a b s t r a c t

Objective: To investigate the characteristics of stair-related injuries among individuals of all ages and estimate na- tional injury frequencies and rates using a representative sample of patients treated in United States emergency departments.

Methods: Data from the National Electronic Injury surveillance System were analyzed for patients treated for stair-related injuries in United States emergency departments from 1990 through 2012.

Results: An estimated 24,760,843 patients were treated in emergency departments for a stair-related injury dur- ing the 23-year study period, averaging 1,076,558 patients annually, or 37.8 injuries per 10,000 United States res- idents. The annual rate of stair-related injuries decreased by 12.6% (p b 0.001) during 1990-1996, followed by an increase of 24.0% (p b 0.001) during 1996-2012. Although the highest injury rates occurred among younger chil- dren and older adults, the majority (67.2%) of emergency department visits for stair-related injuries was by in- dividuals 11-60 years old. Most patients were female (62.4%), who also had a higher injury rate (46.5 vs. 29.1 per 10,000) than males. Sprains and strains (32.3%), soft tissue injuries (23.8%), and fractures (19.3%) were the most common types of injury. The body regions most frequently injured were the lower extremities (42.1%) and head/neck (21.6%). Patients <=10 years old experienced more head/neck injuries. Older adult patients more frequently sustained fractures than younger age groups.

Conclusions: Stairs are a common source of injury among individuals of all ages and the frequency and rate of stair-related injuries are increasing. This underscores the need for increased Prevention efforts, particularly those related to stair design and construction.

(C) 2017

Introduction

Stairs are present inside an estimated 49% of homes in the United States (US), not including single-story dwellings that may require stairs for access [1]. Although frequent exposure to these structures may lead many people to underestimate their potential to be associated with in- jury, such injuries are well-documented in the research literature [2-14]. Most stair-related injuries do not result in serious medical out- comes [2-6,11]; however, it is important to note that fatalities do

Abbreviations: CHI, closed head injury; CI, Confidence interval; CPSC, United States Consumer Product Safety Commission; ED, Emergency department; NEISS, National Electronic Injury Surveillance System; RR, Relative risk; US, United States.

* Corresponding author at: Center for Injury Research and Policy, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus, OH 43205, United States.

E-mail address: [email protected] (G.A. Smith).

¹ Address where work was done: Center for Injury Research and Policy, The Research Institute at Nationwide Children’s Hospital; 700 Children’s Drive; Columbus, OH 43205.

occur [2,8,10,15,16]. Overall, falls are the leading cause of non-fatal inju- ry in the US, and are associated with significant morbidity and mortality among older adults [16,17]. Because stairs are so prevalent in society and are a common location for falls to occur, it is important to study stair-related injuries across all age groups.

Previous studies have documented the frequency and characteristics of stair-related injuries among children [3-6,11-13,18]. There is also existing research describing high rates of stair-related injuries among older adults, as well as the associated morbidity and mortality [2,8,10, 14,19,20]. Numerous studies have examined gait characteristics of dif- ferent age groups and their relationship to relative injury rates [21-31]. In addition to describing injuries, studies have also investigated the costs associated with stair-related injuries [32-35]. It is estimated that non-fatal injury-related direct medical and indirect costs are $92 billion annually in the US [35].

The objective of the current study is to investigate the epidemiolog- ical characteristics of stair-related injuries among all ages using a na- tionally representative sample over a multi-year period. Our study

https://doi.org/10.1016/j.ajem.2017.09.034

0735-6757/(C) 2017

injury characteristics and “>also expands upon prior research on this topic to investigate the mech- anisms of stair-related injuries and examine trends.

Methods

Data source

Data for patients treated in US emergency departments (EDs) for stair-related injuries from January 1, 1990 through December 31, 2012 were obtained through the National Electronic Injury Surveillance Sys- tem (NEISS). The NEISS, developed in 1972 and maintained by the US Consumer Product Safety Commission (CPSC), provides consumer prod- uct-related and sports and recreational activity-related injury data from a stratified probability sample of approximately 100 US hospital EDs that provide 24-h care and have at least six beds [36]. Professional NEISS coders review ED medical charts at each participating hospital and transcribe data into the NEISS database. Data are weighted to pro- vide national estimates of injury.

