The original dataset, with 7875 cases, was used for the missing value replacement method, because as mentioned previously, it is preferrable to include as many predictive variables as possible in the model so that the new replaced/imputed values are indeed best estimates. Once the dataset had the missing variables for age and alcohol screen result replaced, the dataset was then amended to only include participants greater than 16 years of age to meet the inclusion criteria. Once those cases were removed, the final dataset consisted of 4910 unique cases. The first aim of this study was to identify the prevalence of THC in a purposive sample of TBI patients. In this study, it was found that 27.7% of study participants tested negative for THC, and 6.2% of study participants had tested positive for THC on presentation to the emergency department. An overwhelmingly large percentage of the data was attributed as missing, 66% to be exact. This large percentage of missing data makes it difficult to have confidence in the 6% prevalence rate found in this study. National surveys on drug use and health have documented an increase in individual daily marijuana use over the last 5 years, with almost 22 million users each month in the United States . Federally, marijuana use remains illegal in the United States, however, in 2017, the year corresponding to the data of this study, 29 states had legalized marijuana for medical use,hydro trays and 8 states for recreational use. A recent study has found that marijuana use tends to be higher in states that have legalized its use compared to marijuana use in the United States overall .
As a result, it is difficult to have confidence in the low prevalence rate found in this study. Another important consideration to make regarding the large percentage of missing data is the scarcity of studies investigating marijuana use and prevalence in TBI patients. As noted earlier in the literature review, only one study, by Nguyen et al. , investigated the effects of THC presence on mortality in patients who had sustained a TBI, and they reported a prevalence rate of 18.4%. However, Nguyen’s et al. study involved a 3-year retrospective review of data obtained from a local hospital-based database, which can perhaps help explain their higher prevalence rate. The availability of a larger sample size because of 3 years’ worth of data may have contributed to that study’s higher prevalence rates. A recent publication has already noted areas of improvement necessary for the NTDB to improve data quality and completeness . It is important to note that the dataset used for this study reflects only one year worth of data, from 2017. At the start of this research study, the last dataset available for use was from 2017; datasets from 2018 and onward had not yet been released. Therefore, establishing previous prevalence rates for comparison, from the NTDB, could not be calculated because the presence of THC was never abstracted nor documented in earlier NTDB databases established before 2017. Finally, it is imperative to consider what happens at the bedside, or the clinical setting, when trying to understand why there is a large percentage of missing data when it comes to the presence of THC. When it comes to the care of the trauma patient, it is a common expectation amongst trauma centers, that a urine drug screen would be completed on every trauma patient presenting the emergency department. Despite this, drug screens are often either not obtained, not resulted, or not documented by the clinical team. At times, clinicians may simply forget to draw a screen and send it to the lab.
This commonly occurs in patients who do not receive a foley catheter, a practice that is now encouraged in hospitals. As a result, patients may take a while to urinate, often doing so in the absence of the trauma nurse, or later in another unit or when under the care of a non-trauma nurse who then simply forgets to collect the sample. At times, the sample may be collected, but the result was never documented in the medical record. All these clinical factors can also contribute to the missing data by simply not including it in the medical record, and ultimately not making it into the trauma registry itself. When examining the differences between the group of participants with THC and those without and the influence on TBI severity, it was noted the group of participants who tested positive for THC had worsened GCS scores compared to those who tested negative for THC on presentation to the emergency department. The findings were significant, indicating that individuals who were positive for THC had a worsened neurological status as evidenced by lower GCS scores than those who tested negative. This finding is different than findings reported in the study by Nguyen et al. , which examined the relationship between the presence of THC and mortality after TBI. Their study only focused on mortality after TBI and not TBI severity. Based on toxicology test results, participants who tested positive for THC had a significantly higher number of males. Additionally, participants in the group that tested negative for THC were significantly older than participants who tested positive. This is supported by the literature, which indicates that men are more likely than women to use marijuana, as well as almost all other types of drugs . Individuals 18-29 years of age were the largest group of marijuana uses in the US in 2019 . Marijuana use dropped among older age groups, with seniors the least likely to use marijuana . No differences were noted in Non-Hispanic versus Hispanic groups regarding marijuana use. Marijuana use was higher in the American Indian and Black participants when compared to all other race groups.
