Boston—For adults with attention-deficit/hyperactivity disorder (ADHD), poor adherence and persistence were especially significant issues for those receiving combination therapy, a new study reports.

The article in the American Journal of Managed Care notes that while treatment adherence is essential for optimal symptom control, adult patients on long-acting (LA) medications often experience inadequate symptom control using a single medication and sometimes augment their ADHD therapy.

The problem, according to researchers from the Analysis Group in Boston, is that combination versus monotherapy presented greater risks of nonadherence and nonpersistence.

“These findings suggest an unmet need for longer-acting treatments in adult patients with ADHD, which may improve adherence and ultimately prevent the long-term societal and economic consequences of undertreated and untreated ADHD,” study authors suggest.

Their retrospective observational study was designed to evaluate treatment patterns among commercially insured adults in the United States with ADHD, comparing long-acting therapy (LA), combination therapy (CT), and monotherapy.

Included in the research were adults with at least one ADHD diagnosis and at least one LA ADHD medication, as identified from the MarketScan claims database from April 1, 2009, to March 31, 2014.

The definition of CT was having filled a different ADHD medication within 30 days of the index date, as well as the two medications overlapping by 30 days or more. Without those factors, the treatment was considered monotherapy. 

Researchers measured adherence, defined as a proportion of days covered (PDC) of 0.8 or greater during the 1-year postindex date. Persistence was defined as time to discontinuation (TTD), in effect a 30-day or greater supply gap.

Overall, 225,600 eligible patients were identified—7.3% of them, mean age 29 years, receiving LA CT and 92.7%, mean age 21 years, receiving LA monotherapy.

Results demonstrate that patients receiving LA CT had notably lower adherence rates than those receiving LA monotherapy (mean PDC, 0.33 vs. 0.41; adherence rate, 7% vs. 16%, respectively; adjusted odds ratio, 0.38; P <.001). 

Significantly lower persistence was also a greater issue for the combination-therapy patients compared to participants receiving LA monotherapy (median TTD, 59 vs. 79 days, respectively; adjusted hazard ratio, 1.32; P <.001), the study team noted.
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