title: Impact of methylphenidate formulation on treatment patterns and hospitalizations: a retrospective analysis.
abstract: BACKGROUND
  While stimulant therapy has been shown to be effective in the treatment of attention-deficit/hyperactivity disorder (ADHD), there is less information concerning differences between alternative stimulant medications. The purpose of this study is to examine how different formulations of methylphenidate (MPH) affect treatment patterns and hospitalizations.
  
  
  METHODS
  From a large claims database we retrospectively identified individuals age 6 or older who were diagnosed with ADHD and who received either once daily, extended-release oral system methylphenidate (OROS MPH) (e.g., Concerta) or three-times daily immediate-release generic methylphenidate (TID MPH). There were 5,939 individuals included in the analysis--4,785 who initiated therapy with OROS MPH and 1,154 who initiated therapy with TID MPH. We used Analyses of Covariance (ANCOVAs) to examine differences in treatment patterns between individuals who initiated therapy on OROS MPH and those who initiated therapy on TID MPH. We used logistic and negative binomial multivariate regressions to examine the probability of being hospitalized and the hospital length of stay.
  
  
  RESULTS
  Controlling for demographic characteristics, patient general health status, and comorbid diagnoses, significantly fewer individuals who initiated therapy with OROS MPH had a 15-day gap in therapy (85% vs. 97%, p < 0.0001 or a 30-day gap in therapy (77% vs. 95%, p < 0.0001) or switched to another ADHD medication (27% vs. 68%, p < 0.0001). Individuals who initiated therapy with OROS MPH stayed on therapy significantly longer (199 vs. 108 mean days, p < 0.0001) and more individuals received medication for 90% (24% vs. 5%, p < 0.0001), 80% (29% vs. 7%, p < 0.0001), or 75% (30% vs. 7%, p < 0.0001) of the days during the first year post initiation of therapy. Individuals who initiated therapy on OROS MPH were also significantly less likely to be hospitalized (odds ratio = 0.67, p = 0.0454) and stayed, on average, 0.69 fewer days in the hospital (p = 0.0035).
  
  
  CONCLUSIONS
  Results demonstrate that among individuals diagnosed with ADHD who receive either OROS MPH or TID MPH, the use of OROS MPH is associated with fewer gaps in medication, less switches in medication, and more days on intent-to-treat therapy. In addition, use of OROS MPH compared to TID MPH was associated with improved outcomes, as measured by the reduced use of hospitalizations.
authors.affiliation: McNeil Consumer and Specialty Pharmaceuticals, Fort Washington PA 19034, USA. jkemner@ethus.jnj.com
authors.forename: Jason E
authors.initials: JE
authors.lastname: Kemner
authors.forename: Maureen J
authors.initials: MJ
authors.lastname: Lage