title: Methylphenidate and the risk of trauma.
abstract: 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 (2001-2013). 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 trauma-related 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.
authors.affiliation: Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, and.
authors.forename: Kenneth K C
authors.initials: KK
authors.lastname: Man
authors.affiliation: Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, and.
authors.forename: Esther W
authors.initials: EW
authors.lastname: Chan
authors.affiliation: Division of Medical Science, School of Medicine, University of Dundee, Dundee, United Kingdom;
authors.forename: David
authors.initials: D
authors.lastname: Coghill
authors.affiliation: Department of Non-communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom; and.
authors.forename: Ian
authors.initials: I
authors.lastname: Douglas
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China;
authors.forename: Patrick
authors.initials: P
authors.lastname: Ip
authors.affiliation: Department of Accident and Emergency, Queen Mary Hospital, Hong Kong SAR, China.
authors.forename: Ling-Pong
authors.initials: LP
authors.lastname: Leung
authors.affiliation: Department of Accident and Emergency, Queen Mary Hospital, Hong Kong SAR, China.
authors.forename: Matthew S H
authors.initials: MS
authors.lastname: Tsui
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China;
authors.forename: Wilfred H S
authors.initials: WH
authors.lastname: Wong
authors.affiliation: Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, and wongick@hku.hk.
authors.forename: Ian C K
authors.initials: IC
authors.lastname: Wong
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications / Q000188:drug therapy*; D002648:Child; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000627:therapeutic use*; D010343:Patient Admission / Q000706:statistics & numerical data; D012307:Risk Factors; D014947:Wounds and Injuries / Q000209:etiology / Q000517:prevention & control*; D055815:Young Adult
chemical_list: D008774:Methylphenidate
keywords: Hong Kong; attention-deficit/hyperactivity disorder; emergency department; self-controlled case series; trauma