The study aimed to assess the occurrence of overlapping prescriptions for methylphenidate among children and adolescents with newly diagnosed attention-deficit hyperactivity disorder (ADHD) and to evaluate the extent to which physician-level and patient-level characteristics affected the risk of prescription overlap during a one-year treatment period.
The analytic sample comprised 3,081 incident cases of ADHD in 2002 involving children aged 17 years or younger from a retrospective cohort study in Taiwan. Medical and pharmacy claims data from 1999 to 2002 were retrieved from the National Health Insurance Program. All records of methylphenidate prescriptions within a year of treatment initiation were retrieved for each patient, and the number of overlapping days for any two successive prescriptions (new, renewal, or refill) was measured. Multilevel analyses were performed to identify predictors of methylphenidate prescription overlap.
Within a year of treatment initiation, approximately 3% to 4% individuals with a new diagnosis of ADHD had experienced methylphenidate prescription overlap. Youngsters who resided in a rural region (adjusted odds ratio [AOR]=2.68) or who had ever changed prescribing doctors (AOR=3.04) were more likely to have visits with a methylphenidate prescription overlap. Receiving methylphenidate from physicians aged 46 or older was associated with 3.6-fold increased odds of prescription overlap.
In an effort to improve the quality and safety of prescription of controlled substances in younger populations, interventions or policies should be devised to target both the service providers and the patients.