New Evidence on Substance Use Disorders and COVID-19 Susceptibility

Covid-19 virus
Courtesy of NIAID

As I wrote in April when the COVID-19 pandemic was an emerging health threat in the U.S., there is reason to be concerned that people with substance use disorders (SUDs) may be particularly vulnerable to COVID-19 and its most adverse health outcomes. At that point we had very little data to directly support that hypothesis, but we can now speak with greater confidence.

Two weeks ago in Molecular Psychiatry, my collaborators QuanQiu Wang, Rong Xu (both at Case Western Reserve University), David C Kaelber (The MetroHealth System, Cleveland, OH), and I published an analysis of electronic health record data from more than 73 million patients at 360 U.S. hospitals, of whom 7.5 million (10.3% of the sample) had an SUD and 12,030 had COVID-19. It was clear from our analysis that people with SUDs are indeed at higher risk of contracting and suffering worse consequences from COVID-19. This was especially true for African Americans.

People with SUDs were significantly overrepresented among those with COVID-19, making up 15.6% of the COVID-19 group versus just 10.3% of the total sample. Risk of COVID-19 was highest among those who had received a diagnosis of SUD within the past year. Those with a recent OUD diagnosis were 10.2 times more likely than those without a recent SUD diagnosis to have COVID-19, followed by recent diagnosis of tobacco use disorder (8.2 times more likely), alcohol use disorder (7.8 times), cocaine use disorder (6.5 times), and cannabis use disorder (5.3 times).

The 7.5 million patients in the sample who had ever had any SUD (lifetime SUD) were 1.5 times more likely than the rest to have a COVID-19 diagnosis. Those with an opioid use disorder (OUD) were 2.4 times more likely to have COVID-19 than those without, followed by people with cocaine use disorder (1.6 times), alcohol use disorder (1.4 times), and tobacco use disorder (smoking or vaping; 1.3 times).

Patients with lifetime SUD diagnoses also experienced more severe outcomes from COVID-19 than others, including hospitalization (41% versus 30%) and death (9.6% versus 6.6%). The disparity between African Americans and Caucasians was stark: 13 percent of African Americans in the sample with both lifetime SUD and COVID-19 died, versus 8.6 percent of Caucasians with both diagnoses.

The reasons for the increased risk of COVID-19 infection and adverse outcomes among people with SUDs are probably complex. First, many kinds of chronic substance use harm or weaken the body in ways that make people who use substances more vulnerable to infection. As I described recently in Annals of Internal Medicine, opioids compromise respiration. The slowing of breathing caused by opioids can lead to hypoxemia—reduced blood oxygen—which can harm the brain as well as compromise cardiac and pulmonary health. Behaviors associated with opioid use and certain other kinds of illicit drug use also raise the risk of contracting infectious disease of all kinds. Despite social distancing, people with drug addiction need to interact with other drug users or dealers, for example, in order to obtain drugs.

Our study also showed that tobacco use disorder (defined as nicotine dependence, without specification of the mode of administration) puts individuals at heightened risk for COVID-19. The lung damage caused by smoking is well known; research suggests vaping also compromises lung health. The link between smoking and vaping and COVID-19 is also supported by a recent analysis of the results of a survey of smoking-related behaviors and COVID-19 symptoms and diagnoses published in the Journal of Adolescent Health. Among 4,351 adolescents and young adults nationwide who were surveyed, those who had ever used e-cigarettes (but not traditional cigarettes) were five times more likely to report having COVID-19, and those who had ever used both e-cigarettes and traditional cigarettes were seven times more likely to report having COVID-19. (A possible confounding variable was that these groups were also more likely to get tested for COVID-19.)

Besides compromising health directly, substance use and addiction also affect health indirectly by impeding access to healthcare. Because of stigma, people with SUDs are often more reluctant to seek all kinds of medical treatment than other people, and when they do seek treatment, they may receive substandard care or even be rejected for care. These barriers make it more likely that people with SUDs who contract COVID-19 will not receive the best treatment or will delay seeking treatment, putting them at greater risk of adverse outcomes.

These impacts are greatest for African Americans. Although Blacks misuse opioids at similar rates to whites, the analysis we published last week found that even among patients with opioid use disorder, there was a disproportionate number of COVID-19 diagnoses among African Americans. As a result of social and economic disparities, African Americans have higher rates of the comorbidities that raise susceptibility to COVID-19, including hypertension, diabetes, cardiovascular diseases, and kidney diseases.

Given what we now know about SUDs and COVID-19 susceptibility, it is crucial for providers to screen patients who have or are suspected of having COVID-19 for SUDs and smoking/vaping history. This is especially true for African Americans, for whom SUD may confer special vulnerability for COVID-19 as a result of longstanding disparities in health and healthcare access. Patients with SUDs or potentially compromised lung health from smoking and vaping should be monitored closely to best prevent the most adverse complications of the virus. And addressing SUD should be part of any comprehensive public health approach to addressing COVID-19.

Dr. Nora Volkow, Director

Here I highlight important work being done at NIDA and other news related to the science of drug use and addiction.

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