The present pilot study demonstrates the successful implementation of the recording of outcome parameters in the existing and well-established TraumaRegister DGU®. Moreover, first findings on hrQoL 12 months after severe injury in a larger cohort were obtained.

The systematic collection of data of severely injured patients in standardized registries has already led to considerable progress worldwide in terms of structural, procedural, and outcome-oriented quality assurance as well as in science. Hitherto, however, virtually all national data collections have been limited to the prehospital and clinical course until the patient is discharged from the respective acute trauma center. Previous outcomes-related post-discharge data collections have been limited either to smaller study populations or to specific injury patterns that are often predefined. This is making it impossible to draw conclusions about how to modify acute care, to improve functional outcomes, and to enhance hrQoL for survivors of severe injury. This gap in care research has already been identified by several research groups [22, 23]. In 2011, the Victorian State Trauma Registry (VSTR) and the “REcovery after Serious Trauma Outcomes, Resource use, and patient Experiences (RESTORE)” project allowed the first registry-based follow-up of severely injured patients to be collected at the state level in Australia [24, 25]. In this study, the available data were limited to a restricted period from July 2011 to June 2012 [24]. The EQ-5D-3L was used to describe hrQoL. In summary, based on their results, the authors were able to postulate that there is a high prevalence of persistent problems even 3 years after polytrauma and thus, the consequences of polytrauma should be considered a chronic condition.

As the first European registry, the TraumaRegister DGU® has succeeded in recording parts of the post-discharge progression of severely injured patients with the “ E) Outcome” [20]. Advantages of the registry-based data collection are the pseudonymized, standardized, and time-saving data collection. Furthermore, after completion of the pilot phase, an expansion to all trauma centers participating in the TraumaRegister DGU® and thus, a temporally unlimited follow-up of all patients recorded in the TraumaRegister DGU® would be possible.

During the pilot phase, data were collected by mail. The advantages of this type of survey are the data privacy compliant procedure and the cost savings, but mostly at the expense of the response rate. The average response rate in this study was 32%. A closer look at the response behavior shows a lower response rate among the younger patient groups (< 50 years). However, a non-response bias (selection bias) cannot be ruled as patients may not have responded because they were too ill, unable to complete the questionnaire, for example, as a result of arm/hand or head injuries, or as a result of depression and/or posttraumatic stress disorder. This could have affected the results as responding patients could have recovered better or faster than non-responders which might have led too overly positive results. The comparison with the literature shows that in polytrauma research the response rates are on average 50–58% also because a great part of patients died within the first two to five years post-injury [26, 27].

An e-mail- or app-based survey could address here especially the younger patient groups, be more cost-saving in the long term, and more flexibly applied in various languages [28]. By using different methods (postal, telephone, web-based), the response rate could certainly be increased. As expected, the response rate of patients with severe head injuries (AIS ≥ 2) was correspondingly lower.

In order to increase the response rate in the patient population examined, it would have been possible to use a proxy to answer the questionnaire. However, the use of proxies to answer the questions after polytrauma is rarely reported [14]. Injuries such as traumatic brain injuries may even require the use of a proxy. Proxy and patient questionnaires are analyzed equally but health status may differ in their responses [29]. In this context, Gabbe et al. showed that the differences between patients and proxy questioning show a random variability rather than systematic bias. Therefore, proxy questionnaires could suffer from bias when assessing the individual patient recovery, but they are unlikely to bias the group comparisons [30]. Hence, the utilization of proxies could enable the collection of outcome data after polytrauma, despite a risk of bias [31].

The examination of post-injury hrQoL is one of the central elements of the outcome questionnaire. The present results show that the younger the patient is at the time of the injury, the higher his physical sum score one year after polytrauma. In severe polytrauma with a high ISS, the physical perceived quality of life is statistically significantly impaired, where, on the other hand, the mental perceived quality of life shows no differences with respect to injury severity. Very severely injured patients are still physically limited 1 year after the injury, but with a well-compensated psyche. This also coincides with the satisfaction of the treatment outcome (Table 3). Patients with high injury severity (ISS > 50) are more satisfied than the average (Fig. 5). A similar conclusion was reached by the working group around Havermanns and colleagues [29]. Younger age and extremity injury were detected as short-term prognostic for a lower health status after a severe trauma. Whereas unemployment prior injury and comorbidities were shown to be long-term prognostic factors for a reduction in hrQoL.

A limitation of this pilot study is the use of a single generic instrument to measure hrQol, the SF-12. Ritschel et al. were able to show in their systematic review that there is a large variation in the assessment of patient reported outcomes after polytrauma, but the generic instruments SF-12 and SF-36 are the most widely used questionnaires in polytrauma research [14]. The introduction and further development of questionnaires such as the POLO chart as a specific polytrauma hrQoL tool based on patient- and expert- interviews is planned for future studies [32].