorcyclists are given (Table 6). There was no statistically significant difference between the two years. The differences in charges and payment sources are shown (Table 7), There was no statistically significant difference in average charges per admission. However, the total acute medical charges decreased by $324,648 (38%) after implementation of the helmet use law, consistent with the overall declines in crashes and injuries after the law went into effect. Of the patients with known insurance status, 59% had private insurance, 34% had no insurance, and 7% had Medicaid or Medicare. Of the nearly $1.4 million charged over both years, 48% was either unpaid or paid by state funds. Table 5.
Specifictypesofs¢~ere head and ce~ical-spinei~ur~sinthestudyregion: 1988 and 1989 1988 Massive crush
1989
1
1
Brainstem or cerebeHar injury
10
4
Cerebral Contusion or hemorrhage Laceration or hematoma
21 13
5 4
Skull Vault fracture 8asi(ar fracture
7 12
5 3
5
3
Cervical fracture
Table 6.
Length of hospital stay, disposition, and organ donors 1988 iN : 82) Average length of stay (days) % Readmit~ed % Requiring rehabilitation Number of organ donors
1989 (N = 38)
7 (SD,8) 8 7 1
7 18 5 0
(SD,7)
Table 7.
Acute medical charges and payment sources (1989 dollars) 1988 Admission average 9,035-+12,025 Total 862,309 Collected from insurance 498,352 or patient Collected from Medicaid/Medicare 114,011 Uncollected 249,946
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1989
Tatal
12,725_+18,713 537,661 1,399,97(] 224,896 732,248 52 53,720 259,045
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167,731 12 508,991 36
DISCUSSION As expected from prior research, the incidence of motorcycle crashes and, more importantly, serious head injury declined sharply after Nebraska reinstated a mandatory helmet use law. Although there also were large reductions in serious injury to other body regions, the finding that injured riders were two thirds less likely to suffer serious brain or cranium injury if they wore helmets indicates that a large proportion of the reduction in crashes and serious head injury after the law was clue to the increased use of helmets. Other factors that may have contributed to the reduction in motorcycle crashes include a decrease in miles driven per registered motorcycle and a change in motorcycle rider risk characteristics. For example, the proportion of injured motorcycle operators without motorcycle licenses decreased after helmet use was required. This may be an additional benefit to mandatory helmet use through the reduction of "experimental" driving of borrowed motorcycles. The number of injured motorcyclists was too small to show statistically significant changes in injury distributions before and after the law, but the results suggested an approximate 20% reduction in head injuries. That reduction, if accurate, may have been limited by improper helmet use. Several accident descriptions of the transported patients stated that the helmet flew off during the crash. An observation study sponsored by the Nebraska Department of Motor Vehicles in 1989 (personal communication, Fred Zwonechek, Nebraska Office of Highway Sa{ety/Department of Motor Vehicles, 1989) showed that although 99% of motorcyclists were wearing helmets, one third of the helmets were improperly secured. Also, some helmet designs may allow the helmet to come off during a collision, even if properly secured. 49 The maximum effect of a helmet use law in preventing severe head injuries may not he realized unless the proper use of approved helmets is enforced. There have been allegations that helmet use might increase the likelihood of basilar fractures40 and cervical-spine injuries.]9, 41-43 Consistent with other clinical studies,iS,23, 28 the studies here showed no evidence to support these allegations. If anything, there was a decline in basilar fractures. The notion that helmet use would prolong care for severely injured individuals who would otherwise have been killed was not supported by the study-. The average length of hospital stay for injured and transported cyclists was similar for each year. An evaluation of Louisiana's helmet use law showed a decrease in length of stay, but that study included patients discharged from the ED.28 When hospital stay was analyzed only for admitted patients in the Louisiana study, as in the present study-, the I~
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length of stay was no different. This suggests that although total admissions decrease after the enactment of a helmet use law, the patients that are admitted are still severely injured, albeit with fewer head injuries. There was no statistically significant difference in average hospital charges to the admitted patients. Although this also appears to contradict the Louisiana study, which showed a decrease in medical care costs, that study included long-term medical costs in the analysis. When only ED and acute hospital costs were analyzed, as in our study, the average costs were similar. Again, this might indicate that the individual costs of acute care for severely injured motorcyclists, who were selected by our study design, are similar regardless of whether a severe head injury is present. The possibility that long-tema costs would be lowered after the enactment of a helmet use law was not assessed in our study. The total charges decreased by more than $324,000 (38%) as a