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Association between antipsychotic combination therapy and treatment adherence among individuals with bipolar disorder

Frank D. Gianfrancesco, PhD

HECON Associates, Inc., Montgomery Village, MD, USA

Martha Sajatovic, MD

Case Western Reserve University, School of Medicine, Department of Psychiatry and University, Hospitals of Cleveland, Cleveland, OH, USA

Eskinder Tafesse, PhD

AstraZeneca Pharmaceuticals LP, Wilmington, DE, USA

Ruey-Hua Wang, MS

HECON Associates, Inc., Montgomery Village, MD, USA

BACKGROUND: This study investigated the effect on antipsychotic treatment adherence of combining quetiapine or risperidone with lithium, anticonvulsants, and/or antidepressants among bipolar individuals with predominantly manic/mixed or depressive symptoms.

METHODS: Treatment episodes with quetiapine or risperidone were identified from individuals with medical claims for bipolar/manic disorder. Multiple regression analysis was used to evaluate the impact of antipsychotic combinations on treatment adherence, as measured by intensity (medication possession ratio [MPR]) and treatment duration.

RESULTS: Among mixed/manic individuals, combination therapies were associated with lower antipsychotic MPRs than monotherapy (P < .05), with MPR decreasing with number of medications. Quetiapine showed a similar pattern among depressed individuals, whereas risperidone showed a weaker association. For both subgroups, antipsychotic combinations with anticonvulsants were associated with lower MPRs than combinations with lithium. For manic/mixed individuals, combining quetiapine with an anticonvulsant and lithium was associated with shorter treatment durations than quetiapine alone (P ≤ .05). For manic/mixed individuals receiving risperidone, treatment duration was not affected by type of combination therapy. Among depressed subgroups, treatment duration was unrelated to combination therapy.

CONCLUSIONS: Adherence to quetiapine and risperidone may be affected by whether they are prescribed alone or as combination therapy, the combination strategy, and the predominant symptomatology of the individual.

KEYWORDS: combination, bipolar disorder, adherence, quetiapine, risperidone

ANNALS OF CLINICAL PSYCHIATRY 2009;21(1):3–16

CORRESPONDENCE: Frank Gianfrancesco, PhD, HECON Associates, Inc., 9833 Whetstone Drive, Montgomery Village, MD 20886 USA. E-MAIL: frank_gianfrancesco@heconassoc.com, heconassoc@comcast.net
Annals of Clinical Psychiatry ©2009 American Academy of Clinical Psychiatrists

 
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