Characteristics of COVID-19 and trauma patients
Among all of 9248 trauma patients, 222 cases were suspicious of having COVID-19 infection. Similar to previous reports, fever, cough and fatigue were the most common symptoms in our study (39 %, 13 %, 13%, respectively) [10, 12, 13, 14].
Sixty-four confirmed cases showed a history of exposure to suspicious and symptomatic people at a higher rate compared to the 158 COVID-19-negative cases, which was statistically significant. (12.5 % to 3.2 %. p.Value = 0.012). This could lead us to be more cautious about approaching a patient with a history of exposure by not only providing more personal protective equipment for medical staff, but also taking immediate actions toward the isolation of these patients from other unsuspicious ones.
The most prevalent comorbidities among our studied patients were hypertension, diabetes mellitus and cardiovascular disease, similar to the previous reports [13, 15, 16].
We observed different age and injury patterns compared to the other studies in COVID-19 pandemic reporting the mean age of 67 years or older [10, 15, 16], and demonstrating low energy trauma as the most common mechanism of trauma [12, 17, 18]. Mean age of the patients in our study was 42.5 and 80 % of them were men, most were the victims of motor vehicle accidents (MVA) (72.7%). Besides, One study from Iran showed the mean age of the studied patients was 38.6, and high energy trauma was the main cause (8 patients out of 13) . Noteworthy, it could be concluded that despite government legislation of lockdown measures, strict traffic laws, and self-isolation at home, the MVA still has a devastating impact and the utmost role, giving rise to traumatic injury to the patients in Iran during the COVID-19 pandemic.
Among 64 confirmed cases, 33 showed orthopedic injuries, mostly comprised of the pelvis and acetabulum, clavicle, and pertrochanteric fractures (10, 7, and 6 patients, respectively). Among the patients with orthopedic injuries, 24 (72.7%) ones were the victim of MVA and 9 patients were injured due to falling down. The most common orthopedic injury in MVA and falling down subgroups were pelvic fractures and pertrochanteric fractures respectively.One systematic review on 44 COVID-19 positive cases with concomitant fractures, showed 29 patients with proximal femoral fractures, eight patients with spine fractures, and seven patients with limb bone fractures . In our study, 23 (69 %) out of 33 COVID-19 positive cases with concomitant orthopedic injury were managed surgically in line with the result of the aforementioned review that 29 patients (68 %) out of 44 patients underwent surgeries .
The outcome of COVID-19 and Trauma patients: ICU admission and hospital associated mortality
111 patients (50%) were admitted to the intensive care unit (ICU). This proportion remained constant among both COVID-19 negative and positive groups. One study of 82 COVID-19 positive versus 340 COVID-19 negative patients with concomitant hip fracture showed 9.8 % (8 patients) ICU admission in COVID-19 positive case compared to 0.9 % (3 patients) in COVID-19 negative ones, not presenting poor prognostic factors associated with more ICU admission . We observed no significant association with any baseline and prognostic factors with more ICU admission. While, a study of 34 COVID-19 patients, who had been operated, with an ICU admission proportion similar to our study (44%), stated that patients with comorbidities such as HTN and CVD, older age and the more complicated surgery have increased risk for admitting to the ICU . Of note, the ICU admission rate among COVID-19 patients without surgery is documented at 26 % in the literature . While the proposed reason for the mentioned results of previous reports could be that any surgical procedure brings about immune system compromise and jeopardize multi-organ functions resulting in the need for more ICU care, it should be taken into account that our surgical procedures were performed after ICU admission of the trauma patients. One explanation for the observed nonsignificant effect of associated comorbidities on the rate of ICU admission among our patients, may be rooted in the lower mean of their age compared with the aforementioned studies.
11.7 % (26 patients) of 222 patients were expired during hospitalization. The hospital-associated mortality rate of the COVID-19 positive cases with concomitant orthopedic trauma was 15.6 % (10 patients) which was in contrast to previous reports by Jain (36.3 %), Kayani (30.5 %), and Maniscalco (43 %) [10, 16, 20]. The most logical explanation could be the younger population of our study (mean age: 42) comparing to the mentioned studies. One study on 34 COVID-19 patients who underwent surgery with closer age distribution (median age: 55) to ours, showed a 20.5 % mortality rate . Meanwhile, it should be mentioned that case fatality rate of COVID-19 patients without surgery is 2.3 % . After a multivariate analysis of risk factors association with the mortality rate in the suspicious COVID-19 patients with trauma, it was determined that older age, COVID-19 infection, and surgical procedure are poor prognostic factors. However, Kayani et al. showed cigarette smoking and multiple comorbidities, and Lei et al. proposed more complicated surgeries and medical comorbidities as detrimental factors associated with more mortality rate in their study population [10, 13]. One of the most important findings of our study was that the presence of COVID-19 showed significant association with more mortality rate among trauma patients, which was similar to Kayani's report .
Strengths and limitations
We conducted a retrospective cohort study with a medium-sized sample of suspicious COVID-19 and trauma patients in a center with a high volume of incoming trauma patients from south of Iran, which evaluated 9248 trauma cases in a six months pandemic period. This large-scale referred patients to our hospital is an efficient representative of the Iranian people's profile regarding COVID-19 status during the pandemic. The other strength of our study could be using two confirming tests (HRCT and PCR) to increase more diagnostic accuracy and sensitivity.
One of the limitations was that asymptomatic carriers of COVID-19 disease were not investigated due to the lack of enough available PCR kits. Meanwhile, the incubation period of COVID-19 infection is stated to be 14 days, and trauma patients need to be managed urgently and any delay in surgical treatment may accelerate or exacerbate their current condition and leading to the poor functional outcomes [14, 22]. The other limitation was that any developing signs and symptoms in suspicious cases after their hospital course were not assessed.
During the COVID-19 pandemic, medical health care and hospital resources should be utilized wisely and optimally to reduce devastating morbidities and mortalities. The vast majority of trauma patients in Iran are victims of motor vehicle accidents and are in need of urgent medical and surgical interventions. Providing resourceful information about the epidemiological and clinical characteristics of trauma patients with COVID-19 would contribute to the well-organized decisions and systematic approach to the issues in pandemic condition.