Epidemiological, Demographic and Outcome Characteristics of Burns

Introduction

In 2014, approximately 200,000 deaths occurred in the United States from all injuries, and 31 million sustained nonfatal injuries. In a population of 318,857,056 persons, this represents a per capita death rate from injury of 0.063% (or approximately 6 per 10,000), and a nonfatal injury rate of 9.73% (or approximately 1 in 10). Therefore injury is common but related death is uncommon. For injuries from fire and burns specifically, 3,194 deaths occurred (1/100,000 population), which represented 1.6% of all injury fatalities but only 1.3% of injuries. In all, 408,945 nonfatal burns occurred in the United States in 2014, giving a rate of 0.129% of persons in the United States sustaining a burn, or about 1 per 1000.

We constructed trend lines in addition to the preceding data in the rate of reported injuries and death since 2005. These data were found on the WISQAR database produced by the U.S. Centers for Disease Control and Prevention (CDC). We found that total injuries were relatively unchanged in this period from 2005 to 2009, then saw a large spike (a 10% increase) from 2010 to 2012. This spike has since receded ( Fig. 3.1 ). When seen on a per capita basis, a 7.5% increase in the rate of reported injury occurred in the 2010–2012 period; therefore the spike in reported injuries was not from an increase in population; this is an interesting societal trend. Of further interest is the increase in injury fatalities which began at the same time and is mostly associated with an increased injury mortality rate (a 12.3% increase from 0.57% to 0.64%). This continues to rise despite a subsequent decline in total and per capita injuries. Whether this is from an increase in injury severity or age distribution cannot be answered in these data. A potential reason is a perceived increase in the use of palliative withdrawal of care, suggesting that those who might live with known treatments are unnecessarily adding to the mortality rate.

The incidence of total burns saw a similar spike in the 2010–2012 period, but this was not reflected in the per capita statistics, likely because of blunting by the relatively low incidence of burns ( Fig. 3.2 ). Interestingly burn fatalities continue to decrease overall with a flattening trajectory in 2013–2014. The per capita numbers also showed a decline that has leveled at 0.001% (1 in 100,000). What is not seen is an increase in burn fatality rate that is evident in the all-injury fatality rate.

Burns occur unequally among the age groups in the WISQAR data, and the interim changes from 2005 to 2014 are interesting. The total number of burns have generally decreased in those aged 0–45, whereas the total number of burns in those older than 45 have increased dramatically, 31% from 2005 to 2014 in those aged 46–65, and 12% in those aged over 65 ( Table 3.1 ).

The spike seen in total injuries between 2010 and 2012 is parallel with burns in those aged 0–4 but has settled back to a 6% decline in this age group from that in 2005. For those aged 5–18, we see a similar steady decline in the number of burns, and also in those aged 19–45. However the numbers of burns in those aged 46–65 and in those older than 65 years have seen a steady and dramatic increase. When indexed to population, this is almost completely accounted for by the increase in population in these age groups. Therefore no increase in per capita rate has occurred, and the increased numbers are from an increase in the population of those aged over 45 years.

When considering plans in health care utilization to respond to changes in the incidence of burns, strategies should be for the total number of burns likely to be encountered. For regional plans, per capita estimations should be used as specific regions grow and contract. In this light, the past 10 years have seen a significant decrease in the total number of burns in those aged 45 years and younger. Populations in the United States are generally stable for these age groups in the past 10 years, thus the decline in total numbers of burns must be attributed to cultural changes and prevention efforts, both legislative and educational. Therefore future resource utilization for the care of burns in this age group in the United States will likely continue to diminish unless some change occurs in the population. However those older than 45 years continue to increase in many areas, and thus considerations might be made to plan for further growth in burns in older persons.

We then analyzed the epidemiologic data from the National Burn Repository (NBR) available from the American Burn Association for the years 2006–2015. In this, we examined recent trends in burn incidence and qualities in the United States. The NBR contains data from 96 of the128 self-designated burn centers in the United States as well as 7 burn centers in Canada, Sweden, and Switzerland. Of these 96 centers, 65 were verified as a burn center using American Burn Association criteria. The data we include here come only from the reporting US centers.

