Authors: Hye Young Choi, Dylan Rose Balter, Lamia Y. Haque
Categories: Article, alcohol use disorder, prevalence, epidemiology, disease burden, healthcare utilization, healthcare costs, health disparities
Source: Clinics in liver disease
Authors: Hye Young Choi, Dylan Rose Balter, Lamia Y. Haque
Alcohol use disorder (AUD) stands as one of the most frequently diagnosed substance use disorders (SUD) in the U.S., impacting around 10% of individuals aged 12 or above, or approximately 29.5 million people. It is causally linked to over 60 diseases and accounts for half of all morbidity and mortality related to alcohol use.^1^ Beyond its significant health implications, AUD also bears a substantial economic burden of $249 billion annually, and associated gaps in prevalence, screening, and treatment rates perpetuate social inequality.
AUD is defined by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) as a pattern of alcohol use leading to behavioral, psychosocial, and physical impairment or distress.^2^ Since 2013, AUD has subsumed two previously separate diagnoses including “alcohol abuse” and “alcohol dependence,” and can be specified as mild, moderate, or severe AUD based on the number of specific DSM-5 criteria present.^2^
Of note, AUD is a chronic medical condition based on past-year symptoms whereas “excessive alcohol use,” “heavy alcohol use,” “binge drinking” and other forms of at-risk alcohol use are defined based on the quantity of alcohol consumption, and all fall under the category of “unhealthy alcohol use” along with AUD.^3^ Specifically, excessive alcohol use binge drinking, defined as having ≥4 drinks on one occasion for women and ≥5 drinks for men or as a level of alcohol intake that leads to a blood alcohol concentration of ≥0.08%; heavy alcohol use, defined as having ≥4 drinks per day or ≥8 drinks per week for women and ≥5 drinks per day or ≥15 drinks per week for men; underage drinking, defined as any alcohol use by individuals less than 21 years old; and pregnant drinking, defined as any alcohol use by pregnant individuals.^3^ A standard drink is defined as 14 grams of alcohol in the U.S., which amounts to 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of distilled spirits.^3^ At-risk alcohol use, including binge drinking and heavy alcohol use, may increase risk for AUD.^3^ However, the majority of those reporting excessive drinking do not meet criteria for AUD.^4^ While all forms of unhealthy alcohol use are of public health importance, the remainder of this article will primarily focus on the epidemiology of AUD and its healthcare burden.
Among all the substances included in the 2022 National Survey of Drug Use and Health (NSDUH) SUD measures, alcohol ranks first in use and misuse in the U.S., with over 29.5 million people or 10.5% of people aged 12 or older reporting a past year AUD.^5^ Within this group, 17 million have mild AUD, 6 million have moderate AUD, and 6.1 million have severe AUD.^6^ Overall, the prevalence of AUD surpasses the prevalence of all drug use disorders combined, including marijuana, cocaine, heroin, hallucinogens, inhalants, methamphetamine, or prescription drug use disorders, comprising 60.6% of all SUDs.^5^
Across the lifespan, there are roughly four times the number of adults aged 26 or older with AUD relative to young adults aged 18-25 and adolescents aged 12-17. However, young adults are proportionally at the greatest risk of AUD, with over 5.7 million or 16.4 percent of the age group reporting a past year diagnosis. In comparison, roughly 23.1 million or 10.4 percent of adults aged 26 or older and less than 753,000 or 2.9 percent of adolescents aged 12-17 have AUD.