Participants who identified as ‘other’ had a greater proportion of testing negative compared to all other race groups. Marijuana use disorder was greatest among African Americans compared to other race/ethnicities . Marijuana policies are rapidly evolving in the United States, however, previous marijuana laws disproportionately targeted communities of color before legalization, and many policy makers argue that new policies are not being developed with the input of minority stakeholders. Biomedical research has also marginalized and underrepresented communities of color. There is an obligation on the part of researchers, especially in the context of trauma and marijuana use, to actively work toward improving equity in marijuana related research. The mean blood alcohol level for participants in the group that tested positive for marijuana was higher when compared to the group that tested negative. Though the difference was not statistically significant, it corroborates finding from the literature, that marijuana is the most used drug among individuals who drink. A study by Subbaraman and Kerr found that individuals who use both marijuana and alcohol tend to use them at the same time, and that the odds of drunk driving, social consequences and harms to self were doubled. Participants who had a history or presence of cancer were more likely to test positive for marijuana compared to those who did not have a history or presence of cancer. The difference was statistically significant. Studies examining the use of marijuana for the treatment and management of symptoms medical conditions such as cancer is growing rapidly. There is evidence suggesting that cannabis for medical use reduces chronic and neuropathic pain in cancer patients . These studies support the finding in this study that a larger proportion of patients who tested positive for marijuana had cancer documented as a comorbidity. Similarly,vertical grow system participants who had a substance abuse as a history or comorbid condition documented were more likely to test positive for THC when compared to those who did not have substance abuse as a comorbid condition. This finding too is supported in the literature, as marijuana use has been associated with concurrent use of other drugs . An important consideration needs to be made in the context of this finding; for the variable of presence of other drugs, 66% of the data was missing. Since there is a large percentage of missing data, results should be cautiously interpreted and not assumed to be valid at face value in the context of such a large percentage of missing data. Lastly, no differences were found between the two groups of participants who tested positive and those who tested negative for THC when looking at likelihood of being involved in a motor vehicle of motorcycle collision. This study indicated a significant relationship between GCS scores, sex, alcohol results, and history of substance abuse. There is a small positive correlation between age and GCS scores which suggest that increases in age were correlated with an increase in GCS scores. Conversely, there was an inverse relationship between alcohol screen results and GCS scores, where higher blood alcohol screen results were significantly associated with lower GCS scores, and ultimately, more serious TBIs. Lastly, age and alcohol were also correlated significantly, with higher alcohol levels in younger patients. These findings are supported by research studies that investigate the relationship between alcohol, age and TBI severity. In a recent study by Leijdesdorff et al. , it was found that TBI patients with high blood alcohol levels were predominantly male and were younger.
Furthermore, TBI patients with positive blood alcohol levels were found to have higher levels of disability and significantly poorer cognitive outcomes on discharge . While patients with a positive THC test had significantly lower GCS scores on admission when compared to patients who did not have THC, or were not known to have THC on admission to the ED. Once other variables, including age, presence of alcohol on admission, sex, presence of other drugs and comorbidities were considered, findings indicated that the presence of THC was indeed associated with lower GCS scores, hence worsened TBI severity, however, the findings were not statistically significant. Age, race, ethnicity, motor vehicle collisions, and motorcycle collisions were also not shown to be independent predictors of TBI severity. Conversely, sex, presence of alcohol on admission, presence of other drugs, and a history of substance abuse were identified as independent predictors of TBI severity. Being female was associated with higher GCS scores indicating a less severe TBI. Similar to findings in previous studies examining TBI and sex, 67% of the study sample were male, while 32.9% of the sample were female. Gender differences in TBI incidence have been well documented, with men more likely to engage in injury-prone work or high-risk dangerous behavior . Additionally, women are less likely to be involved in a physical altercation than men . Furthermore, gender differences, can influence clinical outcomes between men and women. Research studies have proposed that female steroid hormones may exert some neuroprotective effects through antiinflammatory and antioxidant processes and may therefore explain why women tend to have better cognitive and functional outcomes after a TBI when compared to men . As expected, this study showed that the presence of alcohol and drugs at the time of injury were independent predictors of lower GCS scores, or otherwise a moderate or more severe TBI. The TBI literature does provide evidence of a close relationship between substance abuse disorder and TBI . Large percentages of patients who have sustained a TBI have a history of alcohol abuse and drug use, up to 79% and 33% respectively . In another study by Andelic et al. found that 35% of TBI patients were under the influence of alcohol. In this study there was a large percentage of alcohol levels missing, therefore, data was imputed. If in the original data set values were consistently measured and recorded, then findings regarding alcohol presence at presentation would possibly be much higher. Nevertheless, with the imputed values only 23 unique cases did not have an alcohol result. This too, may bias the finding, but like other study findings, this study’s finding showed that when alcohol was present at the time of injury participants had a lower GCS score, hence a more severe TBI indicating a worsened neurological status at presentation. Likewise, patients who were positive for at least one substance/drug were also found to have lower GCS scores and worsened TBI severity.