They had to have been hospitalized for psychotic symptoms (admission and discharge dates

available) and received at least one dose of quetiapine XR or quetiapine IR at any time during hospitalization (regardless of dose). Patients who were participating in a clinical trial during the study period or who were being treated in forensic care were excluded. Study outcomes The primary outcome was to evaluate the antipsychotic use of quetiapine XR and IR in patients with schizophrenia. Patients who received a total daily dose of at Inhibitors,research,lifescience,medical least 400 mg were regarded as being treated with quetiapine mainly for antipsychotic reasons, whilst those on a total daily dose of less than 400 mg were regarded as having been treated with quetiapine as an add-on to other antipsychotics. The cutoff dose of 400 mg quetiapine was Inhibitors,research,lifescience,medical chosen as quetiapine shows sufficient D2-receptor occupancy and thus antipsychotic properties throughout the dose range of 400–800 mg/day [Kapur et al. 2000]. The following secondary outcomes were also investigated: the use of quetiapine XR/IR treatment in high doses and in lower doses as add-on therapy; simultaneous treatment with quetiapine XR/IR; concomitant medication; patient demographics and comorbidities (ICD10

diagnosis); disease severity at hospital admission and discharge by the Global Assessment of Inhibitors,research,lifescience,medical Functioning (GAF) score; information about previous and current hospitalizations; and electroconvulsive therapy (ECT). Statistical Inhibitors,research,lifescience,medical analyses All analyses were prespecified in a statistical analysis plan and performed using the SAS software, version 9.2. Means were compared by a t test, except for GAF values when an analysis of variance was used with least squared means (LSM) and baseline GAF as covariate. Proportions were compared using a χ2 test. The percentage of patients treated with concomitant drugs was calculated using a Poison regression with length of hospital

Inhibitors,research,lifescience,medical stay as offset variable. The statistical null hypothesis was that the groups had the same average value or proportion and p values for rejecting this hypothesis were calculated. A p value below 0.05 was considered as significant. Results Patient demographics A total of 178 patients were included in the study; 118 (66%) received quetiapine XR and 60 (34%) received quetiapine IR. Demographic data were equal for the two treatment groups (Table 1). Table 1. Patient demographics. Differential dosing in patients on quetiapine XR versus quetiapine IR lifescience Significantly more patients in the quetiapine XR group (64%) compared with the quetiapine Methisazone IR group (40%) were treated with quetiapine in doses of at least 400 mg/day (p = 0.002) (Table 2). Significantly more patients receiving quetiapine XR than IR were also treated with doses of at least 600 mg/day (52% versus 23%, p = 0.0003). Moreover, 27% of the patients in the IR group had a mean quetiapine dose below 200 mg/day during the inpatient stay, while the same was seen in only 13% of the patients in the XR group. Table 2.