Hospitalization and cost after switching from atypical to typical antipsychotics in schizophrenia patients in Thailand

Tuanthon Boonlue,1,2 Suphat Subongkot,1,2 Piyameth Dilokthornsakul,3,4 Ronnachai Kongsakon,5 Oraluck Pattanaprateep,6 Orabhorn Suanchang,7 Nathorn Chaiyakunapruk3,8–10 1Clinical Pharmacy Division, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, Thailand; 2The College of Pharmacotherapy of Thailand, Nonthaburi, Thailand; 3Center of Pharmaceutical Outcomes Research, Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand; 4Center for Pharmaceutical Outcomes Research, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, USA; 5Department of Psychiatry, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 6Department of Health Informatics, Ramathibodi Hospital, Mahidol University, 7Department of Pharmacy, Somdet Chaopraya Institute of Psychiatry, Bangkok, Thailand; 8School of Pharmacy, Monash University Malaysia, Selangor, Malaysia; 9School of Population Health, University of Queensland, Brisbane, Australia; 10School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA Background: Several clinical practice guidelines suggest using atypical over typical antipsychotics in patients diagnosed with schizophrenia. Nevertheless, cost-containment policy urged restricting usage of atypical antipsychotics and switching from atypical to typical antipsychotics. Objective: This study aimed to evaluate clinical and economic impacts of switching from atypical to typical antipsychotics in schizophrenia patients in Thailand. Methods: From October 2010 through September 2013, a retrospective cohort study was performed utilizing electronic database of two tertiary hospitals. Schizophrenia patients aged 18 years or older and being treated with atypical antipsychotics were included. Patients were classified as atypical antipsychotic switching group if they switched to typical antipsychotics after 180 days of continual atypical antipsychotics therapy. Outcomes were schizophrenia-related hospitalization and total health care cost. Logistic and Poisson regression were used to evaluate the risk of hospitalization, and generalized linear model with gamma distribution was used to determine the health care cost. All analyses were adjusted by employing propensity score and multivariable analyses. All cost estimates were adjusted according to 2013 consumer price index and converted to US$at an exchange rate of 32.85 Thai bahts/US$. Results: A total of 2,354 patients were included. Of them, 166 (7.1%) patients switched to typical antipsychotics. The adjusted odds ratio for schizophrenia-related hospitalization in atypical antipsychotic switching group was 1.87 (95% confidence interval [CI] 1.23–2.83). The adjusted incidence rate ratio was 2.44 (95% CI 1.57–3.79) for schizophrenia-related hospitalizations. The average total health care cost was lower in patients with antipsychotic switching (–$64; 95$459 to $332). Conclusion: Switching from atypical to typical antipsychotics is associated with an increased risk of schizophrenia-related hospitalization. Nonetheless, association with average total health care cost was not observed. These findings can be of use as a part of evidence in executing prospective cost-containment policy. Keywords: antipsychotic switching, schizophrenia, hospitalization, cost, atypical antipsychotics, typical antipsychotic