Associations between self-harm and chronic disease among adolescents: A cohort study using statewide emergency department data from California

Introduction: We sought to understand the association between youthful self-harm and sub- sequent chronic disease-related healthcare utilization and whether self-harm reflects unique vulnerability in comparison with severe psychiatric disorders. Methods: We used a retrospective matched cohort design with statewide, all-payer, individually linked emergency department (ED) data from California, USA. Risk of future ED visits for common chronic conditions in adolescence (headaches, asthma, epilepsy, diabetes, and gastro- intestinal disorders, assessed using ICD-9 diagnoses) were compared between three adolescent study groups presenting to an ED in 2010: self-harm patients (n=5,484), patients with psy- chiatric complaints but no self-harm (n=14,235), and patients with other complaints (n=16,452). Cohort follow-up ended on Sept. 30, 2015. Analyses were adjusted for patients prior histories of ED utilization for chronic conditions as well as patient- and area-level socio- demographic characteristics. Results: Risk of subsequent ED visits was higher among self-harm patients compared to non- psychiatric control patients for subsequent epilepsy- (aRR=1.77, 95% CI [1.42, 2.21]). Risk of subsequent ED visits was higher among psychiatric patients compared to non-psychiatric control patients for subsequent headache- (aRR=1.31, 95% CI [1.21, 1.42]), and epilepsy-related problems (aRR=1.85, 95% CI [1.55, 2.21]). Self-harm patients were at higher risk than psy- chiatric patients for subsequent gastrointestinal disorder (aRR=1.76, 95% CI [1.03, 3.01]). Conclusions: Findings suggest that self-harm behavior and psychiatric disorders are associated with increased ED utilization for subsequent chronic disease-related ED utilization. Chronic disease among adolescent psychiatric patients should be attended to, potentially involving new models of clinical follow-up care.