Validating the Functional Capacity Index as a measure of outcome following blunt multiple trauma.

BACKGROUND: The validity of the Functional Capacity Index (FCI) is evaluated by examining its distributional characteristics, its correlation with other well-known measures of outcome and its ability to discriminate among persons with injuries of varying type and severity. METHODS: A telephone survey which included the FCI and the SF-36 was administered 1 year post-injury to 1240 blunt trauma patients discharged from 12 trauma centers. A subsample of 656 patients also completed the Sickness Impact Profile (SIP) by mail. RESULTS: FCI scores correlated well with the physical health subscores of the SIP and SF-36. They also correlated well with self-reported change in health status and return to work. The FCI, when compared to either the SF-36 or the SIP, however, appears to discriminate better among patients according to the presence and severity of head trauma. CONCLUSIONS: While further testing of the FCI is needed, it holds promise as a preference based measure for assessing the physical impact of trauma.

The development of the Functional Capacity Index.

OBJECTIVE: This paper describes the development of the Functional Capacity Index (FCI) and compares it to the Abbreviated Injury Scale (AIS) and the Injury Impairment Scale (IIS). METHODS: The FCI maps 1990 AIS injury descriptions into scores that reflect expected levels of reduced functional capacity at 1 year after injury. Its development involved three steps. First, an expert clinical panel identified 10 relevant dimensions of function and defined levels of capacity within each dimension. A group of 114 individuals then rated the relative severity of different levels of function in terms of their impact on daily living. The third step involved clinical experts assigning FCI scores to AIS '90 injury descriptions based on their knowledge of the likely 1-year consequences associated with each injury. As a first step in validating the FCI, 1 year postinjury levels of impairment (based on range of motion and strength) were correlated with FCI, IIS, and AIS scores derived for 301 patients with severe lower extremity fractures. RESULTS: Consistency of FCI scores derived within and across dimensions of function argue for the conceptual integrity of the index. Non-zero FCI scores were assigned to only 26% of the 1,272 AIS injury descriptions, indicating that, for most of the injuries in the AIS dictionary, very little or no residual impairment is expected for the average person at 1 year. FCI scores derived for 301 patients with lower extremity fractures ranged from 0 to 63 (out of a possible 100 points). A modest correlation was found between FCI scores and actual levels of impairment observed at 1 year. Compared with the AIS and the IIS, the FCI appeared to discriminate somewhat better among different levels of function. CONCLUSIONS: Although further empirical validation of the FCI is essential before it can be broadly applied, its development represents an important first step in the generation of an AIS-based measure of expected functional outcome. Its validation is encouraged across a variety of settings and injury types.

Long-term consequences of head injury.

This study was undertaken to determine the long-term consequences of head injury resulting from police reported tow-away motor vehicle crashes in the U.S. in 1993. The results are presented in terms of the Functional Capacity Index (FCI), which quantifies the relative functional capacity of a previously healthy adult 1 year postinjury, and Life-years Lost to Injury (LLI), defined as the FCI value times the injured person's life expectancy. FCI values vary from 0 for no effect to 1.0 for complete loss of function. Total LLI is indicative of the effect on society, and average LLI represents the effect of an injury on an "average" individual in the injured population. The results show that 1.7 times as many people with a brain injury resulting from a motor vehicle crash die than survive, and the Life-years Lost to Death are 1.8 times greater for these fatalities than the Life-years Lost to Injury for the surviving population. The injuries with the greatest FCI for survivors were unconsciousness, brain stem, and cerebrum injuries, all with FCI values at or near 1.0. The average LLI for these injury categories were 44.4, 45.1, and 42.8 years, respectively. The total LLI for these injuries were 57,843, 18,364, and 11,725 years, respectively. The principal conclusion is that motor vehicle related head injuries continue to have major consequences on the injured individuals, and considerable effect on society as a whole.

Crash costs and safety investment.

Injury crashes cost society more than $34 billion annually. Expending up to $2.3 million to prevent one fatal crash appears to be rational public policy, although the crash costs society only $500,000. Prevention of severe, nonfatal head and spinal cord injuries warrants even larger expenditures. The estimated rational investment to prevent an average nonfatal injury crash is $22,000, while society's cost is $8,000. Rational investment levels for increased safety are estimated by summing the amount individuals typically pay for small increases in their safety and the cost the rest of society bears when someone is killed or injured, including transfer payments.