Article Text

Monetised estimated quality-adjusted life year (QALY) losses for non-fatal injuries
  1. Gabrielle F Miller1,
  2. Curtis Florence1,
  3. Sarah Beth Barnett1,
  4. Cora Peterson1,
  5. Bruce A Lawrence2,
  6. Ted R Miller2
  1. 1 National Center for Injury Prevention and Control, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
  2. 2 Pacific Institute for Research and Evaluation, Calverton, Maryland, USA
  1. Correspondence to Dr Gabrielle F Miller, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA; ygm3{at}cdc.gov

Abstract

Background Quality-adjusted life years (QALYs) provide a means to compare injuries using a common measurement which allows quality of life and duration of life from an injury to be considered. A more comprehensive picture of the economic losses associated with injuries can be found when QALY estimates are combined with medical and work loss costs. This study provides estimates of QALY loss.

Methods QALY loss estimates were assigned to records in the 2018 National Electronic Injury Surveillance System - All Injury Program. QALY estimates by body region and nature of injury were assigned using a combination of previous research methods. Injuries were rated on six dimensions, which identify a set of discrete qualitative impairments. Additionally, a seventh dimension, work-related disability, was included. QALY loss estimates were produced by intent and mechanism, for all emergency department-treated cases, by two disposition groups.

Results Lifetime QALY losses ranged from 0.0004 to 0.388 for treated and released injuries, and from 0.031 to 3.905 for hospitalised injuries. The 1-year monetary value of QALY losses ranged from $136 to $437 000 among both treated and released and hospitalised injuries. The lifetime monetary value of QALY losses for hospitalised injuries ranged from $16 000 to $2.1 million.

Conclusions These estimates provide information to improve knowledge about the comprehensive economic burden of injuries; direct cost elements that can be measured through financial transactions do not capture the full cost of an injury. Comprehensive assessment of the long-term cost of injuries, including quality of life losses, is critical to accurately estimate the economic burden of injuries.

  • quality of life
  • costs
  • multiple injury

Data availability statement

Data are available upon reasonable request. Data may available through relevant data sharing requests.

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Background

In order to generate a more complete estimate of the economic burden of injuries, it is necessary to include an estimate of the quality of life lost as a result of injury. The quality-adjusted life year (QALY) is a measure of disease or injury burden that captures both the quality and the duration of life lived post disease or injury. QALYs, either monetised or unmonetised, are used in studies of injury costs and of treatment and prevention benefits from many perspectives, including those of society, of victims and their families, and of the healthcare system, when analysing its ability to cost-effectively produce and preserve health. In analyses of preventive intervention, the expected QALY gain represents the unmonetised or monetised value of injury risk reduction across a target population.

In 2013 it was estimated that non-fatal injuries accounted for over $456 billion in lifetime medical and work loss costs in the US.1 In 2018 an estimated 23 million injuries were seen in an emergency department (ED).2 Injuries are classified by intent, either as unintentional, violence-related or undetermined, and have several mechanisms, such as poisoning, falls and MVC.3 The total lifetime economic burden of injury differs by mechanism and intent. For example, in 2013 it was found that the total lifetime costs of unintentional injuries were more costly than assault or self-harm injuries.1 Further, costs of injuries also differ at the per-event level by disposition (ie, includes treated and released vs hospitalised). All types of injuries had a higher associated cost when they occurred in visits with hospitalisation.1

QALYs provide a means to compare different types of injuries using a common measurement which allows incorporation of the quality of life and duration of life from an injury to be considered. When QALY estimates are combined with medical and work loss costs, they can help to provide a more comprehensive picture of the economic losses associated with injuries. A QALY typically takes a value between 0 and 1, where 0 represents death and 1 represents perfect health. A loss of 1 QALY is equivalent to losing 1 year of life in perfect health.