result of fewer crashes and fewer admissions for those involved in crashes. Because the study represented 46% of the reported injured motorcyclists in the state, the total decrease in charges for the state may have been more than $700,000. If Rivara et al's estimate that acute hospitalization charges for injured motorcyclists amount to 60.5% of the total medical c o s t s , 11 then the helmet use law may have decreased total medical costs in the state by more than $1.1 million. Forty-eight percent of the total acute medical charges ($676,722) over both years were either unpaid or paid by governmerit funds. This percentage is not as large as that in other studi e s , 7-13 and may be due to the fact that our study population was a more inclusive representation of the general population than other studies. This still represents a large cost to society. The percentage of admitted patients requiring readmission or long-term rehabilitation was similar for both years. However, no motorcyclist known to be wearing a helmet required rehabilitative care. Head injuries are not the only significant source of hospital costs. Large reductions in medical costs could be realized if serious extremity injuries could be prevented or diminished. The medical charges of the 49 persons without severe head injuries but with severe extremity injuries amounted to more than $565,000 during the two years. The high severity of extremity injuries in motorcycle crashes has been well described;3,4.so,51 however, no totally effective protective measure has been developed. Our study design had some limitations. It provided information only on injured motorcyclists reported to the police or on the reported injured who were transported to a hospital by a study
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ambulance service. The difficulty of capturing all motorcycle injuries without ED-based surveillance was demonstrated in another study that indicated that only 39% of injured motorcyclists treated in the ED were identified as such by police reports. 52 Because the total number and types of less severe injuries are unknown, the true impact of the helmet use law on all injury rates (minor and severe) and individual costs cannot be described with certainty. Another limitation is the lack of information on motorcycle injuries in rural areas. The population of injured rural motorcyclists may differ from that of injured urban motorcyclists. Other studies have indicated that motor vehicle crashes in general are more severe 53 and result in higher mortality rates s¢ in rural areas than in urban areas. Also, people with similar injuries may have higher mortality rates in rural areas than in urban areas. 55
CONCLUSION Arguments against helmet use laws usually center around issues of personal freedom versus cost to society56-5a and claims that helmets cause certain injuries. After reinstatement of a helmet use law in Nebraska, there were fewer crashes, severe head injuries, and fatalities. During the year before and the year after the law, motorcyclists with helmets who were injured and transported to hospitals were significantly less likely to suffer serious head injuries than were motorcyclists without helmets. Medical costs due to motorcycle injuries may have decreased by more than $1 million. []
The authors thank James Manion, MD, for his thoughtful review of the article; Fred Zwonechek, Nebraska Department of Highway Safety; and Charlene Dubar, Nebraska Department of Health, for their assistance in obtaining data. They also thank Kathy Warren, RN, for her injury coding assistance and Suzanna Ettrich for her editorial assistance.
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42. Simpson DA, Blumbergs RD, CooterRD, et al: PontomedulJarytears and other gross brainstem injuries after vehicular accidents. J Trauma1989;29:1519q525. 43. Huston RL, SearsJ: Effect of protectivehelmet mass on head/neckdynamics. J BiomedEng 1981:103:18-23. 44. DobsonJL: The public cost of motorcycletrauma (letter). JAMA 1989;261:1149. 45. Webb HB: Compulsoryhelmets for motorcyclists? N EnglJ Mef11979;300:567. 46. Motorcycle IndustryCouncil, Inc: 1990MotorcadeStatisticalAnnuaL Irvine, California, MlCl, 1990. 47. AmericanAssociationfor Automotive Medicine: TheAbbreviatedlejury Scale1985 Revision, Arlington Heights, Illinois, AAAM, 1985. 48. US Departmentof Labor,Bureauof Labor Statistics,Washington, DC, 1990. 49. RichardsPG: Detachmentof crash helmets during motorcycleaccidents. BrMedJ 1984;228:758. 50. Jackson RD: A characteristictype of motorcyclefracture of the tibia. SouthMad J 1970;63:222-225. 51. FindlayJA: The motorcycletibia. Injury1972;4:75-78. 52. DrysdaleWF, KrausJF, Franti CE, at al: Injury patterns in motorcyclecollisions. J Trauma 1975;I 5:98-115. 53. US Departmentof Transportation, National HighwayTraffic Safety Administration: National AccidentSamplingSystem.Washington DC, NATSA,1986,Table 111-121. 54. BakerSP,Whitfield MS, O'Neil B: Geographicvariations in mortality from motor vehicle crashes. N EnglJ Med 1987;316:1384-1387. 55. Muefler BA, Rivara FP, BergmanAB: Urban-rural location and the risk of dying in a pedestrian-vehiclecelIection. J Trauma1988;28:91-94. 56. BakerSP: On lobbies, liberty, and the public good. Am J PublicHealth 1980;70:573-574. 57. TrunkeyDD: Helmetsfor motorcyclists. WestJMed1981;135:136. 58. NarayanRK: How manydeaths will it take? TexMeal1987;83:5-6.
