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Epidemiology of traumatic and ischemic brain injuries. G. Citerio Rianimazione – H San Gerardo – Monza (Mi). Epidemiology. Epidemiology is the “study of the distribution and determinants of disease frequency” Two elements: Distribution (mortality, prevalence, trends)
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Epidemiology of traumatic and ischemic brain injuries G. Citerio Rianimazione – H San Gerardo – Monza (Mi)
Epidemiology • Epidemiology is the “study of the distribution and determinants of disease frequency” • Two elements: • Distribution (mortality, prevalence, trends) • Determinants (predisposing conditions and risk factors)
Incidence of traumatic brain injury (TBI). Using national data for 1995-1996, the CDC estimates that TBIs have this impact in the United States each year: • 1 million people are treated and released from hospital emergency departments • 230,000 people are hospitalized and survive • 50,000 people die
TBI incidence rate Using preliminary hospitalization and mortality data collected from 12 states during 1995-1996, CDC finds: • The average TBI incidence rate (combined hospitalization and mortality rate) is 95 per 100,000 population. Twenty-two percent of people who have a TBI die from their injuries.
TBI risk factors, and causes • The risk of having a TBI is especially high among adolescents, young adults, and people older than 75 years of age. • For persons of all ages, the risk of TBI among males is twice the risk among females. • The leading causes of TBI are motor vehicle crashes, violence, and falls. Nearly two-thirds of firearm-related TBIs are classified as suicidal in intent.
F 16 14 12 M 10 8 6 4 2 % 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 yrs Age and sex NL MI 97-98
80 70 60 50 40 30 20 10 0 FAVOURABLE UNFAVOURABLE Age and outcome p 0.0001
350 Unfavourable O. 300 Favourable O. 42% 250 200 150 100 56% 50 p 0.0001 0 Male Female mean age 38 21 mean age 48 23 p 0.0001 Sex and outcome
TBI risk factors, and causes • The leading causes of TBI vary by age: falls are the leading cause of TBI among persons aged 65 years and older, whereas transportation leads among persons aged 5 to 64 years. • The outcome of these injuries varies greatly depending on the cause: 91% of firearm-related TBIs resulted in death, but only 11% of fall-related TBIs are fatal.
3% 7% 2% 11% 5% 62% 10% Causes Road traffic accident Pedestrian Fall/Precipitation Domestic Sport Work Assault NL MI 97-98
Outcomes divided by cause Fall/Precipitation Favourable 48% Work Unfavourable 41% Domestic 72% Sport 88% Assault 80% Road traffic accident 39% Pedestrian 57% 0 50 100 150 200 250 300 p 0.0001
3% 7% 19% 71% NL MI 97-98 A. Prior good health B. Mild to moderate limitation of activity (chronic disease) C. Serious but not incapacitating restriction of activity (chronic disease) D. Restriction of activity (chronic disease) Chronic health evaluation Knaus WA, Zimmerman JE, Wagner DP et al: Apache-acute physiology and chronic health evaluation: a physiologically based classification system. Crit Care Med 1981; 9:591-597
350 UNFAV.OUTCOME 300 FAV.OUTCOME 36% 250 200 150 100 59% 79% 50 86% 0 A B C D Chronic health evaluation p 0.0001 • Prior good health; B. Mild to moderate limitation of activity; • C. Serious but not incapacitating restriction of activity D. Restriction of activity
There was a 22% decline in the TBI-related death rate from 24.6/100,000 U.S. residents in 1979 to 19.3/100,000 in 1992. Firearm-related rates increased 13% from 1984 through 1992, undermining a 25% decline in motor vehicle-related rates for the same period. Firearms surpassed motor vehicles as the largest single cause of death associated with traumatic brain injury in the United States in 1990.
Incidence and prevalence of TBI-related disability. Based on national TBI incidence data and preliminary data from the Colorado TBI Registry that describe TBI-related disability in 1996-1997, CDC estimates the following: • Each year more than 80,000 Americans survive a hospitalization for traumatic brain injury but are discharged with TBI-related disabilities. • 5.3 million Americans are living today with a TBI-related disability.
There are many kinds of impairments that may occur as a result of TBI. These injuries may impair: • cognition -- concentration, memory, judgment, and mood • movement abilities -- strength, coordination, and balance • sensation -- tactile sensation and special senses such as vision • TBI sometimes results in seizure disorders (epilepsy). About 1 percent of persons with severe TBI survive in a state of persisting unconsciousness.
There is no way to describe fully the human costs of traumatic brain injury: the burdens borne by those who are injured and their families. • Only a few analyses of the monetary costs of these injuries are available, including the following estimate (lifetime cost of all brain injuries occurring in the United States in 1985): • Direct annual expenditures $ 4.5 billion • Indirect annual costs $33.3 billion • Total costs $37.8 billion
Disability in young people and adults one year after head injury: prospective cohort studyS Thornhill, GM Teasdale, GD Murray, J McEwen, CW Roy, KI Penny BMJ 2000;320:1631-1635 ( 17 June )
Disability in young people and adults one year after head injury: prospective cohort studyS Thornhill, GM Teasdale, GD Murray, J McEwen, CW Roy, KI Penny BMJ 2000;320:1631-1635 ( 17 June )
Primary prevention Primary prevention of TBI is an important goal of public health efforts. Accomplishing this goal requires attention to each of the major external causes of these injuries: • transportation, • violence, • and falls.