There is limited literature on overall QALY losses for injuries in the US. Previously published literature identifies QALYs for traumatic brain injury4 or road injuries.5 6 Additionally, there is research that identifies QALY losses in European countries.7 There is literature that identifies quality of life cost for hospital-treated non-fatal injuries; however, it does not produce individual QALY loss estimates for specific injuries.8 The present study contributes to the literature in three key ways. First, to our knowledge this is the first study in 25 years to produce QALY loss estimates for non-fatal injuries by type of injury and the second study to estimate QALY loss associated with non-fatal injuries in the US by mechanism, intent and disposition, classifications that are meaningful to US injury public health. Additionally, this study uses data on hospital ED visits from the National Electronic Injury Surveillance System - All Injury Program (NEISS-AIP), which has a higher level of detail on injuries and uses trained coders for injuries, leading to better accuracy of diagnosis codes, allowing for greater precision in matching with QALY values. Finally, this study provides contemporary estimates of QALY loss with data from 2018. This study deals strictly with non-fatal injuries so its QALYs do not include a mortality measure.

Methods

QALY loss estimates were assigned to records in the 2018 NEISS-AIP, the most recent year of data available at the time of analysis. The NEISS-AIP collects data on initial visits for non-fatal injuries treated in a hospital ED. Visits were classified into two dispositions: treated and released, and hospitalised (which includes transfers). Visits classified as observations, leaving against medical advice or unknown were removed from the data set.

QALY estimates by body region and nature of injury were assigned in four stages using previously published research methods.5 9 Stage 1 used the Hirsch and Eppinger10 ratings by an expert panel of physicians who reported functional capacity losses over time for most injuries listed in the Abbreviated Injury Scale, 1980 Revision (AIS-80).11 The Hirsch expert panel deliberately restricted its ratings to functional capacity losses, as these are objective medical facts. The panel recognised that it did not have expertise on the effects of injury on role function (usual activities) and that psychological impacts of injury were determined by details of the injury event and the injury victim’s behavioural health and resiliency preinjury, as well as physical losses, meaning they were not predictable by diagnosis. The panel rated physical impairment nature and duration by diagnosis along six dimensions of functioning: mobility, cognitive, cosmetic, sensory, pain and daily living. Each dimension was defined by four levels of impairment: slight, moderate, severe and maximum or total. The panel described the typical recovery trajectory based on the time spent at each level of impairment during the first year after injury, in years 2–5 and in year 6 onwards. It also assessed variations in recovery trajectory by patient age.

AIS-1 injuries, which are the least severe injuries (eg, contusions, abrasions),10 and non-traumatic injuries (such as non-severe and hospital-admitted burns, submersion, lead poisoning, frostbite and electric shock) were not mapped by Hirsch and Eppinger.10 AIS-1 injuries were assigned an impairment of 0 in this stage.5 Other sources provided impairment ratings for the non-traumatic injuries.12–14 Online supplemental appendix provides further information and an example.

The second stage added a seventh role-oriented dimension, work-related disability, to the six dimensions of physical functioning. This dimension was calculated using the same work disability values previously used to estimate work loss for the Web-based Injury Statistics Query and Reporting System (WISQARS).15 These values are based on temporary and permanent disability data from more than 450 000 worker injuries. This seventh dimension constitutes the only QALY loss estimated for AIS-1 injuries.

In the third stage, health-related utility weights were assigned to each level of each dimension of functional capacity loss and to the work-related role loss. These weights had been determined through a systematic review of utility-based QALY scoring literature.6 The review determined medians of utility scores that preference-based questionnaires assigned to the dimensions and functional loss levels included in the QALY assessment.

Because the WISQARS cost framework explicitly values the wage loss resulting from non-fatal injury, to avoid double-counting, the utility weight associated with the percentage of earning capacity lost to an injury was calculated as net of earnings loss and represents the value, for example, of social interactions in the workplace and feeling productive. In removing the income loss, the utility weight calculation for work disability relies on the value of statistical life (VSL), which is the amount that a large group of people are willing to pay in the expectation of saving one life. This value was calculated using the VSL prescribed by the US Department of Health and Human Services of $9.6 million in 2014 dollars.16 Additional information and an example can be found in the online supplemental appendix and elsewhere in more detail.14