Address for reprints: Robert L Muelleman, MD, University of Nebraska Medical Center, Section of Emergency Medicine, 600 South 42nd Street, Omaha, Nebraska 68198-1150.
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motorcycle helmets
M o t o r c y c l e Crash Injuries and Costs: Effect of a Reenacted Comprehensive Helmet Use Law From the Department of Emergency
Robert L Muelleman, MD, FACEP*
Study objectives: To document the effect of a reenacted comprehen-
Medical Services, University of
Edward J Mlinek, MD, FACEP*
sive helmet use law on injuries and fatalities.
Nebraska Medical Center;* and
Paul E Collicott, MD, FACSt
Design: Retrospective before-and-after analysis.
Department of Surgery, University of Nebraska College of Medicine, Omaha. "~ Receivedfor publication August 30, 1991. Revision received October 18,
Setting: Two urban counties representing 40% of Nebraska's population.
Participants: Six hundred seventy-one patients reported as injured to the Nebraska Department of Roads in the period from one year before through one year after the reenactment on January 1, 1989.
1991. Acceptedfor publication
Results: The helmet use law was temporally associated with a 26%
November 8, 1991.
decrease in the reported rate of motorcycle crashes in Nebraska compared with five other midwestern states. There were sharp declines in the number (and rates) of reported injured, hospital transports, hospital admissions, severe nonhead injuries, severe head injuries, and deaths. Serious head injuries (Abbreviated Injury Score, 3 or higher) decreased 22%. The percentage of injured motorcyclists with serious head injuries was significantly lower among the helmeted motorcyclists (5%) than among the unhelmeted cyclists (14%)for the two years combined.
Presented at the Societyfor Academic Emergency Medicine Annual Meeting in Washington, DC, May 1991. This work was supported by the Insurance Institutefor Highway
Conclusion: The reenactment of a helmet use law resulted in fewer crashes, fatalities, and severe head injuries. [Muelleman RL, Mlinek EJ, Collicott PE: Motorcycle crash injuries and costs: Effect of a reenacted comprehensive helmet use law. Ann Emerg Med March 1992;21:266-272.]
Safety.
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INTRODUCTION Motorcycle crashes resulted in more than 40,000 deaths and many more injuries in the United States during the 1980s. i-s The direct and indirect costs of motorcycle trauma are high. 6 Because many motorcyclists are uninsured, much of the cost for their medical care goes unpaid or is paid by government funds. 7-13 The effectiveness of motorcycle helmets, first noted in 1941,14 has been confirmed repeatedly,a J3, ls-26 as has the ability of comprehensive helmet use laws to increase helmet use. 27-31 In states without helmet use laws or with only partial helmet use laws, the death rate from head injuries is twice as high as in states with comprehensive laws. 32 During the 1970s, 26 states repealed or weakened their comprehensive laws, resulting in increased mortality22,23, 33,34 and cost22,23,35,36 from motorcycle crashes. Only four of those states reenacted a comprehensive law during the 1980s: Louisiana, Oregon, Texas, and Nebraska. Currently, 25 states (including the District of Columbia) have comprehensive helmet use laws, 23 have partial laws, and three have no laws requiring helmet use. 37 Opponents of helmet use laws have argued that they limit personal freedom. 38 Opponents have also claimed that the laws result in higher crash rates 39 and certain types of head 4°-¢2 and neck19,al,a3 injuries, as well as an increased cost to society resulting from the permanent disability of individuals who would have been killed if they had not worn helmets .44 Others lament the fact that fewer donor organs will be available if more motorcyclists wear helmets, as To counterbalance such arguments, recent proposed federal legislation (S 1007/HR 3925) threatens to reduce apportionment of federal aid highway funds to states that fail to require the use of motorcycle helmets as well as front seat safety belts for automobile occupants. As an added incentive, the legislation also offers motorcycle helmet and safety belt grants to certain states. The purpose of this study was to document the effects of a helmet use law on crash, fatality, and severe head injury rates and acute medical charges in Nebraska. An earlier law in Nebraska was repealed in 1977, and the new law went into effect on January 1, 1989. This study allows not only timely evaluation of the reenacted law for Nebraska but also provides new information for the continuing political debate over comprehensive helmet use laws in other states.
