What Doesn't Kill You Doesn't Make you Stronger: The Long-term Consequences of Nonfatal Injury for Older Adults

Dongjuan Xu, PhD; Julia A. Rivera Drew, PhD

Disclosures

Gerontologist. 2018;58(4):759-767. 

In This Article

Abstract and Introduction

Abstract

Purposey: The majority of research efforts centering on injury among older adults focus on fall-related injuries and short-term consequences of injury. Little is known about the long-term consequences of all-cause nonfatal injuries, including minor injuries. Using a recent, large, and nationally representative sample of the U.S. non-institutionalized civilian population, the current study examines whether older adults who sustained a nonfatal injury (serious and minor) have higher risk of long-term morbidity and mortality outcomes compared with noninjured seniors.

Methods: Linked National Health Interview Survey-Medical Expenditure Panel Survey (NHIS-MEPS) data were used to fit logistic and 2-part models to estimate associations between injury incidence and later injury, hospitalization incidence, and length of hospital stay during the 2.5 years following the NHIS interview among 16,109 older adults. Data from the linked National Health Interview Survey-National Death Index (NHIS-NDI) files were used to estimate a Cox proportional hazards model to examine the association between injury incidence and mortality for up to 11 years after the initial interview among 79,504 older adults.

Results: Relative to no injury, serious nonfatal injury was significantly associated with increased risk of another injury, hospitalization, and mortality. Minor injuries were significantly related to higher risk of later injury and mortality.

Implications: Because even minor injuries are strongly associated with increased risks of later injury and mortality, preventing injury among seniors may be an effective way to improve quality of life and reduce declines in functional capacity.

Introduction

Injuries are a leading cause of death among older adults in the United States. Their magnitude is on par with deaths from Alzheimer's disease, diabetes, and influenza (Dellinger & Stevens, 2006), and fatal and nonfatal injuries incur annual costs of more than $40 billion in direct medical care (CDC, 2014b). The impact of injuries on quality of life for older adults may be even greater than what can be expressed in terms of immediate mortality and cost of injuries. Nonfatal injuries may result in a cascade of other health consequences, such as functional limitations or a fear of reinjury, that can negatively impact emotional and mental health, social role functioning, pain, and other quality of life domains, increase frailty, decrease the ability to live independently, and increase the chances of premature death (Carter & Porell, 2011; Inaba, Goecke, Sharkey, & Brenneman, 2003; Noro & Aro, 1996; Porell & Carter, 2012; Stevens, Corso, Finkelstein, & Miller, 2006; Tinetti & Williams, 1997; Vellas, Wayne, Romero, Baumgartner, & Garry, 1997; Yang, Norton, & Stearns, 2003).

All-cause nonfatal injury among older adults has not received much attention in prior research. The majority of research and prevention efforts centering on injury among older adults has focused on fall-related injuries, which constitute 60% of all nonfatal injuries among community-dwelling older adults (Xu & Drew, 2016). As a result, we know little about overall patterns in nonfatal injury consequences for older adults. Of existing research, most examined short-term consequences of all-cause injury, such as costs of health care received immediately following injury (Finkelstein, Chen, Miller, Corso, & Stevens, 2005) or 30-day in-hospital mortality following injury (Gorra, Clark, & Mullins, 2011). The few studies characterizing the long-term consequences of nonfatal injuries among older adults found that nonfatal injuries led to several long-term consequences, spanning health-related quality of life (Inaba et al., 2003), medical care spending (Carter & Porell, 2011), institutionalization (Porell & Carter, 2012), and death (Porell & Carter, 2012). Serious nonfatal injury resulted in significantly reduced health-related quality of life and declines in independent living among older adults (Inaba et al., 2003). Serious injuries—regardless of hospitalization status and baseline characteristics such as age, health status, and functional limitation—also dramatically increased Medicare spending on both injury and noninjury-related health care for at least several years after injury incidence (Carter & Porell, 2011). We found only one study (Porell & Carter, 2012) that examined the long-term consequences of all-cause nonfatal injuries including minor injuries. This study used a sample of 12,031 participants with continuous Medicare eligibility not enrolled in managed care who entered the Medicare Current Beneficiary Study between 1998 and 2001, and followed participants for 4 years following study entry. They found that serious nonfatal injuries raised the short- and long-term risks of institutionalization and mortality. Minor injuries did not raise short-term mortality or long-term institutionalization risk, but did raise the risks of short-term institutionalization and dying within 4 years of injury incidence. Although this study considered institutionalization and mortality risk, it did not consider other possible outcomes such as the risk of another injury or hospitalization risk and investigated mortality risks over a relatively short period of time.

