Effects of Social Distancing on the Incidence of Traumatic Injuries

INTRODUCTION

The first case of SARS-CoV-2 in Louisiana was confirmed on March 9, 2020. By the end of April, confirmed cases state-wide rose to 27,286 with 6,365 in Orleans Parish, home to the city of New Orleans.¹ In response to the rising number of cases, mandatory state and city orders were put into effect on March 17, banning gatherings of more than 50 people and closing bars, casinos, theaters, and dine-in restaurants.

Social distancing is a nonpharmacological public health tool that can be used to slow the spread of infection diseases, especially when community transmission has already occurred and close contacts of infected patients are difficult or too numerous to trace. This technique is particularly effective in controlling pathogens that are spread via respiratory droplets, such as SARS-CoV-2, and thus require close contact for transmission.² Previous studies have demonstrated the efficacy of social distancing interventions in reducing the spread of infections during pandemics.^3–5 The CDC has also suggested the implementation of social distancing strategies to slow the spread of SARS-CoV-2.⁶

These social distancing recommendations and stay home orders may have other unintended effects on community health beyond blunting the spread of SARS-CoV-2. Here, we analyze the effect of the March 17 social distancing order on the number of patients admitted with traumatic injuries to our level 1 trauma center in New Orleans to assess a possible impact on rates of traumatic injury.

MATERIALS AND METHODS

Research approval was granted by the Tulane University Institutional Review Board and approval was obtained from University Medical Center. This is a retrospective analysis of trauma patients admitted to a level 1 trauma center from January 2019 through April 2020. All adult patients who met trauma criteria were included in our counts including trauma activations, trauma transfers, and admitted trauma patients.

Trauma patient counts were obtained using daily snapshot reports received from the institutional trauma registrar, which included the daily number of trauma patients for 2019 and 2020. We further divided 2020 into pre- and post-social distancing measures, which went into effect in New Orleans on March 17. Patients were grouped by date of injury (before vs after social distancing) and further stratified by mechanism of injury (blunt, penetrating, other). “Other” injuries were composed of thermal injuries and those that did not meet registry criteria. We then compared median daily and mean weekly counts of trauma patients for each group. Patient demographics and mechanism of injury were gathered from our institutional trauma registry database.

Data was analyzed using Stata version 14.2 (College Station, TX). The numbers of trauma patients before and after social distancing were compared using the independent samples t-test or the Mann–Whitney U test. Shapiro–Wilk and Levene’s tests were used to assess normality and variances, respectively. Nonparametric distributions are presented as median (IQR), normal distributions are presented as mean (standard deviation, median, [IQR]), unless otherwise noted. Differences were considered significant when a two-sided p value < 0.05.

RESULTS

Of the 1,309 adult trauma patients who presented to our hospital between January 1 and April 28, 2020, approximately 64% suffered blunt trauma (n = 837) and 22% suffered penetrating injuries (n = 290). Subjects were primarily male (n = 907, 76.4%), with a median (IQR) age of 38 (26–55) (Table 1). There was no significant difference in age before social distancing (median = 38; IQR [26–55]) and after social distancing (36 [25–52]). There was no difference in the racial or ethnic composition when comparing pre- and post-social distancing groups.

There was no significant difference in the number of weekly penetrating injuries before and after social distancing guidelines were put into effect (17.0 vs 17.1). Prior to March 17, there was an average of 56.6 (standard deviation = 7.7) weekly blunt injuries compared to 35.7 (7.9) after social distancing, representing a significant decrease in blunt injuries (p < 0.01).

In 2019, the number of daily trauma patients followed a nonparametric distribution with a median of 12 (IQR = 9–15), and the weekly number of trauma patients was normally distributed with a mean of 84.2 (standard deviation = 12.7, median = 83.5, IQR = [72.5–93]). Similarly, in 2020 prior to March 17, there was a daily median of 12 (9–15) trauma patients and a weekly median of 86.1 trauma patients (10.2, 84, [77–96]). In the 6 weeks after the March 17 social distancing order, there was a daily median of 8.5 (5–11) trauma patients and a weekly mean of 60.3 trauma patients (9.3, 63, [54–67]) (Figs 1 and 2).

There was no significant difference between the median daily or mean weekly number of trauma patients when comparing 2019 to 2020 prior to March 17 (12 vs 12; 84.2 vs 86.1, respectively) (Fig. 3). When comparing daily admissions in 2020 before and after March 17, there was a significant reduction in the median daily number of trauma patients (12 vs 8.5; p < 0.0001) after the social distancing order was put into place (Fig. 4). Additionally, there was a significant decrease in the mean number of weekly trauma patients before and after March 17 (86.1 vs 60.3; p < 0.0001). When comparing the weeks following the social distancing orders to 2019, the daily median number of trauma patients was significantly lower (8.5 vs 12; p < 0.0001). Similarly, the mean number of weekly patients significantly differed when comparing social distancing 2020 to 2019 (60.3 vs 84.2; p < 0.0001).

DISCUSSION

There was no significant difference between the number of daily and weekly trauma patients between 2019 and 2020 prior to social distancing. The introduction of social distancing orders on March 17, 2020, resulted in a significant decline in the number of both daily and weekly trauma patients compared to the early months of 2020. There was a significant decline in the total number of blunt trauma patients; however, the total number of penetrating trauma patients remained unchanged.

The observed reduction in patients after March 17 might be a result of high-risk patients avoiding the hospital due to fear of contact with SARS-CoV-2; however, the nature of traumatic injuries represented in this study requires emergent evaluation and treatment. Thus, we believe that the count data reflect a true decrease in traumatic injury and not a reduction in reporting.

Social distancing and stay home orders may reduce injuries due to mechanisms that typically occur outside of one’s home, while injuries that occur at home may be less affected by these orders. Interestingly, there was no reduction in the mean number of weekly penetrating injuries before and after social distancing. Most of the reduction of traumatic injuries can be attributed to a decrease in the weekly incidence of blunt trauma. It is unclear if the reduction of blunt injuries is a direct result of fewer motor vehicle accidents and minor assaults, or if there are other intermediate consequences of social distancing that ultimately caused the observed reduction. Future analysis comparing specific mechanisms of injury will further elucidate this effect.

While our data show that there has been a reduction in traumatic injuries, it is unclear how criminal activity has played a role in this reduction. A previous study has demonstrated an increase in violent crime during economic hardship.⁷ Interestingly, however, despite the severe economic impacts of social distancing, national data have actually shown a decrease in crime across major cities including Chicago, Detroit, Los Angeles, and New York.^8,9 Similar studies to ours, performed in these larger cities, would help determine if there is a correlation between crime and traumatic injury in the setting of social distancing.

CONCLUSION

The March 17 social distancing mandate had a significant effect of lowering the number of blunt trauma patients at our level 1 trauma center. This observed decrease could be caused by multiple factors, including decreases in accidents related to social gatherings or violent crimes in the area. Additional data will be helpful to determine the full effect of social distancing recommendations and stay home orders on traumatic injuries. Given the short amount of time since the implementation of these measures, further study of the ongoing situation will be vital to fully understanding the impact on our communities’ overall health. Further investigation will be needed to understand the entire implications of these findings and determine if the reduction in traumatic injury is a temporary or sustained effect of social distancing.

REFERENCES

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