The impact on schizophrenia-related hospital utilization and costs of switching to long-acting risperidone injections in Sweden.

Aim: To estimate changes in resource usage, hospitalization rates, and costs in actual practice in Sweden for schizophrenia patients after switching to long-acting injectable risperidone (Risperdal Consta).

Methods: A retrospective chart review within-subject mirror-image study using actual practice chart review data was used to compare annual hospital bed-days and annual hospital episodes for adults with schizophrenia or schizoaffective disorder before and after switching to Risperdal Consta in the period 1 January 2003 to 30 June 2005. Secondary endpoints included mean length of hospital stay per episode, the cost of hospitalization, and the cost of antipsychotic treatment. The base case analytical approach allocated all hospital episodes overlapping the switch date entirely to pre-switch treatment. In order to investigate the impact of inpatient care ongoing at the time of the switch, the change in bed-days per year was also estimated using an alternative analytical approach inspired by economic modelling.

Results: One-hundred sixty-four patients were enrolled at nine geographically diverse sites. The switch to Risperdal Consta was associated with a significant reduction in mean annual days in hospital from 39 to 21 days per year (45%), which was linked to a significant reduction in the number of hospitalizations from 0.86 to 0.63 per year (27%). The alternative "modelling-inspired" estimate of the reduction in mean annual days in hospital was also 27%.

Conclusion: A naturalistic mirror-image study found that switching to long-acting injectable risperidone led to sizeable reductions in inpatient resource use. These results coincide with the findings of other international studies.