We argue for the importance of assessing the long-term consequences of both serious and minor all-cause nonfatal injuries among older adults for three reasons. First, by excluding consideration of minor injuries, we ignore a large share of injuries sustained by older adults. More than 80% of medically attended nonfatal injuries do not result in hospitalization (Xu & Drew, 2016) and in 2014, nearly 75% of older adults seeking care from an emergency room for their injuries were treated and released without hospitalization (CDC, 2016b). Second, studies of minor all-cause injuries and specific injury demonstrate that minor injuries are associated with long-term declines in physical functioning, even after controlling for baseline health status (Edwards, Song, Dunlop, Fink, & Cauley, 2010; Porell & Carter, 2012). The after-effects of minor injuries may resemble those of severe injuries, and similar health burdens may lead to morbidity and mortality consequences akin to those observed among older adult survivors of serious injuries (Carter & Porell, 2011). Third, making minor injuries the target of public health intervention may present a significant opportunity to reduce nonfatal injury impacts: one of the most important predictors of falls is a previous fall (Asada et al., 1996; Bergland & Wyller, 2004; Tromp et al., 2001; Yamashita, Noe, & Bailer, 2012).

We extend previous research on the long-term consequences of minor and serious all-cause nonfatal injury in several ways. First, we consider the incidence of additional injury and later hospitalization as key outcomes, in addition to mortality. In 2013, older adults accounted for 35% of all hospitalizations (U.S. Department of Health and Human Services, 2016a), but only 14% of the U.S. population (U.S. Census Bureau, 2014). Their hospital stays were longer on average compared with younger hospital patients and resulted in more than 42% of the national hospital bill in 2011 (Weiss, Barrett, & Andrews, 2014). The hypothesized mechanism linking nonfatal injuries with later health and mortality consequences is a possible long-term or permanent reduction in health status and/or functional capacity (Inaba et al., 2003; McGwin, MacLennan, Fife, Davis, & Rue, 2004; Tinetti & Williams, 1998) making individuals less resilient to additional health insults. Injurious events, such as falls, episodes of overexertion, or motor vehicle accidents, can produce contusions, open wounds, sprains, or fractures that lead to pain, fatigue, and limitations in balance, mobility, grasp, reach, and strength (Inaba et al., 2003; Tinetti & Williams, 1998). Beyond physical limitations, injured persons can engage in further restriction of activity due to a fear of re-injury (Zijlstra et al., 2007), engendering, or compounding declines in emotional and psychological wellbeing and social role functioning (Inaba et al., 2003). Reduced health status, functional capacity, and mental wellbeing resulting from injury can lead to a diminished ability to withstand health complications resulting from injuries, like infections or skin ulcers, and make it less likely to recover baseline functional capacity and health (Holbrook, Anderson, Sieber, Browner, & Hoyt, 1999). We argue that this potentially long-term drop in functioning and resilience can heighten the risk of additional injury and major episodes of health care. Through this same pathway, nonfatal injury may also reduce the number of remaining years of life, leading to premature mortality (Porell & Carter, 2012; Richmond, Kauder, Strumpf, & Meredith, 2002). Examining how nonfatal injury may be related to later health and mortality consequences is especially relevant for older adults; they may experience a more severe and persistent increase in frailty compared to younger individuals, and the decline in health may be more likely to be permanent.

Second, we extend the period of mortality follow-up by drawing upon survey data linked to the National Death Index (NDI), allowing us to observe deaths occurring up to 11 years after the initial interview. Third, we use a recent, large, and nationally representative sample of the U.S. noninstitutionalized civilian population. In addition, this study examines the risk of later injury, hospitalization incidence and duration, and mortality for older adults who sustained a nonfatal injury (serious and minor) compared to non-injured older adults.

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