While adolescents comprise a small fraction of those with AUD and underage alcohol use has been declining by 50-70% since 2002, high-risk adolescents may be important targets for prevention, as 15% of all lifetime AUD cases are known to develop before age 18.^7,8^ Indeed, earlier age at first drink of alcohol is associated with increased risk of developing AUD and youth are particularly vulnerable to other forms of unhealthy alcohol use, particularly binge drinking.^9,10^ According to the NSDUH from 2022, among 5.8 million people aged 12-20 who reported past-month drinking, more than half, or 3.2 million people, reported binge drinking.^7^ In addition to elevated risk for developing AUD in adulthood, binge drinking is associated with additional adverse outcomes such as suicide, substance use, and risky sexual behaviors.^10^
By gender, AUD has consistently predominated among males compared with females. Yearly NSDUH estimates show males continue to report higher rates of AUD than females, with 17.4 million or 12.6% of male respondents reporting AUD versus 12.2 million or 8.5% of female respondents in 2022. The prevalence of AUD increased for both males and females at a similar rate between 2019 to 2021, consistent with reports of increased alcohol consumption and disruptions in AUD treatment during the COVID-19 pandemic.^11,12^ In the most recent NSDUH estimates from 2022, females returned to pre-pandemic levels of prevalence while males demonstrated a constant rate of increase (Figure 1). While men comprise the majority of individuals with AUD, a review of 51 studies published between March 2020 and July 2022 found cisgender women suffered higher rates of alcohol use and alcohol-related harms than cisgender men.^13^
Among gender diverse people, comprehensive epidemiology of AUD is lacking, as annual NSDUH surveys do not include gender categories beyond male and female. However, existing literature suggests that on average, gender diverse individuals may suffer from higher rates of AUD. In the largest national cross-sectional study of SUD diagnoses among trans (n=15,637) and cis-gender (n=46,911) individuals, transgender participants had significantly higher rates of AUD than their cisgender counterparts across all age groups and geographic regions.^15^ Similarly, a retrospective cohort study of gender diverse (n=293) and cis (n=1698) patients at a single site from 2013 to 2021 revealed a significantly higher proportion of AUD diagnoses among gender diverse patients.^16^
For lesbian, gay, and bisexual (LGB) populations, NSDUH data spans from 2015 to 2022. Since 2015, LGB adults have reported higher rates of AUD than their heterosexual counterparts across all age strata in each year. However, similar to heterosexual individuals, LGB young adults aged 18-25 were at greatest risk for AUD, with over 1.5 million or 20 percent reporting a past year AUD in 2022.^17^ This period of heightened risk has been estimated to decrease after age 28 in LGB adults versus age 23 in heterosexual adults.^18^
One of the prevailing theories for heightened risk of AUD among sexual and gender minorities (SGM) includes the minority stress theory, which states stress and stigma associated with sexual orientation and gender identity leads to adverse health outcomes. Numerous insults including internalized stigma, discrimination, abuse, violence, and victimization have been linked to increased odds of excessive alcohol use, AUD, and alcohol-related consequences among LGBTQ people.^19^
Across race and ethnicity categories specified in the NSDUH, American Indians and Alaska Natives (AIANs) had the highest proportion of AUD with 280,000 people or 15.9 percent of the population reporting a past year diagnosis in 2021. In 2022, the proportion of AIANs with AUD decreased to 10.5 percent, a rate comparable to other racial and ethnic groups, with the exception of Asians who had an AUD prevalence of 5.6 percent (Figure 2). NSDUH data shows Asians are significantly less likely than all other racial and ethnic groups to have an AUD. However, prevalence of AUD varies widely upon disaggregation by nativity, in which Korean Americans (13.1%) demonstrate highest prevalence of AUD.^20^ Regardless of race or ethnicity, minoritized groups exhibit a dose-dependent association between frequency of discriminatory experiences and severity of AUD.^21^
Heritability of AUD varies between 12 to 50% depending on methodology, with recent twin-studies yielding the highest proportions of variance explained by genes.^22^ Large-effect alleles associated with increased risk of AUD include variants of genes responsible for alcohol metabolism such as ADH and ALDH. However, AUD traits are mostly explained by thousands of small-effect alleles, which are under-researched compared to the polygenicity of less severe alcohol use behaviors.^23^ While ongoing genome and epigenome wide association studies, identification of single-nucleotide polymorphisms (SNPs), and aggregation of polygenic risk scores continue to elucidate biological risk factors and potential pharmacological interventions for AUD, the environment and gene-environment interactions constitute key modifiable contributors of AUD risk.
Socioeconomic status (SES) is measured in NSDUH primarily through educational attainment, poverty level, and employment status. In 2022, those with some college or an associate’s degree reported the highest proportion of AUD at 12.4%, followed by college graduates at 11.6%, high school graduates at 10.1% and those with less than a high school education at 9.5%. Among three poverty strata, the greatest proportion of AUD was observed among those over 200% below the federal poverty level (FPL) at 10.8%. Those less than 100% below the FPL had AUD rates of 10.5%, and those within 100-199% of the FPL had AUD rates of 9.4%. AUD prevalence also varies by employment status, with unemployed individuals having the highest proportion at 15.5%, full-time employees at 14.1%, part-time employees at 12.3%, and people not in the labor force at 6.8%. NSDUH data does not point to an obvious relationship between SES and prevalence of AUD. Indeed, studies show people with higher SES consume similar or greater amounts of alcohol compared to people with lower SES, but the latter group suffers a disproportionate burden of negative alcohol-related consequences.^24^ This phenomenon, also known as the Alcohol Harm Paradox, has been observed internationally across multiple measures of SES since 1980, but its causal factors beyond individual risk behaviors remain understudied.^25^
Finally, in terms of health insurance status, individuals without coverage exhibited the highest proportion of AUD at 13.1%, surpassing the rates among privately insured individuals at 10.6%, Medicaid enrollees at 9.9%, and others (such as Medicare and military personnel) at 7.3%. Recent Kaiser Family Foundation statistics show the uninsured population is predominantly young adults, individuals with lower SES, AIANs, and non-U.S. citizens.^26^ Notably, this demographic aligns closely with the aforementioned populations that are disproportionately impacted by AUD, and these social determinants may contribute to worse AUD-related consequences.
