Nonfatal Self-Inflicted Injuries Among Adults Aged >65 Years --- United States, 2005

In 2005, an estimated 372,722 persons in the United States were treated in hospital emergency departments (EDs) for intentional, nonfatal self-inflicted injuries (1). Nonfatal self-inflicted injuries are most common among adolescents and young adults (2); few studies have investigated these types of injuries among adults aged >65 years. However, older adults are one of the fastest-growing population groups in the United States and can require more extensive and more costly medical treatment than younger adults. To characterize ED visits for nonfatal self-inflicted injuries among U.S. adults aged >65 years, CDC analyzed ED visits for 2005 using data from the National Electronic Injury Surveillance System All Injury Program (NEISS-AIP). This report summarizes the results of that analysis, which indicated that, in 2005, adults aged >65 years made an estimated 7,105 visits to EDs (i.e., 19.3 visits per 100,000 population) for nonfatal self-inflicted injuries, and ED health-care providers attributed 80.4% of these visits to suicidal behavior. In addition, a significantly higher percentage of adults aged >65 years compared with younger adults were hospitalized after ED visits for suicidal behavior. Comprehensive prevention strategies that combine community outreach, crisis intervention, and clinical management are needed to decrease morbidity and mortality from suicidal behavior among older adults.

NEISS is operated by the U.S. Consumer Product Safety Commission and collects data about treatment of patients in U.S. hospital EDs for consumer-product--related injuries.* The expanded system, NEISS-AIP, collects data about treatment of patients for all types and causes of injuries in U.S. hospital EDs, regardless of whether the injuries are related to consumer products. NEISS-AIP includes data from 66 of the 100 NEISS hospitals that were selected as a stratified probability sample of all hospitals in the United States and its territories with a minimum of six beds and a 24-hour ED (3,4). Data are weighted by the inverse of the probability of selection to produce national estimates (3). NEISS-AIP provides data on approximately 500,000 injury-related ED cases each year (3). Estimates for this report were based on weighted data for 4,478 nonfatal self-inflicted injuries for which persons aged >20 years were treated in EDs during 2005. The weighted values were used to provide annual estimates for adults aged 20--34 years, 35--49 years, 50--64 years, and >65 years.

NEISS-AIP defines injuries as bodily harm that results from acute exposure to an external force or substance and includes unintentional or violence-related causes (2). Cases are excluded if the ED visit is for unintended adverse effects of therapeutic drugs or surgical and medical care or the principal diagnosis is unknown or is an illness, pain only, psychological harm only (e.g., anxiety and depression), or contact dermatitis associated with exposure to plants or consumer products (2,5). Injuries are classified into mutually exclusive categories according to intent of injury (i.e., unintentional, assault, self-inflicted, and legal intervention^†) (2). Data on sex, race/ethnicity, ED discharge disposition (i.e., treated then released, transferred then released, hospitalized, or left against medical advice or before being treated), and mechanism of injury (e.g., by cutting or piercing, poisoning, or a firearm gunshot) also are collected; mechanisms of injury are classified into major external cause-of-injury groups (5,6) using definitions consistent with International Classification of Diseases, Ninth Revision, Clinical Modifications guidelines (7).

To categorize self-inflicted injuries by intent of injury, CDC analyzed screening forms that were completed by trained NEISS hospital coders using ED patient charts. The forms included information about 1) the ED clinician's description or diagnosis of the injury event, such as whether the visit resulted from suicidal behavior (i.e., intent to die was demonstrated or expressed by the patient) or self-abusive behavior (i.e., self-injurious behavior, such as self-mutilation, without the intent to die); 2) existing medical and psychiatric conditions of the patient (e.g., clinical depression, alcohol abuse, or substance abuse) as reported by patients or their relatives or friends; and 3) alcohol or recreational drug use at the time of the injury as determined by hospital staff members or laboratory reports.

During 2005, an estimated 7,105 ED visits for nonfatal self-inflicted injuries occurred among older adults (i.e., persons aged >65 years) (rate: 19.3 per 100,000 population), and 80.4% of these visits resulted from suicidal behavior (Table 1). Rates did not differ significantly between older adult men and women. Older adults had too few visits for self-abusive behavior to estimate a national rate. For all adult age groups, the majority of the ED visits for nonfatal self-inflicted injuries occurred among non-Hispanic whites.

Among ED visits attributed to suicidal behavior, a significantly higher percentage of older adults (70.6%) were hospitalized after ED care than adults aged 20--34 years (42.8%) (Table 2). The most common mechanism of injury related to suicidal behavior among all age groups was poisoning. Alcohol use at the time of the injury was less common among adults aged >65 years (15.1%) than among adults aged 20--34 years (28.6%) and 25--49 years (34.9%). As with the younger age groups, the majority of older adults (73.7%) who visited an ED for suicide-behavior--related injury had a history of depression.

