Long-term mortality following injury in working-age adults: a systematic review

The impacts of injury at the individual, community and societal levels: a systematic meta-review

OBJECTIVES

Injury is a major public health problem. While the impacts of injury on the injured person are well documented, there is relatively little knowledge about the impacts of injury on those individuals and groups in the community connected to the injured person. This study seeks to describe this breadth of research using a meta-review methodology.

STUDY DESIGN

Systematic meta-review.

METHODS

To gain a better understanding of the known impacts of injury on family, community and society, a systematic meta-review of injury outcomes research literature was conducted. Seventy-eight peer-reviewed published literature reviews were included in the meta-review.

RESULTS

Of these, 70 reported outcomes at the level of the injured person including mortality, body functions, activity and participation limitations. Nine reviews reported impacts at the level of the community including impacts on family members, work colleagues and carers. Six studies reported impacts at the societal level including economic, health system and injury compensation system impacts.

CONCLUSIONS

In summary, the meta-review identified a substantial body of knowledge at the individual level outcomes of injury, and a relative lack of information regarding the community and societal impacts of injury. An injury outcome framework is proposed on the basis of the findings of the meta-review to guide future research activity, particularly with regard to injury outcome domains where there is currently limited evidence. A comprehensive framework that takes account of all levels of impact is necessary for effective policies, systems and strategies to support recovery following injury.

Long-term mortality risk in individuals with permanent work-related impairment

OBJECTIVES

Recent estimates indicate that at least one in five activity-limiting injuries occurs at work. Of individuals who suffer these injuries approximately 10% experience some degree of functional impairment. We were interested in investigating long-term mortality risk in individuals with permanent impairment from work injury and to examine whether work disability is a significant explanatory factor.

METHODS

We used a retrospective matched cohort methodology to examine differences in mortality rates between individuals with permanent impairment from a work injury and a group of non-injured controls over a 19-year period. We used a sample of impaired workers to investigate the impact of work disability on mortality risk using percentage of earnings recovery after injury as the key proxy measure. All analyses were stratified by sex.

RESULTS

Permanent impairment from a work injury was predictive of premature mortality in both male and female claimants, though the risk was slightly higher among women. Work disability was a key explanatory factor in the rate of death among impaired workers, the effects being more pronounced in men. We also found that higher impairment level was associated with mortality in men but not in women.

CONCLUSION

The study demonstrates the impact of permanent work-related impairment on longevity and identifies work disability as an important determinant of mortality risk. Given the disconnect between impairment ratings derived from standard diagnostic tools and labour-market activity after accident, more research is needed on the specific factors that contribute to work disability, particularly those related to psycho-social health and well-being.

Effect of comorbidity on length of hospital stay and in-hospital mortality among unintentionally injured patients

OBJECTIVES

Because comorbidity is a crucial issue in medical practice and research, this study evaluated the effect of comorbidity on the length of hospital stay and mortality among unintentionally injured patients.

METHODS

Korea National Hospital Discharge In-depth Injury Survey 2005 data were used, and the odds ratios for in-hospital mortality and long hospital stay were estimated for injured patients with and without comorbidity. The factors evaluated were the injury mechanisms; patient age, sex and residence; and hospital size.

RESULTS

In general, pre-existing diseases were associated with longer hospital stays after injury and increased the risk of death. Controlling for age, sex, residence, cause of injury and hospital size indicated that unintentionally injured patients with comorbidity experienced higher in-hospital mortality (OR=2.23) and longer hospital stays (OR=1.90). The greatest risk of death was associated with coagulopathy (OR=18.5) and fluid and electrolyte disorder (OR=13.8); the greatest risk of a long hospital stay was associated with Alzheimer's disease (OR=10.3) and paralysis (OR=5.8). The prognosis for cases involving drowning, traffic accidents and poisoning was most often affected by comorbidity (OR=15.1, 2.5, 2.5 for mortality). Comorbid patients injured in falls and fires were hospitalized 6.2 and 4.0 times longer, respectively, than those who did not have comorbid conditions.

CONCLUSIONS

It is necessary to identify and manage pre-existing disease among unintentional injury patients, and collaboration with other health care providers is important to the prognosis of injured patients.

Measuring the population burden of injuries--implications for global and national estimates: a multi-centre prospective UK longitudinal study

BACKGROUND

Current methods of measuring the population burden of injuries rely on many assumptions and limited data available to the global burden of diseases (GBD) studies. The aim of this study was to compare the population burden of injuries using different approaches from the UK Burden of Injury (UKBOI) and GBD studies.

METHODS AND FINDINGS

The UKBOI was a prospective cohort of 1,517 injured individuals that collected patient-reported outcomes. Extrapolated outcome data were combined with multiple sources of morbidity and mortality data to derive population metrics of the burden of injury in the UK. Participants were injured patients recruited from hospitals in four UK cities and towns: Swansea, Nottingham, Bristol, and Guildford, between September 2005 and April 2007. Patient-reported changes in quality of life using the EQ-5D at baseline, 1, 4, and 12 months after injury provided disability weights used to calculate the years lived with disability (YLDs) component of disability adjusted life years (DALYs). DALYs were calculated for the UK and extrapolated to global estimates using both UKBOI and GBD disability weights. Estimated numbers (and rates per 100,000) for UK population extrapolations were 750,999 (1,240) for hospital admissions, 7,982,947 (13,339) for emergency department (ED) attendances, and 22,185 (36.8) for injury-related deaths in 2005. Nonadmitted ED-treated injuries accounted for 67% of YLDs. Estimates for UK DALYs amounted to 1,771,486 (82% due to YLDs), compared with 669,822 (52% due to YLDs) using the GBD approach. Extrapolating patient-derived disability weights to GBD estimates would increase injury-related DALYs 2.6-fold.

CONCLUSIONS

The use of disability weights derived from patient experiences combined with additional morbidity data on ED-treated patients and inpatients suggests that the absolute burden of injury is higher than previously estimated. These findings have substantial implications for improving measurement of the national and global burden of injury.

Population health and clinical data linkage: the importance of a population registry

OBJECTIVE

The Australian National Collaborative Research Infrastructure Strategy supports development of a national research capability in population health and clinical data linkage. This paper illustrates the importance of incorporating a population registry within such a system using an example provided by the Manitoba Injury Outcome Study (MIOS) that quantified the long-term burden of mortality attributable to injury in working-age adults.

METHODS

MIOS is a population-based matched cohort study that used administrative health data from Manitoba, Canada. An inception cohort of injured cases (ICD-9-CM 800-995) aged 18-64 years was identified from all Manitoba hospital admissions between 1988 and 1991. A matched non-injured comparison group was randomly selected from the total provincial population using the Manitoba Population Registry. Mortality outcomes were obtained by linking the two cohorts with the deaths data over 10 years. Mortality rate ratios (MRRs) were calculated to compare the injured and non-injured cohorts.

RESULTS

A total of 21,032 matched pairs were identified. Using the population registry, the 10-year adjusted all-cause MRR comparing injured and non-injured cohort was 1.80 (95% CI 1.65-1.98). Without the registry, the unadjusted standardised morality ratio was 2.76 (95% CI 2.52-3.02).

CONCLUSIONS

The effect of injury on mortality outcomes was over-estimated using only the injured cases, without use of the population registry. Use of the population registry enabled the selection of a matched non-injured group for comparison purposes, ensured comprehensive follow-up of almost all participants, and provided more accurate estimates of exposure time, incidence of mortality and relative risk.