MATERIALS AND METHODS The study used a retrospective, before-and-after design. For one year before and one year after the effective date of the new law, the study gathered data about fatalities, specific injuries, and
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costs from motorcycle crashes in two urban Nebraska counties (a clinical injury study). In addition, statewide motorcycle crash rates were examined for Nebraska and several comparison states for five years before and one year after the law's effective date (a crash rate study). C r a s h R a t e S t u d y The number of motorcycle registrations and crashes in 1984 through 1989 for Nebraska and five comparison states was obtained from the Motorcycle Statistical Annual.46 Iowa, Kansas, Oklahoma, South Dakota, and North Dakota were chosen as comparison states because they are in the same region and did not change their helmet use laws during the time period of 1984 through 1989; none has a comprehensive helmet use law. Clinical Injury Study Data were obtained from four sources: crash and registration data for the two counties from the Nebraska Department of Motor Vehicles and Department of Roads, prehospital data from ambulance and medical helicopter services, hospital data from participating hospitals, and autopsy data from county coroners. The two study counties were Douglas and Lancaster. In 1988, the two counties had a combined population of 630,000, representing 40% of the state's population. Douglas County has eight acute care hospitals with emergency departments, and Lancaster County has three. All 11 hospitals agreed to participate in the study after assurance that the medical information would be provided anonymously. Douglas County has two self-designated Level I trauma centers, two major ambulance services that are advanced life support fire department-based systems, and two medical helicopter services. Lancaster County has one Level II (American College of Surgeons verification) trauma center, one major ambulance service that is an advanced lifed support private system, and no helicopter services. Patients were included in the two-county, clinical injury study if the crash was reported to the Department of Roads, the injury was sustained in a motorcycle crash in one of the study counties, and they were transported by a participating ambulance or helicopter service to a participating hospital. Crashes reported to the Department of Roads were those that had been reported to the police after occurring on a public road and involved an injury, fatality, or at least $500 in property damage. Hospital records in the two counties were incomplete with regard to the cause of injuries (ie, motorcycle crash or other injury mechanism). Therefore, case finding began with lists of all motorcyclists reported to the Department of Roads as injured in the study counties. These lists also contained information on II~
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hehnet use, age, and gender; driver's motorcycle licensure; date, time, and location of the crash; and road surface and light conditions. The lists of injured motorcyclists from the Department of Roads were matched with prehospital information from the ambulance services. The private ambulance service in Lancaster County and both helicopter services computerized all transport information locally and were able to determine which of the reportedly injured motorcyclists they had transported in both years. Copies of their transport sheets were provided for documentation. The public ambulance services in Douglas County sent their transport sheets to the state department of health, where the information was computerized without patients' names or, in 1989, information about the cause of injury. The 1988 motorcycle-related transport sheets were located manually and then matched to the list of injured motorcyclists by date and location to identify the 1988 study patients in Douglas County. In 1989, the Douglas County ambulance services began coding transports by cause of injury (E codes), and the Department of Health provided a computer-generated list of all motorcycle-related transports at the end of that year. In addition, copies of the 1989 transport