Adherence and persistence to typical and atypical antipsychotics in the naturalistic treatment of patients with schizophrenia

Original Research

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Authors: Haya Ascher-Svanum, Baojin Zhu, Douglas E Faries, Jonathan P Lacro, Christian R Dolder, Xiaomei Peng

Published Date March 2008 Volume 2008:2 Pages 67 - 77

DOI: http://dx.doi.org/10.2147/PPA.S2940

Haya Ascher-Svanum¹, Baojin Zhu¹, Douglas E Faries¹, Jonathan P Lacro², Christian R Dolder³, Xiaomei Peng¹

¹Eli Lilly and Company, Outcomes Research, Indianapolis, IN, USA; ²VA San Diego Health Care System and Department of Psychiatry, University of California, San Diego, CA, USA; ³Wingate University School of Pharmacy, Wingate, NC, USA

Objective: To compare adherence and persistence to typical versus atypical antipsychotics and between specific atypical agents in the usual care of schizophrenia and to examine the association between adherence and persistence.

Method: Data were drawn from a 3-year prospective, nonrandomized, noninterventional study of schizophrenia conducted during 1997–2003. Initiators on haloperidol, risperidone, olanzapine, quetiapine, and clozapine with at least 1 year of follow-up were included (n = 878). Adherence (Medication Possession Ratio, MPR) and persistence (time to all-cause medication discontinuation) were assessed using medical record prescription information. Analyses employed multivariate statistics adjusted for group differences.

Results: Overall, 58% of the patients were deemed adherent (MPR >80%). Adherence rates were higher: for atypical (59.4%) than typical antipsychotics (34.5%, p < 0.001), for clozapine (77%) than each comparator excluding olanzapine (p < 0.01), and for olanzapine (64%) than risperidone (57%, p = 0.027) and quetiapine (52%, p = 0.019). Differences between risperidone and quetiapine were not statistically significant. Adherence and persistence were highly correlated (r = 0.957, p < 0.001).

Conclusion: In the usual care of schizophrenia, medication adherence and persistence appear to be highly correlated and to significantly differ between typical and atypical antipsychotics and among atypical agents. The choice of antipsychotic may play a meaningful role in patients’ adherence to and persistence with antipsychotic medications.

Keywords: adherence, persistence, schizophrenia, antipsychotics

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