Skip to Content, Skip to Navigation

Safeguard OSH Solutions - Thomson Reuters

Safeguard OSH Solutions - Thomson Reuters

Safeguard Magazine

It’s academic—Injury outcomes

SARAH DERRETT reports on a major research project which challenges some common assumptions about injury outcomes and the return to work.

The recently passed Health and Safety Reform Bill has rightly focused attention on harms caused by workplace fatalities, including harms borne by workers’ families, friends and colleagues. Other important harms are the burdens borne by workers who survive an injury.

Assumptions are often held that person-level factors such as poor coping strategies or depressive symptoms lead to bad outcomes. But are these assumptions correct? If not, they may get in the way of our providing optimal rehabilitation for injured workers.

In 2007 a six-year study began at the University of Otago’s Injury Prevention Research Unit (IPRU) funded by the Health Research Council, with co-funding from ACC. The aim of the Prospective Outcomes of Injury Study (POIS), was to learn about injury survivors’ outcomes – and to see which factors predict good, and bad, outcomes.

Over a two-year period, 2856 injured people aged 18-64 were recruited to POIS (including 20% Māori) if they had an injury serious enough to require a week or more off paid work or considerable rehabilitation support. Most (92%) were in paid employment at the time of injury. For 36% of workers the injury happened at work; the rest were injured away from work. People were interviewed up to four times over a two year period. Interviews asked about lives before injury and then at each follow-up point about a range of things, including paid work, pain, bodily functioning, disability, and financial and social outcomes.

What, in fact, makes a difference to peoples’ outcomes?


POIS was able to consider outcomes for those hospitalised because of injury and those not hospitalised. (Overseas studies are usually limited to studying injured people at ED or hospital trauma units.) POIS found profound disability was more common three months post-injury among the hospitalised group (54%) compared to the non-hospitalised group (39%).

Nevertheless, finding 4 out of 10 of the non-hospitalised group with profound disability means we must not focus rehabilitation efforts solely on the hospitalised, particularly when one of the strongest predictors of disability was trouble accessing health services for their injury – something we can improve.

Two years after injury the percentage with profound disability was 13% in both the hospitalised and non-hospitalised groups. Good news: profound disability continued to reduce to 24 months post-injury. Bad news: 13% are still experiencing profound disability – more than twice the pre-injury proportion of 5%.


Return to work (RTW) is a desirable outcome. POIS found most (73%) were back in some form of paid work three months post-injury. Of course, this means 27% were not in paid employment. By 24 months post-injury 18% were not in work.

Is depression responsible for non-RTW? No. Apart from obesity, no health or psychological factors were related to non-RTW. Instead, factors such as poverty, manual occupation, physically difficult work tasks, long working weeks and temporary employment contracts increased the odds of non-RTW.

Good news: Rehabilitation actions in response to these potentially modifiable work organisation and tasks may help improve peoples’ RTW outcomes.


There exists a lay assumption that injured workers will “linger” on ACC because they can receive up to 80% of their wage while rehabilitating. As above, we know most people return to work quickly. However, POIS also tracked work pathways to 12-months post-injury and found that RTW was not always sustainable. Seven percent had RTW by 3 months but did not sustain this to 12 months; most of these people also had profound disability. Further, of those not RTW by 12 months, 80% had profound disability; others had “milder” disability. Even among those who RTW and sustained this out to 12-months, one-third were doing so despite profound disability.

Good news: injured workers are not “lingering” on wage compensation; instead they are getting back to paid employment despite profound disability.

Bad news: We are not yet using person-centred metrics, such as disability measures, to measure rehabilitation “success”. If we continue to focus solely on initial RTW, we are doing an injustice to those workers who cannot sustain work, and we are short-selling those who RTW despite profound disability.


New Zealand is right to be proud of our ACC system which followed the recommendations of Justice Owen Woodhouse over 40 years ago. The new HSW Act might improve the safety of the workplace; meanwhile POIS has identified opportunities for improving outcomes for those who do get injured. We hope future research by IPRU, and others, will extend the findings from POIS and ensure that rehabilitation strategies are guided by empirical evidence and not by assumptions.

Sarah Derrett is Director of the Injury Prevention Research Unit (IPRU) and Associate Professor (Health Systems and Public Policy) at the Department of Preventive and Social Medicine, Dunedin School of Medicine, University of Otago.

comments powered by Disqus

From Safeguard Magazine

Table of Contents