sheets were made for the study before the originals were sent to the department. The combination of copied transport sheets and any other motorcycle-related transports of patients on the Department of Health list (matched to the Department of Roads' list by date and location) identified the 1989 study patients in Douglas County. Information from the transport sheets was used to identify receiving hospitals. The ambulance services also provided additional information about helmet use and whether the injured motorcyclist was the driver or passengeL Once it was determined to which hospitals the patients had been transported, a list of patients with assigned code numbers was periodically sent to each hospital. For privacy reasons, the hospital provided information identified by the patient's code number. The hospital data included disposition, length of hospitalization, discharge disposition, evidence of readmission, organ donor status, specific injuries, insurance status, acute medical charges, and amount collected. The hospitals also provided information about helmet use. If there was a discrepancy in the helmet use reported by the Department of Roads, the ambulance service, and the receiving hospital, helmet use was coded as unknown. Injuries located from the hospital data and the coroner's reports were described and coded by one trauma nurse coordinator familiar with the Abbreviated Injury Scale (AIS) (1985 version). 47
Costs in this study included only acute medical charges. Prehospital charges, physician fees, readmission costs, and rehabilitation costs were not obtained. Charges in 1988 were converted to 1989 dollars by muhiplying by 1.085 to reflect the 8.5% inflation of medical charges from 1988 to 1989. ¢8 Because police reporting of crashes is incomplete, it is likely that some injured motorcyclists treated at the study hospitals were missed by the study design in both years. However, a sixmonth prospective ED surveillance during the second year of the study indicated that the design captured 100% of the deaths, 100% of the seriously head injured patients (AIS, 3 or higher), 92% of the seriously nonhead injmed patients (AIS, 3 or higher), and 83% of the admissions during the surveillance period. Fiftyfive percent of the less-than-seriously injured patients (AIS, less than 3) were missed by the study design. Comparison of crash rates was made by multiple regression analysis. Comparison of proportions was measured by Z2 goodness-of-fit tests. P < .05 was considered statistically significant.
RESULTS S t a t e C r a s h R a t e s Counts of motorcycle crashes and registrations during 1984 through 1989 in Nebraska and the five comparison states are given (Table 1). Both crashes and registrations declined in all states during these years, but there was a sharp decrease in crashes per 10,000 registrations in Nebraska coincident with the reinstatement of mandatory helmet use in 1989. A multiple regression analysis was performed in which the natural logarithms of each state's annual crash counts were modeled as a function of state, calendar year, the natural logarithm of motorcycle registration counts, and a dummy • Table 1.
Motorcycle crashes per registered motorcycle in Nebraska artcl comparison states State
Helmet Law
Nebraska
None,1984-1988 Crashes 1,274 1,239 978 979 857 539 Allriders, 1989 Registrations 46,532 42,548 33,077 31,770 29,088 23,560 C/R 274 281 293 308 295 229
Statistic
1984
1985
19~6
1987
1988
t989
Iowa
None
Crashes 2,589 2,040 1,905 1,905 1,800 1,500 Registrations 183,687188,277 172,444 163,521 145,967 139,038 C/R 141 108 116 116 123 108
Kansas
Under18 years
Crashes Registrations C/R
1,835 1,681 1,644 1,534 1,274 1,189 83,744 78,739 73,890 69,532 04,724 61,419 219 213 222 221 197 194
North Dakota
Under 18 years
Crashes Registrations C/R
386 380 286 285 234 186 31,480 30,596 28,118 32,152 23,878 21,674 123 124 102 89 98 86
Oklahoma Under18years
Crashes 2,350 2,279 1,917 1,626 1,493 1,315 Registrations 150,963104,457 68,093 67,802 64,056 60,863 C/R 222 218 282 246 233 216
South Dakota
Crashes Registrations C/R
Under18 years
559 551 475 399 424 377 38,956 37,905 36.036 33,800 31,421 29,942 143 145 132 118 135 128
C/R,crashes/registrations÷ lO,O00.
