Return to work is undoubtedly one of the most significant outcome measures after severe accidental injury. Indirect costs associated with injury exceed direct costs of treatment and sick-leave following accidental injury is a major contributor to the total burden of health care costs [2
]. The relevance of psychosocial and subjective factors for a successful return to work is increasingly recognized [4
] and from chronic back pain patients it is known that the longer individuals refrain from work, the lower the probability of returning to work [21
One year after accidental injury we could show that patients' self-reported appraisal of injury severity and of patients' ability to cope with the accidental injury and its job-related consequences were the strongest predictors of return to work [5
]. Injury severity and the type of accident which were also predictors at one year, no longer contributed to the prediction at the follow-up. At three years only patients' appraisal of injury severity and of patients' ability to cope remained predictive - independent of each other and of objective injury severity measured by the ISS as bivariate correlations show.
We anticipated that the patients' appraisal of injury severity and their own ability to cope with the accidental injury and its job-related consequences would still contribute to the prediction of time off work at three years but we anticipated less impact. In fact, the difference between the 4 groups actually increased at three years. In the first year medical treatment and rehabilitation contributed significantly to days off work (Table ), whereas in the second and third year after the injury, factors not related to the accidental injury gained influence.
These results are in line with Lazarus' theories on stress, appraisal and coping [13
]. Lazarus emphasized the significance of the primary and secondary appraisal of a stressful situation. In the primary appraisal the situation can be judged as harmful, as a threat or as a challenge. The same situation can be appraised differently by different individuals. The secondary appraisal is the person's judgment of his/her ability to cope with a situation and this depends on the person's individual coping strategies. When a stressful situation is appraised as controllable by action, problem-focused coping will predominate, whereas where a situation is viewed as refractory to change, emotion-focused coping is more likely to predominate. Coping is increasingly viewed as a process rather than a style and can change over time in accordance with the situational context [13
The fact that injury severity was no longer predictive at the three year follow-up needs further explanation. Findings from other studies on this point are not consistent. Time off work in severely injured accident victims correlated with physical impairment in some studies [2
] whereas there was no correlation with injury severity in others [6
]. In work related low back injuries and hand trauma, objective measures of physical impairment correlated with return to work but were less important than psychosocial factors [7
]. Contrary to our findings, Soberg et al. found that injury severity after severe multiple injuries was higher in the non-return to work group at 2-years follow-up but not at one year [4
]. The one year results were interpreted so that the contribution of time of hospitalization and rehabilitation was more important in the first year. In our sample we also observed that in the first year post accident the length of hospitalization contributed significantly to the time off work, whereas in the following years this was no longer relevant. An important reason for the divergent results could be the exclusion of severe brain injury in our sample. 36% of the patients in the Soberg study had sustained a head/neck injury, 18% had a spinal cord injury. It might be hypothesized that in these types of injury the injury severity has more impact on the functional outcome and on return to work than in non-neurologic injuries. McKenzie et al. [2
] excluded patients with major neurologic injury and still found a correlation between injury severity and return to work, but this correlation was weak. Impairment at hospital discharge and in the follow up assessments better predicted return to work than the initial injury severity.
The fact that in our study injury severity was no longer predictive of the time off work may be partially explained by an overall high ISS score in the study sample. All the participants in the study were severely injured and therefore did not fully represent the whole spectrum of victims of accidental injuries.
Advanced age, which is generally regarded as a risk factor for non-return to work [2
], was not predictive in our study. This result is in accordance with the Soberg study [4
]. Our sample's relatively low proportion of workplace accidents, where age might have a greater impact on outcome, could be one reason for this finding [9
The general impact of patients' personal expectations and health beliefs on health outcome is increasingly recognized. A review found correlations between positive expectations and better health outcome for different medical conditions [12
]. After major limb trauma, one of the most important predictors of rate of return to work was work self efficacy or the patients' belief that they are able to return to work [26
]. Patients who sustained multiple injuries and returned to work two years after the accidental injury scored higher on internal health beliefs, i.e. they believed they had some influence on their own wellbeing. Patients who did not return to work scored higher on external health beliefs, i.e. they believed their health was dependent on "powerful others" or factors beyond their influence [4
]. In patients who sustained traumatic injury patients' characteristics like higher level of education, high levels of social support, job stability, white collar employment and employment in jobs with low physical demands and good benefits were associated with higher rates of return to work [2
]. All these factors can have an influence on patients' appraisal of their coping abilities. In low-back pain patients their prediction of outcome and return to work is of high prognostic value [22
], and following myocardial infarction patients' initial positive beliefs concerning their illness favored return to work [28
Mayou et al. found in a three-year follow-up after motor vehicle accidents that psychological factors, persistent medical and financial problems and ongoing litigation were important predictors of chronic posttraumatic stress disorder whereas psychiatric outcome and pain were no longer related to the initial injury severity. One out of three patients in this sample developed a psychiatric complication [29
]. Despite these findings, psychiatric or psychological assessment is uncommon in victims of accidental injuries and the main focus is still on the pure somatic treatment. The poor outcome of many accident victims, independent of the objective severity of the injury, confirms the importance of early psychological assessment and, where needed, treatment and the provision of practical advice and information [29
]. Michaels et al. state that psychological morbidity following injury impedes return to work. Despite the observation of a gap between physical outcome and return to work, the management of psychological and social consequences of injury is still neglected [6
Some limitations of this study have to be addressed. The sample included only severely injured accident victims and whilst the homogeneity of the sample helps in the interpretation of the results, it also increases the likelihood that the results may not be generalized to apply to patients with less severe injuries.
We excluded patients with pre-existing somatic and psychiatric morbidity in order to achieve a sample as homogenous as possible and to reduce the possibility of the outcome being influenced by factors other than the accidental injury. By excluding patients with pre-existing somatic and psychiatric morbidity we possibly excluded patients who were at higher risk for sick-leave following accidental injury. Knowledge of the German language as an inclusion criterion might have led to the exclusion of participants who were less well socially integrated, a risk factor for work disability. It can be hypothesized that insufficient proficiency in the German language would have resulted in greater difficulties in dealing with the consequences of accidental injuries and, therefore, longer time off work. The question remains whether such an outcome would be mediated by the patients' appraisals or other factors related to the knowledge of the German language, such as the level of education. In a follow up study non-German speaking participants were included and interviewed using interpreters and translated questionnaires. There was no significant difference between German speaking and non-German speaking participants with regard to PTSD symptoms [31
There were 31 drop-outs from T1 to T3. At the 12 months follow up (T2) data from 15 patients who did not participate at the 3-year follow-up (T3) was available. However, these 15 participants did not significantly differ from the final sample. There was lower appraisal of the injury severity and a non-significant trend to less time off work in these drop-outs. Patients with a higher risk for longer sick-leave were, therefore, well represented in the final sample and the drop-outs probably did not affect the results substantially.
The number of days off work was assessed in the interviews by patients own self-rating. Strict data privacy protection laws in Switzerland prevent the use of health insurance companies' data for the purpose of research projects. That data, of course, would have been more reliable.