Alcohol is the most used drug in the United States, with 50% of the population reported using alcohol in the past month according to the 2020 National Survey on Drug Use and Health [1]. Alcohol is also the most abused drug. Of the 138 million current alcohol users in the United States, 61 million reported binge drinking in the past month and 28 million, or 10% of the population, met criteria for alcohol use disorder (AUD) in the past year [1]. Alcohol use and abuse is associated with numerous detrimental physical and mental health effects [2], and between 2011 and 2015, excessive drinking was responsible for 261 deaths per day [3]. Harmful alcohol use is the third leading cause of preventable death in the United States [4]. In addition, alcohol abuse and its consequences are costly. In 2006, the estimated hospital costs for treatment of alcohol-related issues exceeded $5 billion, but the total estimated economic cost of excessive drinking exceeded $220 billion [5].

Alcohol abuse impacts individuals’ perception of the problem and ability to obtain treatment when needed. The vast majority of individuals with substance abuse disorder do not feel that they need treatment, with only 2.5% of people with substance abuse disorder perceiving a need for treatment [1]. In trauma patients, a formal discussion with their medical providers about their alcohol use, screening for alcohol abuse, and a discussion of how their alcohol use contributed to their injury has been shown to significantly decrease recidivism in these patients for traumatic injury associated with alcohol use [6,7]. The acuity and direct correlation of the two problems (alcohol use and their injury) has been hypothesized to be a “teachable moment” with greater chance of initiation of change [8].

Alcohol abuse that leads to an intensive care unit (ICU) admission is another opportunity for medical providers to use the life-threatening medical problem to help patients with AUD recognize the issue and may be an impetus for seeking treatment or behavioral change. In this study, we describe the patient population admitted to a tertiary referral center ICU serving a large, rural area, including risk factors associated with worse outcomes in patients with AUD and evaluating the effect of chemical dependency (CD) referral and evaluation.

We performed a retrospective review of patients admitted to an ICU in our Level 1 Trauma Center located in Northern Minnesota, in the upper Midwest of the United States serving a large rural area between January 1, 2017 and March 31, 2019. Patients with documented AUD (alcoholism, alcohol dependence, and alcohol abuse) were included in the study group. All patient’s charts were reviewed to ensure that they had an alcohol use history consistent with an AUD. Patients with only social alcohol use and those who opted out of research with the healthcare system were excluded. In addition, patient chart and ICU stays were reviewed, and any patient that was admitted to the ICU only for monitoring and who did not require intensive care of for least 48 hours was excluded. Intensive care was defined as a need for continuous intravenous medications requiring at least hourly titration by an ICU nurse, mechanical ventilation, or evidence of at least one ICU treated organ failure. This study was reviewed, monitored, and approved by the Institutional Review Board of Essentia Institute of Rural Health, Duluth, MN, USA (No. EH20653). Patient consent was waived for this study.

After the study cohort was identified and electronically abstracted, manual chart review was performed for all patients by the first author (KC). All patient demographics, including age, sex recorded at birth, self-identified race, marital status, and insurance type were recorded. Current or former use of tobacco or other drugs of abuse was collected, as well as if the patient was still drinking alcohol prior to admission. ICU and hospital data were recorded for all patients, including primary reason for admission, hospital and ICU length of stay, use of mechanical ventilation or non-invasive ventilation, and complications that occurred during the hospital stay. Complications were included in analysis as a composite variable of any complication during the hospital admission, as well as by individual complication type (alcohol withdrawal, infection, septic shock, organ failure, acute respiratory distress syndrome, thrombotic complications or bleeding complications). ICU type was defined not by the physical location, but by the primary intensivist team (medical critical team or surgical/trauma critical care team). All critical care physicians at our hospital are board certified in critical care. Trauma ICU and surgical ICU were defined as cared for by the surgical/trauma critical care team and then patients’ reason for admission. If admitted due to injury, the patient was classified as trauma ICU. If not injured, they were defined as surgical ICU. Manual chart review was performed of all in-patient documentation by the medical provider for documented discussion of alcohol-related CD evaluation and counseling regarding the health and quality of life benefits of alcohol cessation. If CD evaluation and counseling was documented as being performed, the chart was then reviewed for documentation of patient acceptance of further support, referrals, or a verbal willingness to quit. This provider-initiated CD counseling was performed once the patient was recovering from their critical illness and most occurred outside of the ICU. In-hospital and 1-year mortality, and 6-month post-discharge readmissions due to alcohol abuse or its complications were also documented.