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variable for Nebraska's helmet use law (coded 0 for all state and year combinations except Nebraska in 1989, which was coded 1). The regression accounted for 99.4% of the variance and estimated a significant (P < .05) 26% decline in motorcycle crashes associated with the law. Clinical Injury Study During the two-year study period, 671 persons were reported as injured to the Department of Roads in the two study counties. Of the reported injured, 286 (188 in 1988 and 98 in 1989) were transported by a participating ambulance service or died at the scene; 134 of the transported were admitted to the hospital or died in the ED. Autopsy reports and hospital records yielded injury descriptions for 279 (98%) of the 286 transported or fatally injured patients. Inpatient information was available on 127 (99%) of the 128 patients admitted (six died in the ED). Complete information on charges was available for 270 (95%) of the 284 patients transported (two died at the scene). Consistent with the statewide decline in motorcycle crashes, there were sharp declines between the two years in the number (and rates per 10,000 registrations) of reported injured, hospital transports (including the two patients who died at the scene), hospital admission, serious head injuries (AIS, 3 or higher), serious nonhead injuries (AIS, 3 or higher), and deaths (Table 2). All these declines were statistically significant, with the exception of Table 2.
Changes in number (and rates per 20,000 registrations) of persons injured, dispositions, and injuries in the study region Number of Persons (Rate) 1988 1989
Registrations Persons reported injured Ambulance transports Admissions or deaths Deaths Head injures (AIS ->3) Nonhead injuries (AfS _>3)
8,895 421 188 93 12 23 48
(473) (211 ) (1861 (13) (26) (54)
7,354 250 98 43 8 9 28
% Change in Rate
(340) (~33) (60) (8) (12) (38)
-28 -37 -43 -38 -54 -30
deaths alone. Despite the reductions in injured motorcyclists between the two years, the characteristics of the injured cyclists and the conditions under which they incurred their injuries were in large part the same (Table 3). The only statistically significant differences (P < .05) were an increase in helmet use and an increase in proper licensure among the injured motorcyclists who were known to have been driving. A summary by Injury Severity Score region of the injuries among the 279 injured motorcyclists transported to the study hospitals in 1988 through 1989 is given (Table 4). Most relevant to helmet use are injuries to the head. These data do not reveal a sharp change in the distribution of injuries before and after the helmet use law. The number of motorcyclists transported by ambulance with serious (AIS, 3 or higher) injury to the brain or cranium declined from 12% of the injured in 1988 to 10% in 1989. This 22% reduction in likelihood of serious brain injury and a corresponding increase in the relative frequency of serious injury to body regions other than the head, neck, and face are consistent with the anticipated effect of increased helmet use, but the effect was not statistically significant due to the small number of injured cyclists. It is noteworthy that there was no observable increase in the relative frequency of cervical-spine injury, although, again, the small number of injured cyclists keeps the year-to-year comparison from achieving statistical power. Stronger evidence of the likely effect of the helmet use law is provided by comparing head injuries among helmeted and unhe]meted cyclists for the two years combined. The percentage of injured motorcyclists with serious brain or cranium injuries was much lower among helmeted motorcyclists (5%) than among unhelmeted cyclists (14%). This statistically significant (P < .05) effect indicates a • Table 4.
Percent of raotorcyclists with indicated injuries in Douglas and Lancaster Counties before and after helmet use law 1988 (N = 187) AIS > 1 AIS _>3 N % N %
Table 3,
Comparison of the reported injured groups in the study region 1988 (N [] 421)
Mean age (yr) % Male % Drivers % Single-vehicle collisen accident % Wet conditions % Dark conditions % Brivers with licenses* % Helmet use
ISS Region 1989 (N = 250)
26 (SD, 9) 91 90
26 91 90
35 5 37 38 15
37 4 32 51 t 85t
(SO, 9)
* Rased on motorcycle drivers with known iicensure; 318 in 1988 and 186 in 1989. t Statistically significant at P< .01,
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Head and Neck Brain or cranium Neck Cervical spine Face Chest Abdominal Extremities Lower extremity Upper extremity External Injuries other than head, neck, or face
49 45 0 11 15 22 24 98 74 46 175 185
26 24 6 8 12 13 52 40 25 94 99
24 23 O 2 3 12 4 39 32 13 0 46
13 12 1 2 6 2 21 17 7 26
1989 (N = 92) AIS > 1 AIS > 3 N % N %
25 22 1 7 9 9 11 48 32 23 84 91
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27 24 1 8 10 10 12 52 35 25 91 99
10 9 1 1 3 4 3 22 16 7 1 26
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reduction of two thirds in serious injury to the head associated with helmet use. The number and types of severe head injuries that occurred each year are given (Table 5). Several types of injuries showed large declines. The average length of hospital stay per admission and disposition of admitted motorcyclists are given (Table 6). There was no statistically significant difference between the two years. The differences in charges and payment sources are shown (Table 7), There was no statistically significant difference in average charges per admission. However, the total acute medical charges decreased by $324,648 (38%) after implementation of the helmet use law, consistent with the overall declines in crashes and injuries after the law went into effect. Of the patients with known insurance status, 59% had private insurance, 34% had no insurance, and 7% had Medicaid or Medicare. Of the nearly $1.4 million charged over both years, 48% was either unpaid or paid by state funds. Table 5.
