Our results suggest that patients who had previous inpatient admissions, a SUD other than OUD, and/or self-identify as male have a higher risk of presenting to the ED post-discharge and may benefit from more intensive follow-up. Larger studies involving multiple sites are required to validate the generalizability of our findings. Findings from our study can be used to guide future studies examining post-discharge programs in patients with SUDs with and without comorbid mental disorders.