Case selection criteria

All NEISS cases from 1990 through 2012 that involved stairs or steps (NEISS product code 1842, which excludes pull-down and folding stairs) were obtained. Fatalities were excluded (n = 192), because the NEISS does not capture fatal cases well. Cases involving escalators, lad- ders, or step stools (NEISS codes 0618, 0619, 0620, 0688, 1890, 3262,

4032, 4033, 4077, and 4078) were not included in this study. After ap- plying case selection criteria, there were 650,255 unweighted stair-re- lated injuries included in this study.

Variables

NEISS variables included in study analyses were patient age and gen- der, body region injured, injury diagnosis, disposition from the ED, lo- cale of injury, as well as the brief case narrative describing the incident. Cases were categorized into nine single-decade age groups for investigation of age-related trends. In order to examine injury fre- quencies and rates among younger children and older adults separately, we divided cases into three broader age categories: (1) younger chil- dren (<= 10 years), (2) older children and adults (11-60 years), and (3) older adults (>= 61 years). Body region injured was collapsed into 5 body regions: (1) head/neck, (2) upper extremity (including shoulder),

(3) trunk, (4) lower extremity, and (5) other/not specified. Diagnosis was categorized as: (1) strains/sprains, (2) soft tissue injury (including contusions, abrasions, and hematomas), (3) fractures, (4) lacerations (including lacerations, amputations, and punctures), (5) concussion/ closed head injury (CHI; i.e., internal organ injury to the head region), and (6) other/not specified. Disposition from the ED was regrouped into four categories: (1) examined/treated and released from the ED,

(2) hospitalized (including treated and admitted, transferred for hospi- talization or to another hospital, and held for observation), (3) left against medical advice, and (4) not specified. The location of injury was recoded as (1) home (including home, apartment, condo, and mo- bile home), (2) outside of the home (including school, farm/ranch, street/highway, industrial place, other public property, sports or recrea- tion place), or (3) not specified.

Assisted by a computerized keyword search, information included in

the case narratives was used to categorize mechanism of injury into the following groups: (1) fell on stairs via unspecified mechanism (includ- ing tumbles); (2) slid or slipped on stairs; (3) tripped on the stairs or over an object on the stairs; (4) missed a step or had a misstep (includ- ing stumbles); (5) running or playing (including intentional risky be- haviors, such as riding down the stairs on a toy or sliding down the banister); (6) fell while carrying an object, child, or person, or while being carried; and (7) other. For case narratives describing multiple mechanisms of injury, the first mechanism in a temporal sequence of

mechanisms was chosen. For example, if a person was carrying a basket of clothes down the stairs and then tripped, the case was coded as car- rying an object.

Statistical analysis and ethical statement

Data were analyzed using IBM SPSS 24.0 (Armonk, NY) statistical software. Statistical analyses included piecewise linear regression to evaluate the statistical significance of secular trends, chi-square analy- sis, and Relative risk with a 95% confidence interval (CI). The esti- mated slope from the regression model (m) was reported with the associated p-value. The level of significance was set at ? <= 0.05 for all statistical tests. Injury rates per 10,000 US residents were calculated using data from the US Census Bureau [37-39]. US census data combine all individuals 85 years of age and older into one age group; therefore, injury rates in this study were calculated accordingly. National esti- mates were calculated using NEISS weights provided by the CPSC, and all numbers reported in this study are national estimates unless other- wise identified as unweighted cases. The institutional review board at the authors’ institution determined that this study was exempt.

Theory

This study provides a comprehensive epidemiological analysis of na- tionally representative emergency department data covering a 23-year period regarding an important source of injury morbidity in the US. In addition, within the context of study findings, this article describes rel- evant injury Prevention strategies.

Results

Overall injury characteristics and trends

An estimated 24,760,843 (95% CI: 20,833,284-28,688,402) individ-

uals were treated in US EDs for stair-related injuries from 1990 through 2012, averaging 1,076,558 stair-related injuries per year or an annual rate of 37.8 per 10,000 US residents (Table 1, Fig. 1). The number of in- juries decreased (-5.8%, m = -8391.1, p = 0.065) from 951,550 cases in 1990 to 896,769 cases in 1996, before increasing to 1,296,148 cases in 2012 (44.5%, m = 24,925.0, p b 0.001; Fig. 1). This corresponded to a 12.6% (m = -0.765, p b 0.001) decrease in the rate of stair-related in- juries from 1990 (38.1 per 10,000 population) to 1996 (33.3 per 10,000 population), followed by a 24.0% (m = 0.494, p b 0.001) increase from 1996 to 2012 (41.3 per 10,000 population).