Reported by: A Crosby, MD, Div of Violence Prevention, G Ryan, PhD, Office of Statistics and Programming, National Center for Injury Prevention and Control, J Logan, PhD, EIS Officer, CDC.

Editorial Note:

The findings in this report indicate that, in 2005, ED visits for nonfatal self-inflicted injuries were less common among adults aged >65 years than among younger adults. However, older adults were more likely than younger adults to be hospitalized after ED treatment for an injury related to suicidal behavior. In addition, for older adults whose visits were related to suicidal behavior, alcohol use at the time of the injury was less frequently reported.

Despite the finding that the rate of ED visits for nonfatal injuries from suicidal behavior is lower among older adults, the suicide rate is higher among older adults (8), particularly among those aged >75 years (1); in 2004, 16.4 suicides occurred per 100,000 population among those aged >75 years, compared with 12.6 among persons aged 20--34 years (1). In addition, the ratio of nonfatal suicidal incidents to suicides is substantially lower among older adults than younger adults (8), which might partly explain the relatively low rate of nonfatal incidents among older adults in this analysis. One study determined that the ratio of suicide attempts to completed suicides decreases with age, from as high as 200:1 among persons aged 15--24 years to 4:1 among adults aged >65 years.^§ The most common mechanism for suicide among older adults is use of a firearm (8), a mechanism that is more likely to be fatal than poisoning, the most common cause for ED visits among all age groups for nonfatal suicidal behavior.

The findings in this report are subject to at least five limitations. First, small numbers of ED visits among particular subgroups of adults made certain rate estimates unstable. Second, classification of injuries caused by suicidal behavior was based on information solicited and recorded by ED health-care providers. Certain self-inflicted injuries that ED clinicians did not identify as related to suicidal behavior might later have been classified as such by clinicians who provided follow-up treatment, possibly resulting in an underestimation of those injuries. Third, although the screening tool was used to collect information regarding patient history of mental and behavioral conditions, information on mental distress, behavioral problems, or dementia at the time of the injury was not collected, thereby limiting the ability to understand certain circumstances preceding these events. Fourth, certain self-inflicted injuries from poisoning might have been misclassified as unintended adverse drug events and excluded from this study; therefore, self-inflicted injuries attributable to poisoning might be underestimated. Finally, because not all self-inflicted injuries result in ED visits, these findings likely underestimate the actual rates of self-inflicted injuries.

Because the older adult population is the fastest-growing age group of the U.S. population, the number of self-inflicted injuries in this group is likely to increase. These incidents can lead to more serious medical complications and hospitalizations than similar behaviors among younger adults because older adults are more likely to have comorbid conditions and longer recoveries. One study indicated that the average cost among older adults is approximately twice the average medical cost per case among adults aged 25--64 years ($9,749 versus $4,995) (9).

The findings in this report illustrate the need for primary prevention measures that focus on the older adult population. Although few evaluated prevention programs have focused on older adults, promising strategies exist, such as better identification and treatment of clinical depression by primary-care physicians and increased social support for persons at risk (8). For example, one study documented that training primary-care staff members to identify and treat adults for clinical depression was associated with lower suicide rates (8). Additional research is needed to assess a broader scope of potential risk factors for suicidal behavior among older adults and to develop strategies for decreasing these risk factors.

References

1. CDC. Web-based injury statistics query and reporting system (WISQARS^™). Available at http://www.cdc.gov/ncipc/wisqars.
2. CDC. Nonfatal self-inflicted injuries treated in hospital emergency departments---United States, 2000. MMWR 2002;51:436--8.
3. Kessler E, Schroeder T, eds. The NEISS sample: design and implementation. Washington, DC: US Consumer Product Safety Commission; 2000.
4. US Consumer Product Safety Commission. The NEISS coding manual 2000. Washington, DC: US Consumer Product Safety Commission; 2000.
5. CDC. Recommended framework for presenting injury mortality data. MMWR 1997;46(No. RR-14).
6. CDC. A training module for coding mechanism and intent of injury for the NEISS All Injury Program. Atlanta, GA: US Department of Health and Human Services, CDC; 2000.
7. US Department of Health and Human Services. Generic ICD-9-CM. Hospital version 1999. Reno, NV: Channel Publishing LTD; 1998.
8. Conwell Y. Suicide in later life: a review and recommendations for prevention. Suicide Life Threat Behav 2001;31(Suppl):32--47.
9. Corso PS, Mercy JA, Simon TR, Finkelstein EA, Miller TR. Medical costs and productivity losses due to interpersonal and self-directed violence in the United States. Am J Prev Med. In press 2007.

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Date last reviewed: 9/26/2007