Association of substance use with outcomes in mildly ill COVID-19 outpatients.

Background: Smoking, alcohol use, and non-prescription drug use are associated with worsened COVID-19 outcomes in hospitalized patients. Whether there is an association between substance use and outcomes in patients with COVID-19 who visited the Emergency Department (ED) but did not require hospitalization has not been well established. We investigated whether smoking, alcohol, and non-prescription drug use were associated with worsened COVID-19 outcomes among such patients presenting to the ED.

Methods: We conducted a secondary analysis of a clinical trial which sought to determine the effect of early convalescent plasma administration in patients presenting to the ED within 7 days of onset of mild COVID-19 symptoms. The study recruited 511 participants who were aged 50 years or older or had one or more risk factors for severe COVID-19. The primary outcome was disease progression within 15 days after randomization, which was defined as a composite of hospital admission for any reason, seeking emergency or urgent care, or death without hospitalization. Secondary outcomes included: no hospitalization within 30 days post-randomization, symptom worsening on the 5-category COVID-19 outpatient ordinal scale within 15 days post-randomization, and all-cause mortality. Substance use was categorized into either use or never use based on participant self-report. Logistic regression models were used to determine the association between substance use and outcomes.

Results: The mean age of the 511 patients enrolled was 52 years and the majority were females (274, 54%). Approximately 213 (42%) were non-Hispanic Whites, 156 (30%) Hispanics, 100 (20%) non-Hispanic Blacks, 18 (4%) non-Hispanic Asian, 8 (1%) American Indian Alaskan, and 16 (3%) unknown race. Tobacco 152 (30%) was the most common substance use reported. Alcohol use 36 (7%) and non-prescription drug use 33 (6%) were less common. Tobacco use and non-prescription drug use were associated with an increased risk for meeting the primary outcome ((tobacco: adjusted odds ratio [aOR] =2.08; 95% confidence interval [CI]: 1.37-3.15) and (drug: aOR =2.41; 95%CI: 1.17-5.00)) and increased risk for symptom worsening on the 5-category COVID-19 outpatient scale ((tobacco: aOR = 1.62; 95%CI: 1.09-2.42) and (drug: aOR = 2.32 95% CI: 1.10-4.87)) compared to non-use after adjusting for age, sex, plasma administration, and comorbidity.

Conclusion: Tobacco and non-prescription drug use but not alcohol use were associated with worsened COVID-19 outcomes in patients who did not require hospitalization on their initial presentation. Future studies should determine the quantity, duration, and type of drug/tobacco use that may worsen COVID-19.