Patients ranged in age from b 1 to 115 years old, with a mean age of

36.7 years (standard error of the mean: 0.53; median: 33.6, interquartile range: 18.4-52.0). Female patients accounted for 62.4% of all stair-relat- ed injuries, and the majority of injuries (61.2%) occurred at home (Table 1). The body regions most commonly injured were the lower extremi- ties (42.1%), head/neck (21.6%), and trunk (18.1%), and the most com- mon diagnoses were strain/sprain (32.3%), soft tissue injury (23.8%), and fracture (19.3%) (Table 1). Lower extremity injuries were most commonly strains/strains (54.1%) and fractures (21.4%), upper extrem- ity injuries were primarily fractures (37.0%) and soft tissue injuries (26.1%), and most trunk injuries were soft tissue injuries (38.9%) and strain/sprains (27.0%). Among head/neck injuries, 34.1% were lacera- tions, 26.6% were concussions/CHIs, and 25.6% were soft tissue injuries. The majority (93.8%) of patients were examined/treated and re- leased from the ED and 5.7% of injuries resulted in hospitalization (Table 1). The rate of hospitalization per 10,000 population decreased by 26.7% (m = 0.11, p b 0.001) from 2.1 in 1990 to 1.6 in 1997, and

then increased by 99.8% (m = 0.10, p b 0.001) from 1997 to 3.1 in 2012. More than one-half of the injuries requiring hospitalization were fractures (59.4%), and an additional 14.2% were concussions/ CHIs. Overall, 59.4% of injured patients fell down the stairs without a

Table 1

Characteristics of stair-related injuries treated in emergency departments in the United States, NEISS 1990-2012.

