BACKGROUND AND OBJECTIVE: Children and adolescents with attention-deficit/hyperactivity disorder (ADHD) are prone to sustaining trauma that requires emergency department (ED) admission. Methylphenidate (MPH) can reduce ADHD symptoms and may thus theoretically reduce the risk of trauma-related ED admission, but previous studies do not make this association clear. This study examines this association.METHODS: A total of 17 381 patients aged 6 to 19 years who received MPH prescriptions were identified by using the Clinical Data Analysis & Reporting System (2001. Using a self-controlled case series study design, the relative incidence of trauma-related ED admissions was compared with periods of patient exposure and nonexposure to MPH.
RESULTS:Among 17 381 patients prescribed MPH, 4934 had at least 1 trauma-related ED admission. The rate of trauma-related ED admission was lower during exposed periods compared with nonexposed periods (incidence rate ratio [IRR]: 0.91 [95% confidence interval (CI): 0.86-0.97]). The findings were similar only when the incident trauma episode was assessed (IRR: 0.89 [95% CI: 0.82-0.96]). A similar protective association was found in both genders. In validation analysis using nontrauma-related ED admissions as a negative control outcome, no statistically significant association was found (IRR: 0.99 [95% CI: 0.95-1.02]). All sensitivity analyses demonstrated consistent results.CONCLUSIONS: This study supports the hypothesis that MPH is associated with a reduced risk of traumarelated ED admission in children and adolescents. A similar protective association was found in both male and female patients. This protective association should be considered in clinical practice.WHAT'S KNOWN ON THIS SUBJECT: Children and adolescents with attention-deficit/hyperactivity disorder are prone to sustaining trauma that requires emergency department (ED) admission. Methylphenidate can reduce attention-deficit/ hyperactivity disorder symptoms and thus theoretically may reduce the risk of traumarelated ED admission, but previous studies did not provide a clear association.
WHAT THIS STUDY ADDS:For patients treated with methylphenidate, on-medication periods were associated with lower rates of traumarelated ED admission compared with offmedication periods. A similar protective association was found in both genders. Potential treatment benefit was greater for age $16 years. Mr Man had the original idea for the study, contributed to the development of the study, extracted data from the source database, constructed the study design and the statistical model, reviewed the literature, undertook the primary analysis, contributed to the interpretation of the analysis, and wrote the first draft of the manuscript; Dr Chan had the original idea for the study, contributed to the development of the study and the interpretation of the analysis, wrote the first draft of the manuscript, and provided oversight for all aspects of the project; Drs Coghill, Ip, Leung, and Tsui contributed to the interpretation of the...