1. Transportation Transportation crashes are the leading cause of TBI-associated death among women and persons under 15 years of age. Fortunately, the rate of TBI-associated death due to transportation crashes has decreased approximately 40 percent since 1980.
1. Transportation This drop is likely because of a combination of factors: - an increase in seat belt and child safety seat use, - an increase in the number of vehicles equipped with air bags, - and a decrease in the incidence of driving while intoxicated. These positive changes should receive continued support.
Preventing traumatic brain injury: an innovative approach to outcomes 1-day educational injury prevention programme for young people with speeding offences Farmer J, et al: Brain Injury 14:109-15, 2000
Rate of convictions after the target programme date • 92 programme participants and 87 non-treated individuals • no significant between-group difference Farmer J, et al: Brain Injury 14:109-15, 2000
MOST program McSwainN, et al: J Trauma 30,10:1189-1199, 1990
Epidemiology and prevention of traffic injuries to urban children and adolescents. Durkin MS, et al: Pediatrics 103: 66-74, 1999
Costly achievements • Education in a simulated traffic environment, and via theatrical performances • Construction of new playgrounds to provide expanded off-street play areas for children • Bicycle safety clinics and helmet distribution • Supervised recreational and artistic activities Durkin MS, et al: Pediatrics 103: 66-74, 1999
Traffic related mortality and the reunification of Germany FK Winston, et al: BMJ318: 1647-1650, 1999
Renewed emphasis on law enforcement • Seat belts • Helmet • Speed regulation • Poison control Passive protection works Satcher D: JAMA 284:950, 2000
100 90 80 70 % Helmet use 60 50 40 30 20 10 0 Law Repeal 78 79 80 Voluntary helmet use does not work
100 90 80 70 % SB use 60 50 40 30 20 10 0 Months 0 1 8 12 Rate of seat belts use after law implementation
50 40 % reduction 30 20 10 0 Seat Belt AirBag Combined Jagger J et al.: Neurosurgery 20:815-817,1987 Expected reduction of severe head injury
2. Violence Violence is a leading cause of TBI--especially among males--and violence with firearms is the leading cause of TBI-associated death. Effective programs designed to decrease the occurrence of interpersonal and self-directed violence would help address this cause.
3. Falls Falls are the third leading cause of TBI-associated death. Among women over 75 years of age and men over 85 years of age, falls are the leading cause of TBI-associated death. Falls are also a major cause of nonfatal TBI. Effective interventions may involve modifying the environment to reduce fall hazards and the impacts of falls and, where possible, reducing the use of medications with side effects that increase the risk of falling.
Outcome trendData from literature 60 Unfavourable outcome 40 Favourable outcome 20 Jennet TCDB Fearnside EBIC Maas AIR: Neurosurgery 44:1286-1298; 1999
0,45 0,40 Good O. 0,35 Mod. dis 0,30 0,25 Sev. dis 0,20 Veg 0,15 Dead 0,10 0,05 0,00 1 2 3 4 5 GOS 6 months NL MI 97+98
0,45 0,40 0,35 Good O. 0,30 Mod. dis 0,25 Sev. dis 0,20 Veg 0,15 Dead 0,10 0,05 0,00 1 2 3 4 5 GOS 6 months Pat. in coma NL MI 97+98
0,40 0,35 Good O. 0,30 Mod. dis 0,25 Sev. dis 0,20 Veg 0,15 Dead 0,10 0,05 0,00 1 2 3 4 5 GOS 6 months in coma, at least 1 reactive pupil NL MI 97+98
Stroke killed 158,448 people in 1998 and accounted for about 1 of every 14.8 deaths in the United States (is the most common life-threatening neurological disease). • About 47 percent of these deaths occur out of hospital. Total mention mortality about 280,000. • The morbidity of stroke, i.e., incidence and prevalence, is shared about equally between men and women. At all ages, more women than men die of stroke.
Estimated prevalence of stroke by age and sexUnited States: 1988–94 % population
When considered separately from other cardiovascular diseases, stroke ranks as the third leading cause of death, behind diseases of the heart and cancer. (CDC/NCHS) On average, someone in the United States suffers a stroke every 53 seconds; every 3.3 minutes someone dies of one. Each year, about 600,000 people suffer a new or recurrent stroke. About 500,000 of these are first attacks, and 100,000 are recurrent attacks. (Framingham Heart Study, NHLBI)
The most common variety of complete strokes is atherothrombotic brain infarction, which accounts for 61 percent of all strokes (excluding TIAs). The next most common is cerebral embolus (24 percent). (44-year follow-up of participants and 20-year follow-up of their offspring, Framingham Heart Study, NHLBI)
Of incident definite or probable strokes reported in the the NHLBI’s ARIC study, 83 percent were ischemic, 10 per-cent were intracerebral hemorrhage, and 7 percent were subarachnoid hemorrhage. Among the 178 definite thrombotic brain infarctions, 38 percent were classified as lacunar strokes (in small blood vessels) and twice as many were in blacks as in whites. (Stroke, 1999;30:736–743)
7.6 percent of ischemic strokes and 37.5 percent of hemorrhagic strokes result in death within 30 days. (Stroke, 1999;30:736–743) About 4,500,000 stroke survivors (2,200,000 males and 2,300,000 females) are alive today. From 1988 to 1998, the stroke death rate fell 15.1 (15.5) percent, but the actual number of stroke deaths rose 5.3 percent.