The aim of our study was to investigate the differences in the outcome of elderly polytraumatized patients compared to young patients with the same gender, ISS, mechanism of injury, GCS at admission, base excess and presence of coagulopathy.
Our main results after matching are as follows:
1. Mortality demonstrated no significant difference between geriatric and non-geriatric patients.
2. Length of stay demonstrated no significant difference between geriatric and non-geriatric patients.
3. Geriatric trauma patients had a significantly higher rate of complications.
Strengths/Limitations
The main strength of this study are the strict matching criteria which all are proven and validated predictors of outcome in trauma (20, 30–33). With this study concept we were able to study the effect of age on the outcome of severely injured patients.
The strongest limitation of this study lies within its nature as a retrospective register study. The available data is limited, and missing data cannot be accessed. Data concerning comorbidities or pre-existing medications is scarce. The follow up is limited to the in-hospital results. Therefore we cannot make any statements regarding long term mortality or morbidity. Furthermore, we could not match the pairs concerning comorbidities as they differed too much, or information was not sufficient.
A very surprising result of our study was the low rate of delirium in elderly patients. Whereas de Vries et al reported a delirium rate of 20.1% amongst elderly trauma patients (11), we only observed delirium in 2.1% of old patients. This finding bias might partly be explained by the incomplete application of screening tools to detect delirium in our cohort. At that time a standardized screening method was lacking for diagnosing a delirium. Currently, all geriatric patients are screened for delirium and co-treated by geriatrics in our geriatric trauma centre.
Mortality
There was a trend towards increased mortality in the older group compared to the younger group, but the difference was not statistically significant. These results are in contrast to recent studies (11, 13, 23). However, these studies did not use matched-pair analysis.
With the significantly increased rate of complications and additional predisposing negative factors for survival one would expect a significantly higher mortality rate in this group. Possible reasons for this discrepancy may firstly be a higher rate of very early death in the older population, meaning that the most severely injured and vulnerable old patients do not even make it to the hospital or die in the resuscitation area and therefore are not included in our data set. On the other hand, the rate of death in the consecutive medical course following hospital treatment is also higher in the elderly than in younger groups, possibly pointing to a larger portion of deaths of geriatric patients short-time following discharge, which are not recorded in our study as well (13, 34, 35).
Furthermore, some of the matching criteria require critical discussion. Even though GCS, coagulopathy, BE and ISS are considered to be strong predictors for adverse outcome in trauma(29), elderly patients are presenting with more comorbidities, hence there might be a bias within the matching itself due to pre-existing conditions (20, 30–33). It is more likely to find a pre-existing decreased GCS in an older patient. The same may apply for the base excess. In contrast to a young patient a pathological base excess in an old patient can be the consequence of a chronic disease. Even the coagulopathy may result from pre-existing medication. All these factors may lead to matching of pairs with different severities of trauma resulting in the same ISS with consecutive differences in mortality. However, the results of the mortality rate amongst the older patients may also be considered very encouraging as it demonstrates the potential for recovery after severe injuries even in the older population.
The older patients overall stayed for a shorter time at the trauma unit than the patients in the younger group. This might be surprising, as they developed more post traumatic complications than their younger counterparts. But with older people more often living in (medical) facilities some of them can be discharged earlier and in less favourable physical states because they receive medical care at home. Likewise, early hospital-intern transfer to an acute geriatric rehabilitation clinic after the acute phase from the trauma unit, counts as discharge in the database.
Complications
We found a significantly higher rate of complications in the group of the older patients compared to the younger ones after matching. This is consistent with the results of other groups (13, 18, 34, 36). Providing trauma care to geriatric patients is particularly challenging as these patients present with more comorbidities and smaller physiological reserves rendering them more susceptible to develop complications(34, 37, 38), a clinical state that is defined as frailty(9, 39). A frail individual is more vulnerable to develop negative health related events when exposed to a stressor (17, 19, 39, 40). Frailty is not only found in the elderly but its rate increases exponentially with age (41).
Typical complications were found in the group of elderly patients. First, the higher rates of anaemia might be multifactorial and partly be caused by the fact that anaemia in general is a more common pre-existing state in the elderly population rising up to 40% due to underlying diseases (42). Second, we found elderly patients to have a significantly higher risk to develop an acute coronary syndrome, which matches the results of other groups even without the presence of trauma (43). The additional factors of anaemia, due to blood loss, and the physiological stress of trauma might even further increase that risk. Third, another complication mainly amongst the older polytrauma patients was pneumonia. Due to physiological changes, comorbidities and longer periods of immobilization in the elderly, they are generally more prone to pneumonia than their younger counterparts (38, 44–46).
Another explanation for the higher rate of complications in older patients can also be found in the possible lack of diagnosis at the time of admission(38). Older people are commonly admitted with a multitude of comorbidities requiring different types of medical treatment. Yet after a major trauma the medical history might not be available right at the point of admission, leading to pre-existing chronic diseases not being properly treated or to pharmaceutical interactions between the patient´s standard and administered emergency-medications further aggravating the patient´s physiological situation.