Specifictypesofs¢~ere head and ce~ical-spinei~ur~sinthestudyregion: 1988 and 1989 1988 Massive crush
1989
1
1
Brainstem or cerebeHar injury
10
4
Cerebral Contusion or hemorrhage Laceration or hematoma
21 13
5 4
Skull Vault fracture 8asi(ar fracture
7 12
5 3
5
3
Cervical fracture
Table 6.
Length of hospital stay, disposition, and organ donors 1988 iN : 82) Average length of stay (days) % Readmit~ed % Requiring rehabilitation Number of organ donors
1989 (N = 38)
7 (SD,8) 8 7 1
7 18 5 0
(SD,7)
Table 7.
Acute medical charges and payment sources (1989 dollars) 1988 Admission average 9,035-+12,025 Total 862,309 Collected from insurance 498,352 or patient Collected from Medicaid/Medicare 114,011 Uncollected 249,946
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1989
Tatal
12,725_+18,713 537,661 1,399,97(] 224,896 732,248 52 53,720 259,045
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167,731 12 508,991 36
DISCUSSION As expected from prior research, the incidence of motorcycle crashes and, more importantly, serious head injury declined sharply after Nebraska reinstated a mandatory helmet use law. Although there also were large reductions in serious injury to other body regions, the finding that injured riders were two thirds less likely to suffer serious brain or cranium injury if they wore helmets indicates that a large proportion of the reduction in crashes and serious head injury after the law was clue to the increased use of helmets. Other factors that may have contributed to the reduction in motorcycle crashes include a decrease in miles driven per registered motorcycle and a change in motorcycle rider risk characteristics. For example, the proportion of injured motorcycle operators without motorcycle licenses decreased after helmet use was required. This may be an additional benefit to mandatory helmet use through the reduction of "experimental" driving of borrowed motorcycles. The number of injured motorcyclists was too small to show statistically significant changes in injury distributions before and after the law, but the results suggested an approximate 20% reduction in head injuries. That reduction, if accurate, may have been limited by improper helmet use. Several accident descriptions of the transported patients stated that the helmet flew off during the crash. An observation study sponsored by the Nebraska Department of Motor Vehicles in 1989 (personal communication, Fred Zwonechek, Nebraska Office of Highway Sa{ety/Department of Motor Vehicles, 1989) showed that although 99% of motorcyclists were wearing helmets, one third of the helmets were improperly secured. Also, some helmet designs may allow the helmet to come off during a collision, even if properly secured. 49 The maximum effect of a helmet use law in preventing severe head injuries may not he realized unless the proper use of approved helmets is enforced. There have been allegations that helmet use might increase the likelihood of basilar fractures40 and cervical-spine injuries.]9, 41-43 Consistent with other clinical studies,iS,23, 28 the studies here showed no evidence to support these allegations. If anything, there was a decline in basilar fractures. The notion that helmet use would prolong care for severely injured individuals who would otherwise have been killed was not supported by the study-. The average length of hospital stay for injured and transported cyclists was similar for each year. An evaluation of Louisiana's helmet use law showed a decrease in length of stay, but that study included patients discharged from the ED.28 When hospital stay was analyzed only for admitted patients in the Louisiana study, as in the present study-, the I~
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length of stay was no different. This suggests that although total admissions decrease after the enactment of a helmet use law, the patients that are admitted are still severely injured, albeit with fewer head injuries. There was no statistically significant difference in average hospital charges to the admitted patients. Although this also appears to contradict the Louisiana study, which showed a decrease in medical care costs, that study included long-term medical costs in the analysis. When only ED and acute hospital costs were analyzed, as in our study, the average costs were similar. Again, this might indicate that the individual costs of acute care for severely injured motorcyclists, who were selected by our study design, are similar regardless of whether a severe head injury is present. The possibility that long-tema costs would be lowered after the enactment of a helmet use law was not assessed in our study. The total charges decreased by more than $324,000 (38%) as a result of fewer crashes and fewer admissions for those involved in