Predictors of clinical severity in subjects attending the Emergency Department for substance use: a ten-year cross-sectional study

Objective: Substance-related referrals to the Emergency Department (ED) are rising. Multiple substance use is frequent, and psychiatric patients represent a high-risk population. Our study aimed at identifying risk factors for increased severity in ED attendances for substance use. Methods: We retrospectively evaluated consecutive patients attending the ED over ten years for substance-related problems, subdivided according to the triage code as having a life-threatening (LT), potentially life-threatening (P-LT), and non-life-threatening (N-LT) condition. Results: Substance/drug intake for deliberate self-harm was a risk factor for being classified as LT compared to both P-LT (OR = 6.357; p ≤ 0.001) and N-LT (OR = 28.19; p ≤ 0.001). Suicide attempts (OR = 4.435; p = 0.022) and multiple substance use (OR = 1.513; p = 0.009) resulted as risk factors for P-LT, compared to N-LT. Psychiatric diagnosis (OR = 1.942; p = 0.042) and multiple substance use (OR = 1.668; p = 0.047) were risk factors for being classified as LT rather than N-LT. Conclusions: In our sample, self-harming overdoses were the strongest risk factor for highest overall severity in a real-world setting. Psychiatric disorders and multiple substance use also increased the risk for greater severity at presentation. Substance use worsens patients' clinical picture and management, suggesting the need for consultation-liaison psychiatry services in emergency contexts and highlighting the role of EDs as key sites for identification and early intervention.