Statistical analysis was performed using IBM SPSS version 26.0 (IBM Corp.). Descriptive analysis was performed for the cohort, as well as comparing outcome variables. Primary outcome variables were in-hospital mortality, 1-year post-discharge mortality, and 6-month post-discharge readmission. Variables were compared using chi-square tests for categorical variables, and Mann-Whitney U-tests for continuous, non-normally distributed variables. Binary logistic regression was used for multi-variate analysis, which controlled for patient age, sex, and any variables associated with the outcome variable in univariate regression analyses. P-values of less than 0.05 were considered statistically significant.

During the study period, 649 patients were admitted to our ICU with a diagnosis associated with AUD, which accounted for 8% of ICU admissions during the time period. Upon chart review, 122 patients were excluded as they did not require ICU care or had an ICU length of stay less than 48 hours, leaving 527 patients in our cohort (Figure 1). Patient demographics are described in Table 1. There was a wide age range, from 18 to 86 years. Median age was 56 years. Seventy percent of patients were male, and the majority were Caucasian, followed by American Indian/Alaska native, Black, and Asian/Native Hawaiian/Pacific islander. Over a one third of patients were from rural localities, 80% had two or more comorbidities, and 46% had liver failure or cirrhosis diagnosed prior to their admission. Even with the high number of patients with existing liver failure/cirrhosis, most patients (88%) were still drinking just prior to their admission. Of the 241 patients with liver failure/cirrhosis diagnosed prior to admission, 40% were still drinking.

The primary reason for admission varied as depicted in Figure 2. ICU care was performed in medical ICUs three-quarters of the time, followed by trauma then surgical ICU. The median ICU length of stay was 3 days, and the median hospital length of stay was 8 days. Most patients had at least one complication during their hospital stay (81%) (Figure 3). The most common complications were symptomatic alcohol withdrawal, infections, and bleeding. Compared to patients who did not have complications, patients with complications had significantly longer hospital stays (median: 9 days; interquartile range [IQR]: 5–14 vs. 4 days [2–7]) and ICU stays (median [IQR]: 4 days [2–7] vs. 2 days [2–3]). Approximately half of patients were discharged to home, followed by discharge to skilled nursing or acute rehab. Nine percent were discharged to inpatient mental health treatment and 12% of patients died during their hospital stay. In our cohort of ICU patients with severe AUD, almost one third died within a year of ICU admission based on available mortality data.

In this large, retrospective cohort study based in a predominately rural area of the Upper Midwest of the United States, we found that ICU admission in patients with alcohol abuse is common and associated with high morbidity and mortality. Alcohol abuse was identified in approximately 8% of ICU admissions at our hospital, which is similar to other studies, where alcohol abuse has been associated with 7%–34% of ICU admission [9-15]. Death during the index hospitalization was common, with 12% of patients dying during their hospital stay. This is similar to other studies that have evaluated alcohol dependence or abuse in ICU patients, which have reported mortality rates between 9%–30% [9-16]. In addition to high mortality in the hospital, we found these patients are at significant risk for death within a year of their admission. Specifically, 27% of the patients in our study died within a year of their admission. Christensen et al. reported that patients admitted to the ICU for issues related to alcohol abuse with any chronic complications had an increased risk of death that continued for 3 years after their initial admission [17]. Patients with alcoholic liver disease or cirrhosis were at the highest risk of death in our study, with a 23% in-hospital mortality rate and a 47% 1-year mortality rate. Mortality rates for patients with liver cirrhosis admitted to the ICU have ranged from 18%–100% in other studies [18-26]. While in-hospital mortality has been decreasing in more recent studies to rates more in line with our findings, long-term mortality rates remain high for patients with liver disease who require ICU admission [24,27,28]. Improvements in supportive care can resolve the acute illness, but long-term treatments for liver failure are still lacking. Liver dysfunction has been associated with impaired immune functioning, higher risk of bleeding, increased rates and worse outcomes in acute respiratory distress syndrome, and changes in metabolism and nutrition, which may account for the increased risk of mortality in these patients during and after acute illness [29-35].

Other risk factors for increased mortality in patients with AUD in our study included increased comorbidities at time of admission, need for mechanical ventilation, complications during the hospital stay, and need for blood transfusions. These findings are similar to other risk factors for death in all patients needing ICU care. In addition, we found that rural patients had significantly increased rates of in-hospital and 1-year mortality when compared to non-rural patients. Alcohol use in rural communities varies by region; however, current AUD has a lower prevalence in suburban areas (11%) compared to urban areas (14%) and is highest in rural areas (15%) [36]. Rural patients also tend to have higher rates of comorbidities and may have less access to preventive health care. In our study, while men accounted for the majority of patients, female sex was associated with an increased risk of death within a year of ICU admission.