Psychiatric conditions as well as other SUDs and medical illnesses frequently co-occur with AUD. NSDUH data shows among those with AUD, 42.2% had a mental illness in the past year and 37% had a comorbid SUD.^14^ In the Epidemiological Catchment Area Study (ECA, 1980-1985), one of the most extensive national investigations of the prevalence of mental illnesses, those with AUD exhibited a wide distribution of comorbid mental illnesses. Among them, antisocial personality disorder was the most prevalent at 14.3%, followed by any affective disorder at 13.4%, and schizophrenia at 3.8%.^27^ Globally, the longitudinal association between AUD and psychiatric comorbidity based on pooled estimates from meta-analyses ranged from 2.00 to 2.09 for major depressive disorder, 1.35 to 1.74 for attention-deficit hyperactivity disorder, 1.5 to 1.61 for anxiety disorder, 0.7 to 5.43 for post-traumatic stress disorder, and 1.5 to 1.6 for psychotic experiences.^28^
The National Epidemiologic Survey on Alcohol and Related Conditions (NESARC III, 2012-2013) revealed that adults with AUD had 3.3 times the odds of another SUD, 1.9 times the odds of borderline personality disorder, 1.6 times the odds of antisocial personality disorder, 1.3 times the odds of any anxiety disorder, and 1.2 times the odds of major depressive disorder.^27^ Based on NESARC II and III data, increased severity of AUD also correlated with more intense manifestations of psychopathology.^29^ Furthermore, alcohol use is known to independently increase risk for suicide, which is further pronounced with added psychiatric conditions. For instance, among individuals with comorbid AUD and borderline personality disorder, lifetime prevalence of suicide attempts is known to range from 21% to 42%.^30^ Finally, AUD is associated with a litany of medical conditions, some of which include cancers, cardiovascular disease, cognitive impairment, liver disease, pancreatic disease, infectious diseases, and traumatic injuries.^3^
Given the powerful association between SUDs and mental illnesses and increased risk for poorer outcomes with co-occurring disorders, researchers and clinicians have developed integrated treatment models to facilitate concurrent substance use and mental health interventions. Integrated care models in which AUD is treated along with co-occurring medical conditions have also shown promise. Integrated treatment is the best practice of care for people with co-occurring disorders and has been effective in diverse populations across different treatment settings.^31^
Excessive alcohol use also has a substantial impact on economic, societal, and healthcare costs. In 2010, the economic cost of unhealthy alcohol use in the U.S. totaled 8 billion, or the equivalent of 5.59 billion. Reasons for decreased productivity included compromised performance at work, lost productivity secondary to premature mortality, and greater rates of absenteeism. Additionally, this study found that binge drinking was the costliest drinking pattern, as it was associated with 40% of healthcare expenditures, 72.4% of decreased productivity costs, and 97.2% of other societal expenses.^33^ A similar study in North Carolina found that excessive alcohol consumption reached 9.72 billion, the state government paid 3.76 billion, and those who do not drink alcohol in North Carolina paid $1.53 billion.^34^ Thus, unhealthy alcohol use results in significant expenditures among not only federal and state governments, but also individuals.
In addition to staggering economic costs, excessive alcohol use has also contributed to significant societal costs. In 2021, alcohol was involved in 13,384 MVC deaths, which equates to 31% of all MVC fatalities.^35^ Furthermore, there is a significant interplay between alcohol and mental health emergencies. The CDC estimates that 21% of people who die by suicide have elevated blood alcohol concentrations and that approximately 25% of people who die by suicide have AUD.^35^
Excessive alcohol use has also substantially impacted the healthcare system and exacerbated healthcare expenditures. Among a population of 162 million individuals with employer-sponsored health insurance, the total annual healthcare cost associated with AUD was 14,918 and $4,823 for individuals with commercial and Medicaid insurance, respectively.^37^ The majority of these costs were due to heart disease, stroke, malignancies, and liver, gallbladder, and pancreas pathologies, all of which were secondary to excessive alcohol use.^37^
While heavy alcohol use has exacerbated healthcare expenditures at large, it has particularly impacted the ED setting. From 2006-2014, the ED saw a 47% increase in alcohol-associated visits.^38^ This increase equates to 210,000 additional ED visits, as well as a 272% rise in healthcare costs, from 15.3 billion. Notably, the rate of chronic alcohol-associated ED visits increased more than that of acute alcohol-associated visits (57.9% versus 40%). Additionally, there was a greater annual percent change in rates of alcohol-associated ED visits for females versus males (5.3% versus 4.0%).^38^ The ED has also experienced an increase in co-morbid alcohol and opioid-related events—in 2020, it is estimated that alcohol was involved in 7.1% of ED visits and 17.4% of fatalities attributable to opioid overdoses.^35^
