Pharmacoeconomics of depot antipsychotics for treating chronic schizophrenia in Sweden.

AIMS: To determine the cost-effectiveness of long-acting injectable (LAI) antipsychotics for chronic schizophrenia in Sweden. METHODS: A 1-year decision tree was developed for Sweden using published data and expert opinion. Five treatment strategies lasting 1 year were compared: paliperidone palmitate (PP-LAI), olanzapine pamoate (OLZ-LAI), risperidone (RIS-LAI), haloperidol decanoate (HAL-LAI) and olanzapine tablets (oral-OLZ). Patients intolerant/failing drugs switched to another depot; subsequent failures received clozapine. Resources and employment time lost (indirect costs) were costed in 2011 Swedish kroner (SEK), from standard government lists. The model calculated the average cost/patient and quality-adjusted life-years (QALYs), which were combined into incremental cost-effectiveness ratios. Multivariate and 1-way sensitivity analyses tested model stability. RESULTS: PP-LAI followed by OLZ-LAI had the lowest cost/patient (189,696 SEK) and highest QALYs (0.817), dominating in the base case. OLZ-LAI followed by PP-LAI cost 229,775 SEK (0.812 QALY), RIS-LAI followed by HAL-LAI cost 221,062 SEK (0.804 QALY), HAL-LAI followed by oral-OLZ cost 243,411 SEK (0.776 QALY), and oral-OLZ followed by HAL-LAI cost 249,422 SEK (0.773 QALY). The greatest proportions of costs (52.5-83.8%) were for institutional care; indirect costs were minor (2.4-3.8%). RESULTS were sensitive to adherence and hospitalization rates, but not drug cost. PP-LAI followed by OLZ-LAI dominated OLZ-LAI followed by PP-LAI in 59.4% of simulations, RIS-LAI followed by HAL-LAI in 65.8%, HAL-LAI followed by oral-OLZ in 94.0% and oral-OLZ followed by HAL-LAI in 95.9%; PP-LAI followed by OLZ-LAI was dominated in 1.1% of the 40,000 iterations. CONCLUSION: PP-LAI followed by OLZ-LAI was cost-effective in Sweden for chronic schizophrenia and cost-saving overall to the healthcare system.

Pharmacoeconomic analysis of paliperidone palmitate versus olanzapine pamoate for chronic schizophrenia in Norway.

OBJECTIVE: Paliperidone palmitate long-acting injection (PP-LAI) has recently been approved for treatment of chronic schizophrenia. Its cost-effectiveness has not been established. The objective was to compare direct costs and outcomes between PP-LAI and olanzapine pamoate (OLZ-LAI) in treating chronic schizophrenia in Norway from the perspective of the government payer. METHODS: We used a decision analytic model over a 1-year time horizon. Clinical inputs were derived from the literature and an expert panel; costs were taken from standard lists, adjusted to 2010 Norwegian kroner (NOK). Discounting was not done. Main outcomes included average cost per patient treated, hospitalisations, emergency room (ER) visits and quality-adjusted life years (QALYs). The pharmacoeconomic outcome was the incremental cost per QALY. Robustness was examined using one-way sensitivity analyses on critical variables and a 5000-iteration probabilistic Monte Carlo sensitivity analysis with all variables included. RESULTS: PP-LAI generated 0.845 QALY at a cost of 151 336 NOK of which 23% was due to drugs; 25% of patients were hospitalised and another 12% required ER visits. OLZ-LAI cost 174 351 NOK (21% due to drugs); patient outcomes included 0.844 QALY, 27% hospitalisations and 14% ER visits. PP-LAI dominated OLZ-LAI in the base case. The analysis was reasonably robust against variations in drug cost but sensitive to small changes in adherence and hospitalisation rates. Overall, PP-LAI was dominant over OLZ-LAI in 54.5% of simulations. Replacing OLZ-LAI with PP-LAI would be cost saving for the Norwegian healthcare system. CONCLUSION: PP-LAI was cost-effective compared with OLZ-LAI in treating patients with chronic schizophrenia in Norway but sensitive to changes in adherence and hospitalisation rates.