May 1996, Vol. 30, No. 3

Injuries are a serious public health problem. During 1994, injury caused the deaths of 3,791 persons in Missouri. That same year, considering all hospitalizations, emergency department visits, outpatient surgery, and observations co mbined, more than 1 out of 10 Missourians were treated for nonfatal injury, with 46,323 cases severe enough to be hospitalized. There is an unknown number of other, usually less serious, injuries treated in physician offices, first aid centers, or at home , etc. (See Chart 1).

Prior to 1993, cause-of-death codes on death certificate data were the only reliable source of information available regarding the incidence of injury in Missouri. Considering the large numbers of hospitalizations and especially emergency department vi sits for injury, fatal injuries were only the "tip of the iceberg", as Chart 1 shows. While in years prior to 1993 hospital discharge records had been collected for inpatients treated in Missouri, external cause of injury (E-code) data were not required a nd were infrequently reported. Before 1993, no more than 40 percent of hospital discharge records of persons treated for injury contained an E-code. Until 1993, complete information was not systematically collected statewide from emergency departments or outpatient surgery clinics. The Patient Abstract System (PAS) was implemented by the Missouri Department of Health at the beginning of 1993. The PAS is a mandatory reporting system, gathering data from almost every hospital and ambulatory surgery facility in Missouri. Data from medical records of all persons hospitalized as inpatients or treated as outpatients (emergency department, outpatient surgery, observation, and diagnostic imaging) are reported. PAS records of every patient diagnosed as injured are required to state the external cause of injury as an E-code from the ICD-9-CM diagnostic manual.1 In 1994, more than 9 out of 10 patient records with injury contained a valid E-code. Records of death from injury always state the external cause of injury code.

Information from both death records and PAS are reported in Table 1. Cause of injury categories are equivalent to those used in the National Center for Health Statistics, "Interim Matrix Table for E-coded Injury Mortality Data, March 7, 1996." Categori es for motor vehicle nontraffic, unarmed fight or brawl, and rape were added since these occur frequently among nonfatal injuries and/or are of concern.

Unintentional, suicidal and assaultive injuries are all three among the top ten leading causes of death in Missouri and nationwide. About 6.8 percent of all deaths in Missouri during 1994 resulted from injury. Among those injury-related deaths, 61 perc ent were classified as accidental or unintentional, while almost one in five was self-inflicted and one in six was assault related. Motor vehicle traffic crashes were responsible for 31.2 percent of all injury fatalities, and caused 51.0 percent of uninte ntional deaths by injury in Missouri during 1994. Gunshot (unintentional, suicide, and homicide) was the second leading cause of death by injury, accounting for 26.6 percent of injury fatalities recorded in the state that year. Injury is the single most f requent cause of premature death. In 1994, of all deaths of Missouri residents under the age of 35, fully 51.7 percent died of injury.2

Serious nonfatal injuries, those requiring hospitalization, are most often the result of falls. During 1994, falls accounted for 43.2 percent of all inpatient episodes caused by injury. The second leading cause of serious nonfatal injury, at 16.7 perce nt, was motor vehicle crashes. Poisonings by foodstuffs, chemicals, gases or medications were responsible for 10.3 percent of injury related hospitalizations. Over 85 percent of injury-related hospitalizations were unintentional. Self-inflicted injuries r equiring hospitalization outnumbered assaults (7.1 percent vs. 5.5 percent, respectively).

In the Patient Abstract System, 94 percent of outpatient records of treatment for injury originate in emergency departments. Outpatient surgery accounts for 3 percent, observation for 2 percent, and 1 percent of outpatient visits are for diagnostic ima ging (CAT scans, MRIs, etc.).

As shown in Table 1, almost one-fourth (23.5 percent) of injured patients treated and released on an outpatient basis had suffered falls. Other common reasons for outpatient treatment of injury are cuts, traffic crashes, and being struck by an object. The "Other" category of outpatient injury treatment includes overexertion, animal and insect bites, scalds, caught between objects, and pedal cycle incidents. Nearly 95 percent of outpatient injury encounters were unintentional, while assaults were second with 4.2 percent.

Population-based rates of injury-related deaths and medical treatments are displayed in Chart 2. The vertical scale is logarithmic. The rate of death by injury for males is always greater than the rate for females. All three rates of injury- death, hos pitalization and outpatient care-decline somewhat between the ages of 5 and 14, then rise during the teenage years for both males and females. From early adulthood to retirement age at 65, injury rates for men reduce slowly, but are always higher than the rates for women during these years in the work force. Increases in injury rates are found for both men and women after age 65. In the 65-74 age group, injury rates increase more dramatically among women than among men, primarily due to falls. Within the elderly population, aged 65 and over, rates of nonfatal injuries among women overtake and remain higher than the rates for men.

Injuries are costly. Direct medical care, rehabilitation expenses, long-term disability, losses in productivity and earnings, and survivor benefits are all significant costs of injury.3 Programs that work to reduce the risk of injury are not only cost- effective, but also serve to safeguard and enhance the quality of life for all Missourians.

The advent of the Patient Abstract System allows a more complete picture of the incidence of injury in Missouri. Reasonably accurate measurements of nonfatal, yet serious, injuries are now possible. Quantitative studies assessing the magnitude and scop e of injury in Missouri are important. Information from the Patient Abstract System is of great value, for example, in both developing and evaluating prevention strategies, safety education and awareness programs, highway safety interventions, and efforts to reduce workplace injury.

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