Treatment Patterns, Adherence, and Persistence in ADHD: A Canadian Perspective

Objective: To understand attention-deficit/hyperactivity disorder (ADHD) treatment patterns and estimate adherence and persistence in Quebec, Canada. Design: This cross-sectional, retrospective prescription claims analysis used a random sample of 15 838 patients with ADHD from a Quebec database (Regie de l'assurance maladie du Quebec [RAMQ]) to assess treatment patterns, adherence (1-year medication possession ratio in new users), and persistence (proportion persistent at 3, 6, and 12 months after index prescription). Results: The mean patient age was 14 years; 72.6% were male. During the 5-year study period (2004-2009), 416 646 ADHD prescriptions were filled. Short-acting (SA) medications declined from 72.8% to 26.4% of all claims, while stimulant and nonstimulant long-acting (LA) medications increased from 27.2% to 73.6%. Approximately half of the patients used both SA and LA medications (either concomitantly or subsequently), and the others used only SA (30%) or LA (19%) drugs. Among patients using both, switching from SA to LA was the most frequent (27.9%) treatment pattern. More patients on LA methylphenidates (6.4%) compared with LA amphetamines (1.9%; P < 0.01) required augmentation with an SA drug. Fewer patients on SA stimulants (39.4%) were >= 80% adherent compared with LA stimulants (63%; P < 0.001) and LA nonstimulants (60.2%; P < 0.001). More patients on LA stimulants (81.1%) were persistent at 12 months compared with LA nonstimulants (61.7%; P < 0.001) and SA stimulants (59.6%; P < 0.001). Similar trends were observed at all time points measured. Conclusions: Switching from SA to LA medications and treatment augmentation are common in ADHD management, with implications for patient care and health care resource use. This analysis found poor adherence in ADHD treatment, although adherence and persistence were improved with LA stimulant formulations.