National survey of adherence, efficacy, and side effects of methylphenidate in children with attention-deficit/hyperactivity disorder in Taiwan.
OBJECTIVE
To identify the determinants of adherence to immediate-release (IR) methylphenidate in children and adolescents with attention-deficit/hyperactivity disorder (ADHD); to examine the impact of adherence on ADHD-related symptoms; and to compare the efficacy, adherence, and side effects of IR methylphenidate and osmotic release oral system (OROS) methylphenidate.


METHODS
This national survey, involving 12 hospitals, consisted of 2 phases of assessment. Treatment adherence in 240 (39.5%) of the 607 children aged 5 to 16 years with a clinical diagnosis of DSM-IV ADHD enrolled in the study was poor (defined as missing >or= 1 dose of ADHD medication a day and on 2 days or more during school days). Children with poor adherence at phase 1 were able to switch to OROS methylphenidate, while adherents remained on the IR variant. We reassessed 124 poor adherents who switched to OROS methylphenidate. The global ADHD severity, parent-child interaction, classroom behavior, academic performance, and side effects of the child subjects were evaluated by investigators. Parents completed the rating scales about the ADHD-related symptoms. The study began in April 2005 and was completed in February 2006.


RESULTS
Determinants for poor adherence included older age, later onset of ADHD, family history of ADHD, higher paternal education level, and multi-dose administration. Mental retardation and treatment at medical centers were inversely related to poor adherence. Overall, poor adherence was associated with more severe ADHD-related symptoms by comparison to good adherence. Similar side effect profile, superior adherence, and improved efficacy were demonstrated in intra-individual comparison of the OROS and IR methylphenidate forms.


CONCLUSIONS
Given that poor adherence to medication may be an important reason for suboptimal outcome in ADHD treatment, physicians should ensure adherence with therapy before adjusting dosage or switching medication.


BACKGROUND
clinicaltrials.gov Identifier NCT00460720.
Gau
Susan Shur-Fen
SS
Department of Psychiatry, National Taiwan University Hospital and College of Medicine, National Taiwan University, ROC. gaushufe@ntu.edu.tw
Chen
Shin-Jaw
SJ
Chou
Wen-Jiun
WJ
Cheng
Helen
H
Tang
Ching-Shu
CS
Chang
Hsueh-Ling
HL
Tzang
Ruu-Fen
RF
Wu
Yu-Yu
YY
Huang
Ya-Fen
YF
Chou
Miao-Chun
MC
Liang
Hsin-Yi
HY
Hsu
Ya-Chen
YC
Lu
Hui-Hua
HH
Huang
Yu-Shu
YS
D000293:Adolescent; D017668:Age of Onset; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy* / Q000453:epidemiology; D002391:Catchment Area, Health; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D003710:Demography; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000627:therapeutic use*; D010349:Patient Compliance / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D013624:Taiwan / Q000453:epidemiology; D016896:Treatment Outcome
D000697:Central Nervous System Stimulants; D008774:Methylphenidate