Factors associated with 30-day drug-related emergency department re-attendance among methamphetamine users: a territory-wide retrospective study in Hong Kong.

Background: Methamphetamine use is associated with frequent emergency department (ED) utilization, but factors associated with drug-related ED re-attendance are understudied. We aimed to characterize the pattern of 30-day drug-related ED re-attendance and evaluate the impact of the severity of acute toxicity and psychosocial interventions on such re-attendances.

Methods: We conducted a secondary analysis of 815 episodes of acute methamphetamine toxicity reported to the Hong Kong Poison Control Centre from all local public EDs between January 1, 2010, and December 31, 2019. We defined the index attendance as the first ED presentation related to methamphetamine within the study period, and drug-related ED re-attendance as a presentation directly related to the acute toxicities or sequelae of drug misuse. The primary outcome was 30-day drug-related ED re-attendance after hospital discharge. We performed univariate and multivariable Cox regression analyses to identify factors associated with the primary outcome.

Results: Within 30 days of hospital discharge, 131 (16.1%) patients re-attended the ED for drug-related problems, with 119 re-attendances (90.8%) involving methamphetamine and 76 (58.0%) for psychiatric complaints. In multivariable Cox regression analysis, failed previous detoxification treatment (HR 1.61, 95% CI 1.08-2.39, P = 0.019) and a history of drug-induced psychosis (hazard ratio [HR] 1.76, 95% confidence interval [CI] 1.16-2.68, P = 0.008) remained significantly associated with the primary outcome.

Conclusions: Drug-related ED re-attendance is common among methamphetamine users. Failed previous detoxification treatment and drug-induced psychosis are factors significantly associated with such re-attendances. The limited impact of the severity of acute toxicity and psychosocial interventions underscores the importance of primary prevention of methamphetamine misuse through public education and drug-control policy, and early multidisciplinary interventions before progression to drug-induced psychosis.