Finally, impairment estimates were merged with the 2018 NEISS-AIP data by admission status (treated/released and hospitalised), NEISS injury diagnosis and body part,17 age group (0–15, 16–45, 46–65, >65), and three mechanism or intent categories: traffic, violence and all others. QALY estimates were calculated by intent and mechanism. Injuries were grouped by intent (unintentional/unknown/undetermined and violence-related), where violent intents were further classified into assault, self-harm and legal intervention. QALY losses were calculated using NEISS injury diagnosis, body part and age group. Estimates were produced by intent and mechanism, for all ED-treated cases, by two disposition groups: treated and released, and hospitalised. Life expectancy was discounted by 3% and based on the life tables published by the National Center for Health Statistics.18 QALYs were calculated for 1 year and lifetime loss. In addition, the QALY loss per injury was monetised by multiplying by a value of $530 000 per QALY.19 SAS V.9.4 was used to conduct all statistical analyses. The public was not involved in the design of this secondary analysis of existing data sets.

Results

Table 1 reports the average estimated QALY loss and cost per non-fatal injury by intent and ED disposition. A person with an injury of unintentional/unknown/undetermined intent who is treated and released is estimated to lose an average of 0.093 QALY during the year following the injury. This first-year QALY loss is valued at almost $50 000. Those with a violence-related injury who are treated and released had first-year QALY losses between 0.018 and 0.155 years, with an estimated monetary value between $9700 and $82 000. A similar pattern holds for those who are hospitalised as a result of their injury. A person hospitalised with an injury of unintentional/unknown/undetermined intent is estimated to lose an average of 0.241 QALY during the year following the injury, with an estimated monetary value of almost $128 000. Those with a violence-related injury who are hospitalised had first-year QALY losses between 0.045 and 0.255, with a monetary value between $24 000 and $127 000. Lifetime QALY losses ranged from 0.033 to 0.300 for treated and released injuries, and from 0.119 to 0.550 for hospitalised injuries. The lifetime monetary value of QALY losses for hospitalised injuries ranged from $63 000 to $292 000.

Table 1

Average estimated QALY loss and cost per non-fatal injury by intent and emergency department visit disposition, 2018 NEISS-AIP (2018 US dollars)

Table 2 reports the average estimated QALY loss and cost per non-fatal injury by mechanism and ED disposition among all intents of injury. Among those who were treated and released, 1-year QALY losses ranged between 0.000 for drowning/submersion and 0.178 for falls. The associated monetary losses ranged from $136 to $94 000. Similarly, lifetime QALY losses among those treated and released ranged from 0.000 for drowning/submersion to 0.388 for falls, resulting in a monetary loss ranging from $231 to $206 000. Among those hospitalised, 1-year QALY losses ranged from 0.018 for poisoning to 0.824 for drowning/submersion, resulting in monetary losses ranging from $9400 to $437 000. Lifetime QALY losses for those hospitalised ranged from 0.031 for poisoning to 3.905 for drowning/submersion; monetary losses ranged from $16 000 to $2.1 million.

Table 2

Average estimated QALY loss and cost per non-fatal injury by mechanism and emergency department visit disposition among all injury intents, 2018 NEISS-AIP (2018 US dollars)

Among those with unintentional injuries that were treated and released, 1-year and lifetime QALY losses were lowest for drowning, poisoning, foreign body and inhalation/suffocation (0.000–0.009) (data not reported). Among those hospitalised, 1-year QALY losses were lowest for poisoning, inhalant, foreign body and other specified (0.018–0.081), and lifetime QALY losses were lowest for poisoning, foreign body, dog bite and other specified (0.027–0.148). The highest 1-year treated and released QALY losses were for pedal cyclist and fall (0.127–0.178), and lifetime QALY losses were highest for pedestrian, other transport and fall (0.246–0.388). The highest 1-year hospitalised QALY losses were for pedestrian, fall and drowning (0.357–0.824), and lifetime QALY losses were highest for pedestrian, fall and drowning (0.753–3.906).

