COVID-19 progression in patients with and without using tobacco and other substances

Importance: The COVID-19 pandemic has not only ushered in severe environmental and economic challenges but has also led to the tragic loss of over 18.57 million lives worldwide, particularly impacting marginalized populations. Among these vulnerable groups, with a notably high prevalence in Iran, are individuals using substances. Objective: In this study, we sought the impact of substances on COVID-19 progression and compared it with the non-substance users. Design, Setting, and Participants: We studied 726 participants over different areas of Iran. 363 participants did report using any type of substances and 363 didn’t report any. COVID involvement was confirmed with PCR or CT scan.Main outcomes: We assessed different laboratory, clinical and admission days and mortality measurements. Results: Two groups were significantly different regarding age, gender, education, diabetes mellitus, asthma, and hypertension and didn’t differ regarding having cardiovascular disease, COPD, cancer, receiving chemotherapy and corticosteroids, kidney failure, and HIV. Case group suffered less severe illness (p<0.001). Logistic regression showed that the control group suffered 2.48 times more than the case group and this remained significant after controlling other factors. We couldn’t find any difference in mortality between the two groups. Case group hospitalization days were significantly shorter than the control group and Cox regression showed control group stayed at the hospital 24% more than the case group. However, when we controlled for other factors, we found no significant difference. Conclusion: Our findings underscore the imperative for conducting broader and more inclusive studies involving a diverse and sizable population of substance users, in order to effectively address their unique requirements.