	<= 10 Years	11-60 Years	>= 61 Years	Total
Characteristics	n (%)a	n (%)a	n (%)a	n (%)a	95% CI
Gender
Male	2,045,122 (55.8)	5,944,214 (35.7)	1,307,205 (29.4)	9,298,421 (37.6)	7,830,577-10,766,264
Female	1,621,697 (44.2)	10,699,857 (64.3)	3,135,207 (70.6)	15,458,185 (62.4)	12,980,928-17,935,441
Not specified	963 (0.0)d	2379 (0.0)d	825 (0.0)d	4237 (0.0)	2782-5693
Location
Home	2,314,410 (63.1)	10,030,244 (60.3)	2,802,228 (63.1)	15,148,717 (61.2)	12,488,781-17,808,653
Outside of home	265,650 (7.2)	1,207,170 (7.3)	476,503 (10.7)	1,949,646 (7.9)	1,582,908-2,316,383
Not specified	1,087,722 (29.7)	5,409,036 (32.5)	1,164,507 (26.2)	7,662,480 (30.9)	5,785,344-9,539,616
Body region injured
Head/neck	2,378,853 (64.9)	1,923,723 (11.6)	1,048,670 (23.6)	5,352,583 (21.6)	4,514,492-6,190,675
Upper extremity	485,067 (13.2)	2,721,635 (16.3)	973,262 (21.9)	4,180,472 (16.9)	3,511,195-4,849,750
Trunk	153,498 (4.2)	3,346,060 (20.1)	985,320 (22.2)	4,485,325 (18.1)	3,693,102-5,277,547
Lower extremity	591,894 (16.1)	8,479,979 (50.9)	1,360,134 (30.6)	10,432,942 (42.1)	8,781,979-12,083,904
Other/not specified	58,470 (1.6)	175,053 (1.1)	75,852 (1.7)	309,521 (1.3)	247,989-371,052
Diagnosis Strain/sprain	315,543 (8.6)	6,954,985 (41.8)	725,972 (16.3)	7,997,359 (32.3)	6,739,142-9,255,575
Soft tissue injury	1,103,732 (30.1)	3,804,547 (22.9)	989,986 (22.3)	5,899,004 (23.8)	4,965,183-6,832,826
Fracture	418,362 (11.4)	2,823,023 (17.0)	1,541,789 (34.7)	4,783,595 (19.3)	4,003,639-5,563,551
Laceration	980,330 (26.7)	916,706 (5.5)	502,784 (11.3)	2,400,287 (9.7)	2,059,532-2,741,043
Concussion/closed head injury	586,751 (16.0)	520,643 (3.1)	317,745 (7.2)	1,425,544 (5.8)	1,127,873-1,723,214
Other/not specified	263,065 (7.2)	1,626,546 (9.8)	364,962 (8.2)	2,255,054 (9.1)	1,652,073-2,858,034
Disposition from ED Examined/treated and released	3,554,321 (96.9)	16,040,455 (96.4)	3,623,307 (81.5)	23,220,642 (93.8)	19,507,360-26,933,924
Hospitalized	93,137 (2.5)	504,996 (3.0)	809,587 (18.2)	1,408,425 (5.7)	1,172,420-1,644,430
Left against medical advice	17,517 (0.5)	91,705 (0.6)	8711 (0.2)	118,026 (0.5)	81,015-155,036
Not specified	2806 (0.1)	9295 (0.1)	1632 (0.0)d	13,750 (0.1)	7688-19,811
Mechanism of injury Fell on stairs	2,488,611 (67.9)	9,577,715 (57.5)	2,635,352 (59.3)	14,704,073 (59.4)	12,359,884-17,048,262
Slid/slipped	164,802 (4.5)	1,888,179 (11.3)	414,198 (9.3)	2,467,354 (10.0)	1,981,025-2,953,683
Tripped on stairs/over object	213,910 (5.8)	1,341,719 (8.1)	535,431 (12.1)	2,091,351 (8.4)	1,705,564-2,477,137
Missed step/misstep	27,913 (0.8)	768,906 (4.6)	402,227 (9.1)	1,199,258 (4.8)	979,486-1,419,030
Running/playing	381,364 (10.4)	278,523 (1.7)	12,809 (0.3)	672,702 (2.7)	568,211-777,194
Carrying object/child/person	69,730 (1.9)	336,315 (2.0)	58,425 (1.3)	464,584 (1.9)	372,269-556,899
Other	321,452 (8.8)	2,455,092 (14.7)	384,795 (8.7)	3,161,520 (12.8)	2,658,643-3,664,397
Study total (row %)b,c	3,667,782 (14.8)	16,646,451 (67.2)	4,443,238 (17.9)	24,760,843 (100.0)	20,833,284-28,688,402

^a Column percentages may not sum to 100.0% due to rounding error.

^b Row percentages may not sum to 100.0% due to rounding error.

^c Age not specified for 3372 injured patients.

^d Estimate is potentially unstable due to sample size b20 cases, estimate b1200 cases, or coefficient of variation N 30.0%.

specified mechanism of injury and a combined 23.2% slid/slipped, tripped, or misstepped (Table 1).

Injuries by patient age and gender

The stair-related injury rate was tri-modal with peaks among chil- dren <= 3 years of age, young adults in their 20's, and adults >= 85 years old with the highest rates at the extremes of the age spectrum (Fig. 2). The overall injury rate was higher for females (46.5 per 10,000 female population) than males (29.1 per 10,000 male population); this was true across all age-groups except <= 10 year-olds (Fig. 3). When examin- ing single-decade age groups, starting in the second decade the propor- tion of injuries sustained by females, compared with males, increased with age (Fig. 3).

Although more than two-thirds of injuries occurred among older children and adults 11-60 years old (67.2%), the injury rate per 10,000 population was highest (42.2) among older adults >= 61 years old com- pared with 37.2 for older children and adults 11-60 years old and 36.8 for younger children <= 10 years old. Among younger children, the injury rate per 10,000 children <= 10 years decreased by 31.8% (m = -1.12, p b 0.001) from 45.5 in 1990 to 31.7 in 2005, followed by an 8.6% (m = 0.54, p = 0.009) increase from 2005 to 33.7 in 2012 (Fig. 4). For older chil- dren and adults, the injury rate per 10,000 individuals decreased by 15.1% (m = – 0.64, p = 0.002) from 36.0 in 1990 to 30.6 in 1996,

followed by a 36.5% (m = 0.69, p b 0.001) increase from 1996 to 41.7 in 2012. The injury rate per 10,000 older adults >= 61 years old declined by 4.6% (m = – 0.12, p = 0.641) from 39.5 in 1990 to 38.7 in 1995,

and then increased by 20.3% (m = 0.47, p b 0.001) from 1995 to 46.7

in 2012 (Fig. 4).

