Motorcyclists represent a quarter of road deaths in the world and a consistent part of all traffic victims. The number of motorcyclists suffering from road trauma is growing due to the rapid global expansion of the motorcycle market. The use of motorcycles is expanding also in older ages for enhanced mobility in heavy traffic urban areas. Some evidences suggest that age is generally an important predictor of mortality related to traumatic events(16,17). Our data demonstrate that older patients had an increased mortality for severe injuries. Head, chest, abdominal and pelvic injuries were all independent predictors of death; severe head injuries occurred more frequently in younger patients, while chest injuries were more commonly in older patients.
The relationship between age, severity of injuries and mortality following motorcycle trauma is still controversial (8,13). Mullin B. et al. demonstrated a relationship of inverse proportionality between age with risk of death and severe injuries in motorcyclists and car drivers(7). Increased age of motorcycle drivers has been strongly highlighted as a protective factor against fatal and non-fatal injuries deriving from motorcycle crashes (8,18), due to greater driving experience of older patients. Other studies showed that the elderly population have a higher risk of severe injuries and death(19). Underlying diseases in the older population would increase mortality for all types of trauma(20).
Some investigators suggest that drivers older than 40 years are 25% more prone to death after motorcycle injuries(12). Moreover, Richter et al. compared crash injury rates between older and younger road users, detecting a higher severity of the injuries and mortality rate in the older cohort(19).
In the present study the overall mortality rate was 4.9% for all motorcycle injuries, with the highest rate among the older group (≥ 55 years) and multivariate analysis confirmed that age is an independent predictor of death.
ASA score was available just for a bit more than a half of our sample. Due to this limitation, we couldn’t adjust our survival analysis for comorbidities. Anyway, because of the similar values of ISS and RTS between age groups, we can assume that older patients have a less tolerance for injuries of the same severity and increased ASA score may be a determinant of worsen outcome.
Talving P. et al. focused on the anatomical region injured, underlining that older patients, defined as greater than 55 years old, are significantly more likely to suffer severe head injuries, chest injuries, and spinal fractures(1). Dischinger et al. demonstrated that motorcyclists older than 40 years old show a significantly higher incidence of multiple thoracic injuries(21).
In our investigation, head injuries were the anatomic region most frequently injured overall. In the subset of severe injuries, chest injuries (33.1%) and head injuries (23.6%) were the most represented. By considering the group of critical injuries defined by an AIS 98’ ≥ 3, patients sustaining head trauma had a near 9-fold increased risk of death, whereas those sustaining chest and abdominal injuries had a 3.6-fold and a 2.4-fold increased mortality risk respectively. Older ages were associated with higher mortality and with a higher frequency of chest injuries with less severe head injuries. The thoracic cage of the elderly is more prone to costal and sternal fractures resulting in severe injuries to internal organs, which may be fatal. Given the atrophy of the brain in elderly patients, severe head injuries may evolve more slowly, as more blood is required to cause increased intracranial pressure. Younger patients have less atrophy and thus an even small bleed may progress to clinically significant increased intracranial pressure.
It is worth noting that on multivariate analysis, extremity injuries showed a correlation with a hypothetical improved prognosis (OR; 0,715; 95% CI: 0,574 – 0,89). This effect could be explained by the high number of extremity injuries, present in approximately 20% of the overall population, the majority of whom have survived.
In our sample mortality distributed in a bimodal fashion with a greater proportion of acute (within the first 48 hours) rather than early or late deaths confirming the findings of other authors in the current literature(22–26). The same trend was observed after stratifying the sample according to age, although in the older group the difference between acute and early/late mortality was less remarkable.
Many data available in the literature demonstrate improved survival of major trauma patients when treated in a dedicated trauma center showing a reduction in mortality rate, length of hospital stay and an improved physical function(27–30). MacKenzie et al. demonstrated besides that the overall risk of death for trauma injuries is significantly lower when care is provided in a trauma center(31). Although TRISS calculation has been largely questioned, it is still the most prominent method for trauma care benchmarking and the comparison between expected and observed survival is a good way to measure efficacy of care. Our data confirm the benefits of dedicated care at a trauma center and highlight an important survival benefit, more evident in severely injured and older patients. This underlines the importance of a dedicated team composed of physicians and nurses skilled in the management of trauma.
To our knowledge, our study represents the largest single center representation of major motorcycle injuries at a Level 1 trauma center in Europe with the review of 1725 patient’s data collected in a standardized registry during a 14-year period.
Nevertheless, some limitations exist in our study. A major concern could be raised considering that our data are not adequately weighted: especially in the older group, the influence of comorbidities on prognosis cannot be neglected. However, this type of data has started being gathered in the registry only since 2011, so our decision to not control for comorbidities is due to a lack of information in the database that eventually could alter the accuracy of the results. Finally, due to the non-homogeneous distribution of the sample among age groups (with most of the study population belonging to the young adults’ group), the opportunity to investigate the effect of every anatomical region injured in each age group was precluded. Moreover, it’s possible that a potential survivorship bias comparing young, adults and senior patients exists because in our database information about pre-hospital are unavailable.
due to an increase of the pre-hospital mortality
Moreover, the Trauma and Injury Severity Score (TRISS) was originally conceived in 1983 and in 2010, its coefficients were further revised(32,33). This scoring system is based on data obtained from north american trauma registries, the American College of Surgeons Committee on Trauma National Trauma Data Bank (NTDB) and the NTDB National Sample Project (NSP), with the latter reporting nearly 25% missing data. Despite being the most commonly used tool for benchmarking trauma outcomes, TRISS has important limitations that could account for such a wide difference in survival for patients sustaining critical injuries, especially those more than 55 years old(34,35).