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

OBJECTIVE: 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.
METHODS: 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.
RESULTS: 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).
CONCLUSIONS: Patients were more stable on treatment compared with their respective comparator groups if their index therapy was a stimulant, long-acting drug, or amphetamine.