A Pharmacoeconomic analysis of compliance gains on antipsychotic medications
- 63 Downloads
Compliance among patients with schizophrenia is typically poor. Consequently, treatments that are equally efficacious under trial-based conditions but face different compliance rates in clinical practice (e.g. due to adverse-effect profile, ease of use, reputation) may have differences in effectiveness not observed during trials. This study analyses the impact of differences in compliance with atypical antipsychotics using a pharmacoeconomic discrete-event simulation (DES) model, adapted to the Swedish treatment setting.
An existing 5-year DES model was adapted to reflect a Swedish setting; the analysis was conducted from a third-party payer perspective, with only direct costs included.
The two treatment arms were identical except for percentage of compliant patients. Non-compliant patients experienced shorter time between relapses and had inferior symptom control than their compliant counterparts. The difference in compliance rates was varied from 0% to 15%, and incremental costs and effects were recorded and analysed.
With a 5%, 10% and 15% difference in compliance rate, incremental effects increased to 0.021, 0.037 and 0.062, respectively, while generating cost savings of Swedish kronor (SEK)31 500, SEK62 000 and SEK104 500, respectively (SEK9.25 = €1, year 2007 values). Hence, each percentage point of compliance gain is predicted to roughly result in a cost saving of SEK6000 and a QALY gain of 0.004. On average, the model predicts that, with a 15% increase in compliance, 0.5 relapses are prevented, the average Positive And Negative Syndrome Scale (PANSS) score decreases by 3.3 points and patients spend 22 fewer days in hospital over 5 years.
The DES model predicts that increases in compliance may lead to considerable cost savings and health improvements. Therefore, when determining the cost effectiveness of a new antipsychotic, efficacy rates from clinical trials should not be taken at face value, but should be interpreted in tandem with expectations concerning compliance, in light of product characteristics such as adverse effects. These results further suggest that efforts to improve compliance among patients with schizophrenia are expected to prove cost effective if compliance gains and the resulting health improvements and cost savings are in balance with the additional costs.
KeywordsSchizophrenia Atypical Antipsychotic Compliance Rate Medication Possession Ratio Compliant Patient
Joep Damen and Bart Heeg worked as consultants for Janssen-Cilag for the purpose of this study. Mickael Lothgren is an employee of Janssen-Cilag. Funding for this study was provided by Janssen-Cilag.
- 11.Marder SR. Overview of partial compliance. J Clin Psychiatry 2003; 64 Suppl. 16: 3–9Google Scholar
- 14.Heeg BMS, Buskens E, Knapp M, et al. Modelling the treated course of schizophrenia: development of a discrete event simulation model. Pharmacoeconomics 2005; 23 Suppl. 1: 17–33Google Scholar
- 18.Travis MJ, Peters E, Kerwin R. Managing relapse in schizophrenia. Institute of psychiatry. London: Science Press, 2001Google Scholar
- 20.Heeg B, Buskens E, Botteman M, et al. The cost-effectiveness of atypicals in the UK. Value Health. Epub 2008 May 15Google Scholar
- 27.Health Care Insurance Board. Pharmacopoeia the Netherlands. Amstelveen: Health Care Insurance Board, 2002Google Scholar
- 33.Regionsjukvårdsnämnden. Prices and reimbursement of healthcare in the South East region 2007. Regional Board of Healthcare [in Swedish online]. Available from URL: http://www.lio.se [Accessed 2009 Mar 24]
- 34.Socialstyrelsen och Statistiska centralbyrån. Comparative number for the social service year 2005. National Board of Health 2006 [in Swedish online]. Available from URL: http://www.socialstyrelsen.se/NR/rdonlyres/B5262E3E-F63C-46C6-95C3-CF83A37668CC/6199/20061258_rev.pdf [Accessed 2009 Mar 24]Google Scholar
- 35.Statistics Sweden. CPI: indices for main groups, annual averages. March 2008 [online]. Available from URL: http://www.scb.se/Pages/TableAndChart_33908.aspx [Accessed 2009 Mar 24]
- 36.Pharmaceutical Benefits Board Sweden. General guidelines for economic evaluations from the Pharmaceutical Benefits Board (LFNAR 2003: 2) [online]. Available from URL: http://www.tlv.se/Upload/English/ENG-lfnar-2003-2.pdf [Accessed 2009 Mar 24]
- 37.FXCM Active Trader [online]. Available from URL: http://www.x-rates.com [Accessed 2007 Aug 2]