The distribution of burns among age groups in the NBR data has more granularity than does the WISQAR data. Burn distribution has a major grouping in those younger than 10 years of age. Those aged 11–20 have a smaller incidence, which then increases in those aged 21–60; thereafter the total numbers decline ( Fig. 3.3 ) for a bimodal distribution when grouped in this way. Among these, 67% were in men, which is similar to previous reports of burns by gender. In terms of ethnicity, 58% of burns in the United States were in European-Americans, 21% in African-Americans, 13% in Hispanic-Americans, 5% in other ethnicities, and 3% in Asian-Americans.

Most burns were below 10% total body surface (TBSA), which included 78% of the burned population. Another 14% measured 11–20% TBSA, and the remaining 8% were greater than 20% TBSA. These numbers are all from designated burn centers, and it is likely that many additional burns below 10% TBSA were treated in nonburn centers. With this in mind, it is likely that almost all burns over 10% were treated at burn centers, thus the distribution in the NBR data is likely to be biased to larger burns from the true incidence in the United States.

Most burns were the result of injuries due to fire and flame at 41% of the total. Scalds accounted for another 33%, followed by contact with hot objects at 9%, and then chemical and electrical burns at 3% each. Overall mortality for those with burns was 3.1% during this period, which declined by almost 25% from 4.0% in 2006. Mortality was generally higher in women, except in 2015. Deaths did increase significantly with burn size (as expected), which was almost linear with increasing burned area (regression formula y = x – 13.7, r ² = 0.97) ( Fig. 3.4 ). This is a change from previous mortality rates, which was mostly a first-order distribution. According to this formula, probability of mortality for a burn (without considering age) can be estimated at %TBSA burned minus 14.

We did a probit analysis on the overall mortality data which revealed an LD50 for a 55% TBSA burn among all age groups. Thus a 55% TBSA burn would be expected to have a mortality rate of 50%; this is an improvement from previous reports. When the Baux score (age plus TBSA burned) was examined for mortality, a 50% mortality was reported at about 105 and a 90% mortality was reported at 130.

Demography

Geographic and housing tract location significantly influences the rate of house fires and the subsequent death rates from associated burns. Age of the home, economic status, number of vacant houses, and immigration status affect the house fire rate. House fire death rates are higher in the Eastern part of the United States, particularly the Southeast, compared to the West. Cooking is the leading cause of house fires in the United States: 46% of house fires and 44% of fire-related injuries are by this cause. Another leading cause of house fires is from heating equipment at 16% of instances. Other causes include electrical system fires (9%), intentional fires (8%), and fires from cigarette smoking (5%). Interestingly the cause of fire with the highest mortality is that from cigarette smoking, comprising 22% of residential fire-related deaths ( Table 3.2 ). The ratio of deaths compared to other causes is also much higher in this group, at 4.4.

Gratifyingly the number of residential fires has dramatically decreased since 2004, falling 22%; similarly related fire death rates have fallen by the same amount. Injuries, however, have only gone down by 7%, suggesting that in those fires that do occur, more injuries are occurring. Interestingly fire death rates are reduced by 50% with working fire alarms. When the rate of fire deaths is considered by state, we find these are highest in Alabama, Alaska, Arkansas, District of Columbia, Mississippi, Oklahoma, Tennessee, and West Virginia. The lowest rates are Arizona, California, Colorado, Florida, Massachusetts, Nevada, New Jersey, Texas, and Utah.

The economic consequences of residential fires are also great. The highest fire-related losses in recent history were in 2008, with $16.7 billion in property damage and other direct costs. This has significantly fallen since then, with a reported $11.5 billion in losses in 2013. The healthcare costs of burns are also prodigious. Each year in the United States, 40,000–60,000 people undergo in-hospital care for burns. The average charges for hospital care of a burned patient range from $47,557.00 to $1,203,410.00 (average $92,377), with much higher costs incurred by patients with extensive burns. The length of hospital stay ranges from one day to hundreds of days (mean 9.7), and, for patients 80 years and older is more than twice as long as that for children under 5.

High-Risk Populations