Moreover, it is important to acknowledge the role of the COVID-19 pandemic in augmenting the economic, societal, and healthcare burden of AUD. A cross-sectional study of individuals during the COVID-19 pandemic found that 60% of individuals reported increased alcohol consumption compared to before the pandemic. Those who endorsed stress related to the pandemic reported an increase in both amount and frequency of drinking.^11^ As rates of alcohol consumption climbed during the COVID-19 pandemic, alcohol sales likewise increased. In 2020, alcohol sales rose by 2.9%, reflecting the greatest annual sales increase in 50 years.^39,40^ Such increases in both alcohol consumption and sales have further contributed to the societal burden of AUD. Data from the National Highway Traffic Safety Administration found a 14% increase in alcohol-involved traffic deaths in 2020, following years of decreasing fatality rates.^39,41^ The pandemic also perpetuated AUD’s healthcare burden, as ED visits for alcohol withdrawal increased by 34% in 2020 compared to 2019.^39,42^ Alcohol-related deaths at large also rose during the pandemic. From 1997 to 2017, the rate of deaths involving alcohol increased by an average of 2.2% per year. However, the COVID-19 pandemic rapidly accelerated these deaths rates, with an estimated increase of 25% from 2019 to 2020. While death rates increased across all age groups, individuals aged 25 to 44 experienced the largest increase.^43^ Alcohol consumption during this time was associated with male sex and recent unemployment due to the pandemic.^44^ Predictive models estimate that increases in alcohol use during the COVID-19 pandemic will result in a lower life expectancy, an additional 295,000 hospitalizations, and an associated cost of $5.4 billion during the next 5 years. ^44^ Thus, the pandemic reflects one important driver of increasing rates of alcohol use and disease burden. Although the relationship between the pandemic and alcohol use has not been fully elucidated, research suggests that heightened emotional and financial stress, increased availability of alcohol, unprecedented social isolation, and the large mental health toll of the pandemic have contributed to alcohol’s increasing healthcare burden.^11,45^
Beyond the COVID-19 pandemic, alcohol’s increasing healthcare burden is also a reflection of significant barriers to both AUD screening and treatment within our healthcare system. Despite the high rates of AUD-related morbidity and mortality, unhealthy alcohol use is frequently overlooked in healthcare settings, thereby leading to significant gaps in healthcare quality for individuals with AUD.^46^ Currently, the U.S. Preventive Services Taskforce (USPSTF) recommends that all adults aged 18 or older receive screening for unhealthy alcohol use in the primary care setting.^47,48^ Although individuals with AUD have high rates of healthcare engagement, studies have found that there has been poor implementation of validated screening for unhealthy alcohol use in the primary care setting. ^46,49^ This lack of formal screening may prevent appropriate subsequent interventions and treatment.^50^
For patients who screen positive for unhealthy alcohol use, USPSTF advises brief behavioral counseling interventions, which have been shown to decrease number of weekly drinks, the proportion of individuals surpassing recommended alcohol limits, and the proportion of individuals reporting an episode of heavy alcohol use.^47,48,51^ Notwithstanding the effectiveness of these interventions, data from the 2015-2019 NSDUH show that only 14.6% of people with AUD reported receiving a brief intervention in the past year.^49^ Qualitative studies of patients and providers have found that some barriers to screening and brief interventions in primary care include societal stigma, as well as lack of time, resources, and provider knowledge and training.^50,52,53^
Similarly, there are astonishingly low AUD treatment rates.^54^ Gold-standard treatment for AUD consists of a combination of evidence-based behavioral and pharmacotherapy modalities.^46^ NSDUH data from 2022 estimates that 7.6% of adults with AUD received treatment in the past year, and only 2.2% specifically received medication treatment for AUD in the past year.^54^ Several barriers may contribute to these low treatment rates, including limited healthcare training and emphasis on AUD treatment, as well as stigma attached to addiction and its treatment.^55-59^
Thus, AUD is associated with an increasing economic, societal, and healthcare burden. Though not exhaustive, some important drivers of this increasing burden include the COVID-19 pandemic as well as inadequate implementation of AUD screening and treatment within our healthcare system. It is critical to further explore such drivers and healthcare gaps to reduce future healthcare burden of AUD.
AUD is rising in prevalence and is one of the most common SUDs. Although AUD occurs more frequently in males, the prevalence among females and some minoritized populations, who are more likely to experience harmful effects and consequences of AUD, has risen. Despite the high morbidity, mortality, acute healthcare utilization, and societal cost associated with AUD, multiple barriers to AUD treatment exist along the cascade of AUD care, leading to insufficient screening and low levels of evidence-based treatment uptake. Innovative interventions that involve patient-centered multidisciplinary care models as well as public health and policy measures to prevent and treat AUD are needed.