We are unaware of any previous study that has assessed the influence of alcohol use on the HR-QoL in severely injured patients. In our study, we found that in severely injured patients HR-QoL was lower before injury in those patients with positive BAL upon admission compared with those patients with negative BAL. The reported HR-QoL one year after trauma was also lower in patients with positive BAL; however, the difference was not statistically significant. The overall decrease in HR-QoL was slightly lower in patients with positive BAL than in patients with negative BAL. When compared to age-specific population norms, patients with negative BAL upon admission reported notably higher pre-injury HR-QoL (p= 0.01) than patients with positive BAL. Age-specific population norms in both groups were similar. However, when comparing mean HR-QoL one year after injury to age-specific HR-QoL between the two groups, the difference was minimal.
One year after injury, the main reported problems by EQ-5D dimension were related to pain and discomfort or having problems during usual activities and with mobility. Almost half of the severely injured patients in the current study reported having problems in these three dimensions. Interestingly, patients who had positive BAL at admission, reported less anxiety and depression after injury than before. It remains unclear to which degree this finding is related to the post-traumatic condition and to possible changes in the individual’s alcohol use. The mean blood alcohol content in the BAL positive trauma patients was 1.9 g/L, which is highly suggestive of hazardous drinking behaviour (21). In the other HR-QoL dimensions, the problems were less common before the injury than after.
It is a common occurrence that injury victims report pre-injury HR-QoL that exceeds age-specific population norms (30). In our study, this was, however, only apparent in patients with negative BAL, whereas in patients with positive BAL we noticed the opposite. As has been previously suggested (4, 9), we also noticed that post-injury HR-QoL remained lower than the age-specific population norm.
The potential negative impact of excessive alcohol consumption on a person’s HR-QoL is well established (16, 17). Therefore, we propose that one possible explanation for the reported reduction in anxiety and depression could be a reduction in alcohol use after the injury happened. As has been previously shown by Pagulayan et al. (31), injured BAL positive patients often reduce their alcohol use after the injury, although it was not possible for us to verify this reduction.
One of the current study’s obvious limitations is its retrospective nature. However, all the information about the patients’ HR-QoL was prospectively collected during the patients’ stay in ICU/HDU, and follow-up was done by phone by a study nurse. Patient inclusion to the study cohort was determined retrospectively by a pre-specified injury severity score (NISS) ≥16, and data on alcohol use were retrospectively collected from the records.
After excluding patients that had died within one year of trauma, the total response rate for the study was 56%. It should be noted that when studying severely injured patient groups with a mortality rate of over 10%, even when patient survives for at least one year, the injury itself can be a limiting factor (for example, severe head trauma, etc.) that prevents further participation in the study protocols. A significant proportion of patients expressed a hazardous use of alcohol that could also have had effect on the attrition rate. Therefore, a response rate of 56% can be considered to be relatively satisfactory. Moreover, when comparing our response rate to that reported in earlier studies, it is clear that low response rates are a common occurrence (4-6, 9) in studies regarding post-injury quality of life. Furthermore, the attrition rate has been shown to become even greater as time passes by (11).
The testing for alcohol in the current study was not systematic due to the constraints of Finnish legislation. This can therefore be considered a potential limitation and a source of inherent bias in study. Conversely, the rate of alcohol use in the whole study population (34%, mean BAC of 1.9 g/L) is in agreement with previous findings regarding alcohol use in various trauma patients (13, 19, 32). Furthermore, as the suspicion of alcohol use in trauma patients is usually high, we believe that it is unlikely that any significant alcohol use would have been missed by paramedics at the injury site or later by nurses and physicians in the ER or ICU. However, we acknowledge that this is a limitation and a possible source of bias.
As with all retrospective studies regarding post-injury quality of life, some common mechanisms of biases should be discussed. When pre-injury HR-QoL is measured after the incident, the evaluation is inherently at risk of recall bias, meaning that injury patients may remember their pre-injury HR-QoL better or worse than it actually was (33). Generally, the risk of recall bias grows as time passes. However, in the current study the data collection started early in the ICU/HDU, which is likely to have reduced the risk of recall bias. Injury victims are also at risk of transition shift, meaning that the victims’ perceptions of HR-QoL are altered because of a change in the victims’ internal standards, values and conceptualisation (34).
The definitive strength of this study is that all data on HR-QoL were prospectively collected at the ICU/HDU of a single large hospital that is responsible for all the major trauma patients in its catchment area. In like manner, the data collection started at the earliest possible time in the ICU/HDU, which is likely to have reduced the risk of recall bias. Furthermore, despite a somewhat limited response rate, a great deal of effort was made to contact patients one year after injury. HR-QoL was evaluated with the EQ-5D questionnaire, which is widely used generic instrument. EQ-5D is also easy to complete and it is a commonly used and accepted instrument for the evaluation of post-injury QoL.