Among those with violence-related injuries that were treated and released, 1-year and lifetime QALY losses were lowest for drowning, poisoning, foreign body and machinery (0.000–0.005) (data not reported). Among those hospitalised, 1-year and lifetime QALY losses were lowest for poisoning, natural/environmental, foreign body and other specified (0.014–0.078). The highest 1-year and lifetime treated and released QALY losses were for other transport and fall (0.200–0.446). The highest 1-year and lifetime hospitalised QALY losses were for pedal cyclist and drowning (0.825–3.885).

Discussion

This study provides quality of life loss values and monetary valuations by both injury intent and injury mechanism using the NEISS-AIP. These estimates are valuable in public health approaches that address injuries by mechanism and intent—for example, self-harm and suicide, homicide, falls, and motor vehicle injuries. Additionally, they provide information to improve knowledge about the comprehensive economic burden of injuries; direct cost elements that can be measured through financial transactions, such as medical care and lost work productivity, do not capture the full cost of an injury. In addition, estimates by injury type can help to quantify per-person experiences with injuries over the long term, contributing to expanded analysis opportunities to compare comprehensive long-term injury costs with the cost of public health injury prevention efforts.

This study is subject to at least three limitations. First, these estimates are specific to an important and long-standing non-fatal injury surveillance system, the NEISS-AIP. This study’s estimates will allow researchers to accurately and systematically describe the quantity and value of quality of life losses reported in this data source. Since the NEISS-AIP is an ED-based sample, it excludes injuries treated in non-hospital settings, such as doctors’ offices or urgent care, and those admitted directly to a hospital without an ED visit. Thus, these estimates do not include those treated outside the ED or who did not seek medical care. Second, ideally the QALY losses over time for each of the hundreds of injuries assessed would be determined by enrolling statistically valid patient samples by diagnosis and tracking their recovery longitudinally. This effort would be prohibitively expensive and burdensome. Instead, we built QALY losses by applying utility-based QALY weights to physician reports of objectively measurable functional losses and administrative data on work-related role impairment. Those clinical reports of typical recovery arcs are several decades old10; they might not accurately reflect current recovery arcs, given advances in medicine since 1983. Although more recent studies of injury impairment have surveyed patients directly about their experiences20 or used general population surveys to rank impairment descriptions of different health states,21 these studies covered only modest numbers or broad categories of injury. Preliminary comparisons of selected broad diagnosis groups, however, suggest that if anything the clinical estimates of functional recovery were overoptimistic. Finally, only one diagnosis per injury episode was taken into account in estimating QALY losses; in the case of a person with multiple injuries, the estimates presented here likely undercount quality of life losses.

Conclusion

Quality of life losses are an important element in public health analysis of illness and injuries. Estimates presented here indicate that the total cost of injuries extends beyond direct costs such as medical care and lost work productivity. Comprehensive assessment of the long-term cost of injuries, including quality of life losses, is critical to accurately estimate the economic burden of injuries.

What is already known on the subject

  • Quality-adjusted life years (QALYs) provide a means to compare different types of injuries, incorporating the quality of life and duration of life from an injury.

  • The total lifetime economic burden of injury differs by mechanism and intent.

What this study adds

  • This study uses data on hospital emergency department visits from the National Electronic Injury Surveillance System - All Injury Program, allowing for greater precision in matching with QALY values.

  • This study produced contemporary QALY loss estimates for non-fatal injuries in the US by type of injury and by mechanism, intent and disposition.

Data availability statement

Data are available upon reasonable request. Data may available through relevant data sharing requests.

Ethics statements

Patient consent for publication

Ethics approval

Not applicable.

References

Footnotes

  • Contributors GM conceptualised the study, drafted the manuscript and reviewed the final manuscript. CF conceptualised the study and revised/reviewed the final manuscript. SBB and CP drafted the manuscript and reviewed the final manuscript. BL and TRM conceptualised the study, conducted the analysis and reviewed the final manuscript. All authors edited the manuscript and approved the final manuscript as submitted.

  • Funding This work was partially funded by a contract with the CDC (75D30118P01557).

  • Disclaimer The findings and conclusions in this manuscript are those of the authors and do not necessarily represent the official position of the CDC.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.