One year following injury, pain and physical factors affect the likelihood of residual disability, but psychiatric symptoms may have a greater influence
- School of Health and Social Services, College of Health, Massey University, Palmerston North, Manawatu, New Zealand
- Correspondence to : Associate Professor Sarah Derrett, School of Health and Social Services, College of Health, Massey University, Private Bag 11–222, Palmerston North, Manawatu 4442, New Zealand;
Implications for practice and research
Disability among participants hospitalised for injury is prevalent 12 months after injury.
Opportunities exist for research into improved screening for pain and psychiatric symptoms among injured patients, and also to test interventions for their capacity to inform policy and improve disability outcomes.
Internationally, there is increasing interest in understanding disability following injury.1 ,2 Much research has been concentrated on physical rather than mental disability outcomes. O’Donnell and colleagues aimed to document the level of disability experienced 12 months after an injury that resulted in hospitalisation for a period of over 24 h. They also examined the interactions between acute and 12-month injury characteristics, pain, psychiatric symptoms and disability according to the 12-item version of the WHO Disability Assessment Schedule (WHODAS II).
The potential participants were injured Australian residents hospitalised for more than 24 h; the majority (66%) had been injured as a consequence of a motor vehicle crash. Of 3771 potential participants, 1590 were invited; data were available for 1010 (64%) of whom 715 (71%) were followed for a period of 12 months postinjury.
Preinjury and postinjury disability was assessed using the WHODAS II. Additional data collected included a history of preinjury psychiatric diagnoses, anatomical injury severity score (ISS), hospital length of stay, intensive care unit admission and discharge to a rehabilitation unit; post-traumatic stress disorder, anxiety/depressive symptoms (acutely and at 12 months postinjury) and pain.
Structured equation modelling was used to examine the relationships between injury characteristics, psychiatric symptoms (acutely and at 12 months) and disability 12 months postinjury.
The prevalence of disability 12 months postinjury was up to four times that reported by the general population. Injury characteristics and pain both contributed to disability, but psychiatric symptoms (12 months postinjury) had the strongest relationship with disability.
The researchers suggest that a limitation of their research was the use of self-reported measures, suggesting that a clinician-assessment of disability or other ‘objective’ measures such as return to work would be an improvement. While clinical outcomes are undoubtedly important, the measure of disability used in this study was appropriate. It is difficult to envisage how, in the context of clinic visits, clinicians can better ascertain disability outcomes than the participants themselves. Also, while it would be interesting to see research investigating paid employment outcomes, employment is not necessarily a more ‘objective’ measure, being affected by the existence of vocational rehabilitation programmes, trade agreements, the vagaries of global recession and social capital available to the injured.
It would be useful if the authors had provided additional detail about the model development. In contrast to their prior research,3 weak relationships exist between early psychiatric symptoms and disability at 12 months, yet strong indirect relationships are apparent between concurrent 12-month psychiatric symptoms and disability. However, rather than ‘psychiatric symptoms (being) an important driver of long-term disability in injury patients’ (p141), perhaps disability is driving concurrent psychiatric symptoms?
The researchers help address a gap in our understanding of disability following injury. Their finding that disability outcomes were not largely explained by injury characteristics, including the ISS,4 an anatomical measure of injury severity, resonates with results emerging from another longitudinal study.5 Given that measures such as the ISS are calculated in response to mortality outcomes rather than disability outcomes, this is not altogether surprising. Instead we see that relationships exist between disability and pain and psychiatric symptoms. Both pain and psychiatric symptoms provide opportunities for intervention. The researchers’ call for research into improved screening and interventions to inform policy efforts in the important, but too-often overlooked, area of injury-related disability is timely.