We found that in addition to the high risk of mortality, patients with alcohol abuse admitted to the ICU required significant resource utilization. ICU and hospital lengths of stay were long, and 80% of patients had a complication during their hospital stay, and the vast majority required intubation during their stay, leading to high resource utilization in this patient group. Cervellione et al. [37] evaluated ICU resource utilization in patients with drug and alcohol abuse and reported similar hospital and ICU lengths of stay (median: hospital length of stay, 6 days; ICU length of stay, 3 days). They also found that the median cost per day was approximately $5,000 [34]. In addition to the resource utilization during the index admission, almost half of the patients in our study’s cohort were readmitted due to alcohol related issues in the 6 months after discharge. This number is likely an underestimate of the true rate of readmission, as patients may have presented to an outlying hospital whose data would not be available to this study.

Theoretically, most, if not all ICU admissions associated with AUD described in this study are preventable. If patients can decrease or cease alcohol use, overall population health could be significantly improved, and hospital costs could be decreased. In our study, we found that provider-led CD counseling and treatment discussions were associated with significant reductions in the rates of readmission and subsequent mortality. Using these high-risk situations as opportunities for employing motivational interviewing techniques to assist patients with changing their alcohol use, and hopefully setting up treatment options, has been described by other groups [8,38,39]. Importantly, in the present study, we found that even when patients did not voice acceptance of treatment support or a willingness to change, the CD counseling received was still associated with a decrease in 1-year mortality and a nonsignificant trend toward lower readmission rates. We feel that every opportunity for motivational change and active discussion with patients is important as even if they are not willing to change at the time of initial discussion, it may lay important groundwork for subsequent opportunities. Clark et al. [40] found that for patient with unhealthy alcohol use admitted to the ICU, the severity of acute illness was significantly associated with a readiness to change. Providers need to continue to support patients and advocate for healthy behavior modifications.

We found that there are opportunities for improving the rates of CD counseling offered by providers, possibly indicative of provider biases that led them to not provide counseling where it may have been valuable for patients. For example, older patients were less likely to have CD counseling during their stay. It is possible that providers felt that alcohol use in older patients is more deeply embedded and less likely to be amendable to habit change; however, this is a missed opportunity for intervention. In addition, patients admitted for treatment of sepsis or infection were less likely to have alcohol CD counseling. Patients admitted with alcohol intoxication, overdose, or withdrawal had high rates of CD counseling documented, including rates that were higher than in patients with AUD who did not have an AUD diagnosis directly attached to the admission etiology. This highlights the need for greater provider awareness and use of alcohol use and abuse screening for patients without alcohol-related admission diagnoses. In addition, active and standardized approaches to inpatient alcohol screening and counseling have been associated with improved rates of identifying patients at risk and improving outcomes [6,7]. This may be evidenced in our high rate of alcohol CD counseling in our trauma patients, where screening and brief interventions have been standardized and have high rates of use [41], particularly compared to other hospital admitting services. Currently, other ICU services do not have standard protocol for who should receive CD counselling, it is left to provider discretion. While the present study did not identify significant race or gender disparities, other studies have noted disparities in access to substance abuse treatment and screening based on race and gender, and providers should be cognizant of possible implicit biases [42]. Standardization of alcohol use screening and CD counseling across all care groups may help decrease these disparities.

Access to treatment for alcohol disorders remains an issue in the United States. In a 2020 national survey, numerous barriers to receiving treatment were identified [1]. The most common reason, reported by 19% of patients, was a lack of health care coverage and not being able to afford treatment [1]. Stigma regarding alcohol abuse may also be an ongoing hinderance to receiving alcohol use treatment when needed, with 12% reporting that they felt that receiving treatment for their alcohol issues would cause their neighbors or community members to have a negative opinion about them [1]. Medical providers discussing alcohol abuse and its consequences may help patients feel supported in requesting treatment and decrease stigma, assisting patients and families with viewing AUDs as treatable medical conditions, not individual failings or weaknesses.

We added to the literature on the high risks associated with alcohol abuse and critical illness through our focus in this study on a mainly rural population, as well as by limiting the retrospective review to those patients receiving ICU care for organ dysfunction. By removing patients who were only monitored in the ICU, we described those patients with critical illness associated with alcohol abuse and AUD. The study is limited by its single center design, as well as the use of retrospective data. Due to the limitations of the available data, we did not use an alcohol use screening tool to identify and quantify the severity of alcohol abuse and instead used diagnoses entered into the medical record to identify our cohort, which may have missed patients who qualified. We were also unable to grade alcohol abuse based on amount of alcohol used by patient report. In addition, mortality may have been higher, as our access to mortality data for the study cohort was limited to mortality data available in the medical record.

ICU patients with alcohol abuse and AUD continue to have high rates of in-hospital mortality, as well as ongoing risk of death in the year following index admission. These patients accounted for high ICU and hospital resource use and had high rates of readmissions. Provider-led CD counseling can be associated with significant improvements in patient outcomes, and ongoing efforts to increase rates of in-hospital alcohol use screening and interventions to provide treatment options are imperative.