Treatment persistence in attention deficit/hyperactivity disorder: a retrospective analysis of patients initiated on lisdexamfetamine vs other medications.

OBJECTIVE: To compare treatment persistence in attention-deficit/hyperactivity disorder (ADHD) of patients initiated on lisdexamfetamine (LDX) vs other ADHD medications.
METHODS: A large US administrative claims database was used to select ADHD patients who initiated an ADHD medication (index treatment) during/after 2007. Patients were classified, based on age and previous treatment status, as treatment-naïve or previously treated children and adolescents (6-17 years) and treatment-naïve or previously treated adults (18 years and older). Furthermore, patients were classified into seven mutually exclusive treatment groups, based on their index treatment: LDX, atomoxetine (ATX), osmotic-release methylphenidate hydrochloride long-acting (OROS MPH), other methylphenidate/dexmethylphenidate short-acting (MPH SA) and long-acting (MPH LA), and amphetamine/dextroamphetamine short acting (AMPH SA) and long-acting (AMPH LA). Treatment persistence, analyzed through discontinuation (interruption of the index treatment for ≥30 consecutive days), was compared between treatment groups using multivariate Cox proportional hazards. Patients were followed until first treatment discontinuation or up to 12 months after the initiation of the index treatment, whichever occurred first.
RESULTS: Among children and adolescents, LDX patients had a significantly lower discontinuation rate compared to other treatment groups (range hazard ratios [HRs]; 1.04-2.26; all p < 0.05), except when compared to treatment-naïve patients on ATX and OROS MPH, where no statistically significant differences were found and where LDX had a higher risk of discontinuation, respectively. Among adults, LDX patients had a significantly lower discontinuation rate compared to patients in other treatment groups (range HR; 1.14-1.86; all p < 0.05), except for the comparison with AMPH LA patients, where differences were not statistically significant. LIMITATIONS: This study did not control for ADHD severity.
CONCLUSION: LDX-treated patients were associated with higher persistence compared to patients initiated on other ADHD medications, except for the comparisons with OROS MPH and ATX treated patients in treatment-naïve children and adolescents and AMPH LA-treated patients in adults.