Pharmacological treatment patterns among patients with attention-deficit/hyperactivity disorder: retrospective claims-based analysis of a managed care population

To develop a descriptive profile of attention-deficit/hyperactivity disorder (ADHD) pharmacological treatment patterns in terms of persistence, adherence, augmentation, switching, and dosing changes; and to assess differences in treatment patterns with regard to ADHD medication type, class, and duration of action. This retrospective claims database analysis used medical data, pharmacy data, and enrollment information to examine treatment patterns among patients with at least one claim with a diagnosis code for ADHD and a filled prescription for ADHD medication (index therapy) during the period 01 January 2004 through 30 September 2006. Treatment persistence and adherence (days supplied/days persistent) were calculated. Dose changes, medication switching, and augmentation were analyzed at three levels of comparison: class (stimulant vs nonstimulant [atomoxetine]), drug type (amphetamine vs methylphenidate), and duration of action (short, intermediate, long). Statistical comparisons were made using the chi-square test for proportions and Student's t-test or the F-test from one-way ANOVA for means. Of 60,010 patients meeting eligibility criteria, 58.4% were younger than age 18. Most (78.4%) were prescribed a stimulant as their index therapy. Persistence and adherence were greater for patients on stimulants (vs the nonstimulant), for patients on amphetamines (vs methylphenidates), and for patients on long-acting medications (vs short- and intermediate-acting medications; all p < 0.0001). Index drug dose changes were least likely among individuals taking the nonstimulant (vs stimulants), methylphenidates (vs amphetamines), or intermediate-acting drugs (vs short- and long-acting drugs; all p < 0.0001), and medication switches were more frequent among those on nonstimulants, methylphenidates, or short-acting drugs (all p < 0.0001). Subjects taking long-acting medication were less likely to augment with a drug with a different duration of action than those taking intermediate- or short-acting medication (p < 0.0001). This claims-based study is limited by possible discrepancies between claims and patient behaviors (i.e., a claim for a prescription does not necessarily indicate that the medication was taken as prescribed). Patients were more stable on treatment compared with their respective comparator groups if their index therapy was a stimulant, long-acting drug, or amphetamine.