Males accounted for more than half (55.8%) of injuries among youn- ger children compared with 35.7% among older children and adults and 29.4% among older adults (Table 1). Patients <= 10 years old were 5.61 times (95% CI: 5.38-5.86) more likely to have injuries to the head/ neck (64.9% of all injuries) than patients 11-60 years old (11.6%) and

2.75 times (95% CI: 2.65-2.85) more likely than patients >= 61 years old (23.6%) (Table 1). Head/neck injuries among children <= 10 years old were most commonly lacerations (38.1%), soft tissue injuries (31.3%), and concussions/CHIs (24.7%).

The most commonly injured body region among older children and adults and older adults was the lower extremity (50.9% and 30.6% of in- juries, respectively). The most common diagnoses by age group were Soft tissues injury among younger children (30.1%), strains/sprains among older children and adults (41.8%), and fractures among older adults (34.7%). Patients >= 61 years old were 3.04 times (95% CI: 2.89- 3.21) more likely than patients <= 10 years old and 2.05 times (95% CI: 1.96-2.13) more likely than patients 11-60 years old to sustain a fracture.

In each age group, the majority of injures were examined/treated and released. However, patients >= 61 years old were 7.18 times (95% CI: 6.39-8.06) more likely than patients <= 10 years old and 6.01 times (95% CI: 5.56-6.49) more likely than patients 11-60 years old to be hospitalized. The most common type of injury among older adults requiring hospitalization was a fracture (65.9%). Overall, the most common mechanism of injury among all three age groups was falling

Fig. 1. Estimated number and rate of stair-related injuries by year, NEISS 1990-2012.

down the stairs without a specified mechanism (Table 1). However, the proportion of injuries related to slips/trips/missteps increased with age (younger children: 11.1%; older children and adults: 24.0%; older adults: 30.4%). Among younger children, 10.4% of injuries were related to running/playing on the stairs; of these, 50.4% were to the head/neck region.

Discussion

There were an average of 1,076,558 stair-related injuries per year during the study period, equaling an average of 2949 injuries daily, and the number and rate of injuries are increasing. The observed 24% in- crease in the rate of stair-related injuries from 1996 to 2012 was

Fig. 2. Estimated average annual number and rate of stair-related injuries by age, NEISS 1990-2012.

Fig. 3. Estimated average annual number and rate of stair-related injuries by age group and gender, NEISS 1990-2012.

primarily attributable to the 36% increase in the rate among older chil- dren and adults 11-60 years of age during 1996 to 2012 and the 20% in- crease among older adults >= 61 years of age during 1995 to 2012. The 32% decline in the rate of stair-related injuries among younger children observed from 1990 to 2005 was likely influenced by a 76% decrease in the number of infant walker-related injuries from 1990 to 2001 that was associated with introduction of stationary activity centers as an al- ternative to mobile infant walkers in 1994 and strengthening of the ASTM International F977 infant walker voluntary safety standard in 1997 [40]. Consistent with prior studies, most injuries among children were lacerations or soft tissue injuries, most frequently to the head or neck, and rarely required hospitalization [2-6,11,12]. Among older adults, injuries tended to be more severe, often included fractures, and had higher rates of hospital admission [2,8,19,20].

Although the injury rate was highest among older adults in this study, individuals 11-60 years of age accounted for more than two-

thirds of all stair-related injuries and had the second highest injury rate. Prior studies have identified the high injury rates at either end of the life spectrum, but have not emphasized this middle age group. The middle group in the tri-modal age distribution in Fig. 2 has been largely ignored. Because women account for the majority of stair-related inju- ries, including in this middle age group, a new target population for pre- vention should be women, starting in their 20’s. This study was unable to identify the reasons for the higher injury rates among these women due to the limited information contained in the NEISS case narratives. However, these are the child-bearing and parenting years and N 60% of injuries occurred in the home; therefore, a possible contributing factor could include increased exposure to stairs related to greater time in the home while caring for children and performing household chores. Prior research also has documented high rates of falls among women during pregnancy [41]. In addition, women’s footwear is different from that of men and may be a factor while navigating stairs.