crashes. Because the study represented 46% of the reported injured motorcyclists in the state, the total decrease in charges for the state may have been more than $700,000. If Rivara et al's estimate that acute hospitalization charges for injured motorcyclists amount to 60.5% of the total medical c o s t s , 11 then the helmet use law may have decreased total medical costs in the state by more than $1.1 million. Forty-eight percent of the total acute medical charges ($676,722) over both years were either unpaid or paid by governmerit funds. This percentage is not as large as that in other studi e s , 7-13 and may be due to the fact that our study population was a more inclusive representation of the general population than other studies. This still represents a large cost to society. The percentage of admitted patients requiring readmission or long-term rehabilitation was similar for both years. However, no motorcyclist known to be wearing a helmet required rehabilitative care. Head injuries are not the only significant source of hospital costs. Large reductions in medical costs could be realized if serious extremity injuries could be prevented or diminished. The medical charges of the 49 persons without severe head injuries but with severe extremity injuries amounted to more than $565,000 during the two years. The high severity of extremity injuries in motorcycle crashes has been well described;3,4.so,51 however, no totally effective protective measure has been developed. Our study design had some limitations. It provided information only on injured motorcyclists reported to the police or on the reported injured who were transported to a hospital by a study
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ambulance service. The difficulty of capturing all motorcycle injuries without ED-based surveillance was demonstrated in another study that indicated that only 39% of injured motorcyclists treated in the ED were identified as such by police reports. 52 Because the total number and types of less severe injuries are unknown, the true impact of the helmet use law on all injury rates (minor and severe) and individual costs cannot be described with certainty. Another limitation is the lack of information on motorcycle injuries in rural areas. The population of injured rural motorcyclists may differ from that of injured urban motorcyclists. Other studies have indicated that motor vehicle crashes in general are more severe 53 and result in higher mortality rates s¢ in rural areas than in urban areas. Also, people with similar injuries may have higher mortality rates in rural areas than in urban areas. 55
CONCLUSION Arguments against helmet use laws usually center around issues of personal freedom versus cost to society56-5a and claims that helmets cause certain injuries. After reinstatement of a helmet use law in Nebraska, there were fewer crashes, severe head injuries, and fatalities. During the year before and the year after the law, motorcyclists with helmets who were injured and transported to hospitals were significantly less likely to suffer serious head injuries than were motorcyclists without helmets. Medical costs due to motorcycle injuries may have decreased by more than $1 million. []
The authors thank James Manion, MD, for his thoughtful review of the article; Fred Zwonechek, Nebraska Department of Highway Safety; and Charlene Dubar, Nebraska Department of Health, for their assistance in obtaining data. They also thank Kathy Warren, RN, for her injury coding assistance and Suzanna Ettrich for her editorial assistance.
REFERENCES 1. National HighwayTraffic Safety Administration: FatalAccidentReportingSystem: 1989 Washington, DC. US Departmentof Transportation, publication DOT-HS889-507, 1990. 2. DeanerRM, FitchettVH: Motorcycletrauma. J Trauma1975;15:678-68t. 3. HaddadJP, EchaveV, Brown RA, et ah Motorcycleaccidents:A review of 77 patients treated in a three-month period. J Trauma1976;16:550-557. 4. Zettas JP, Zettas P, ThanasophonB: Injury patterns in motorcycleaccidents. J Trauma 1979;19:833-836. 5. Andrew TA: A six-month review of motorcycleaccidents. Injury1978;10:317-320. 5. Rice DP, Mackensie EJ, etah Costof Injury for the United States:A Reportto Congress.San Francisco, InstTtutefor Health and Aging, University of California,The Johns Hopkins University, and Baltimore, Maryland, Iniury PreventionCenter, 1989, 7. Bach BR, Wyman ET: Financial charges of hospitalizedmotorcyclistsat the Massachusetts General Hospital. J Trauma1986;26:343-347. ~1~
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Address for reprints: Robert L Muelleman, MD, University of Nebraska Medical Center, Section of Emergency Medicine, 600 South 42nd Street, Omaha, Nebraska 68198-1150.
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