Increased Mortality Risk in Patients with Illicit Substance Use and COVID-19: Analysis of a Large Brazilian Sample.

Abstract

Background: Illicit substance use (ISU) may be a potential predisposing factor for severe COVID-19 outcomes.

Objective: To conduct a propensity score-matching analysis to assess and compare the mortality rate of individuals who reported ISU among a sizable cohort of hospitalized COVID-19 patients in Brazil.

Methods: This population-based retrospective cohort study analyzed a nationwide Brazilian database of patients hospitalized for COVID-19. Eligible patients were aged >18 years and tested positive for SARS-CoV-2 infection. The primary exposure of interest was ISU, defined as substances prohibited under Brazilian law, primarily marijuana, cocaine, and crack. Statistical analysis was performed using t-tests, chi-square tests, the Propensity Score Matching (PSM) technique to create a balanced comparison group, and the McNemar test for paired samples to assess mortality risk among patients with ISU.

Results: In a cohort of 2,124,285 patients, 1,845 had ISU. The mortality rate in the ISU group was slightly higher than that in the non-ISU group (33% vs. 32%). After PSM, we found a higher odds ratio for death in patients with ISU (OR 2.18; 95% CI 1.85-2.57; p < 0.001).

Conclusion: Our study highlights a significant association between ISU and an increased mortality risk in COVID-19 patients.