Fig. 4. Estimated annual rate of stair-related injuries by age group, NEISS 1990-2012.

Given that the number and rate of stair-related injuries is increasing in the US since 1996, especially among older children and adults 11- 60 years of age and older adults >= 61 years of age, additional safeguards and prevention efforts should be employed. In construction and remod- eling of all stairways, careful consideration should be given to utilizing safe and user-friendly stair geometries. For example, increasing the length of the “goings,” or the horizontal surfaces on which your foot rests between the lead edges of each stair, and ensuring that all goings and rises (the vertical distances between two treads or a tread and a landing) are uniform [42,43]. Uniformity among all steps can help pre- vent missteps that result from a step not being where the user antici- pates it will be [42]. A missing nosing from the top step is a common first step defect. Stair patterns and geometries should be maintained all the way down to the last step, so as to avoid a bottom-of-stair illusion that may cause an individual to miss the last step [44]. In addition, installing handrails that allow for a power-grip, in which the entire hand can surround the rail, rather than just a pinch grip, can help to en- hance user stability and prevent falls [45-47]. Stairs and railings should be well-maintained and free of excess polishes that could make surfaces slippery [42]. Loose carpeting on stairs should be repaired. Given that stair design and construction are likely to have the biggest influence on preventing stair injuries [42], policy makers should consider revising building codes to require that stairs comply with best practice safety recommendations.

Aside from structural improvements, behavioral changes can also be implemented to reduce the risk of stair-related injuries. Stairs and sur- rounding areas should be well-lit and kept clear of any objects that could present a slip or trip hazard. Individuals should limit multi- tasking while navigating the stairs and use caution when carrying chil- dren or large, heavy, or bulky items, or items that may obscure one’s vi- sion, such as laundry baskets [13]. Pets may also pose a trip hazard. Individuals should maintain contact with the stair railing at all times, so that if one begins to fall, stability can be regained more easily. Chil- dren should be discouraged from running, jumping, or playing on stairs [11]. Individuals may also wish to consider the footwear they wear while walking on stairs.

Study limitations

This study has several limitations. Because this study only included patients treated in hospital EDs, it underestimates the total number of stair-related injuries in the US. Injuries that are treated in other healthcare settings, or that are untreated, are not captured in the NEISS. In addition, the NEISS underestimates fatalities because it does not capture fatalities that are not transported to the ED or deaths that occur after patients are admitted to the hospital, and for that reason, fa- talities were excluded from this study. NEISS case narratives are manu- ally transcribed by individual coders, and thus, may be inconsistent or lack complete details about the circumstances surrounding the injury. Additionally, there may be incomplete documentation in the ED medi- cal record by medical personnel, resulting in missing information. De- spite these limitations, a strength of this study is that a large, nationally-representative sample was used to characterize stair-related injuries among patients of all ages over a 23-year study period.

Conclusions

This study demonstrates that stair-related injuries are an important common cause of injury among individuals of all ages. The number and rate of stair-related injuries treated in US EDs are increasing, indicating a need for more effective prevention efforts. Notably, a large proportion of the injury burden occurs to the adult female population. Although the causes for this finding are uncertain, it is an important factor to consider when developing targeted interventions for this injury problem. Pre- vention strategies include revising building codes and updating existing stairways to comply with geometric dimensions recommended for

optimal safety, ensuring uniformity of all stairs in a stairway, and instal- lation of stair rails that allow for use of a power grip. Individuals can help prevent injuries by keeping stairways clear of clutter and trip hazards, ensuring that stairways are well-lit, and reducing multi-tasking while navigating the stairs.

Funding source

Author Danielle Herbert Blazewick received a research scholarship stipend from the National Student Injury Research Training Program at Nationwide Children’s Hospital, funded by the National Center for In- jury Prevention and Control, Centers for Disease Control and Prevention (grant #1R49CE002106) and Child Injury Prevention Alliance, while she worked on this study. The interpretations and conclusions in this article do not necessarily represent those of the funding organizations.

Financial disclosure statement

The authors have nothing to disclose relevant to this study.

Conflict of interest statement

The authors have no conflicts of interest relevant to this study.

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