Clozapine levels in inpatients with schizophrenia are not a predictor of rehospitalization: a naturalistic retrospective study
摘要
Although therapeutic drug monitoring (TDM) is recommended for personalized clozapine (CLO) dose titration, there are no widely accepted international guidelines regarding routine TDM during long-term outpatient CLO treatment and many clinicians have limited access to TDM. This retrospective, naturalistic study aimed to examine whether CLO and norclozapine (NCLO) concentrations measured only at the time of inpatient care could predict the risk of psychiatric rehospitalization after discharge, irrespective of the potential influence of confounding factors on long-term outcomes.
MethodsA total of 141 blood samples from psychiatric inpatients (71 females and 70 males, aged from 18 to 74 years) were analyzed. Serum CLO and NCLO levels were determined with high-performance liquid chromatography coupled with a UV detector. We assessed the rates of rehospitalization over 360 days after discharge.
ResultsThere was no correlation between either CLO or NCLO concentrations and psychiatric rehospitalization rates at any follow-up time points (day 90, 180, or 360). However, patients receiving CLO as a single psychotropic drug had significantly fewer rehospitalizations (assessed at 180 and 360 days of follow-up, p < 0.001) occurred among patients receiving CLO as a single psychotropic drug compared to combination therapy. The risk of rehospitalization was also higher in patients with a greater number of previous hospitalizations (OR = 1.15, p = 0.002) and in those taking additional psychotropic drugs (OR = 1.51, p = 0.010).
ConclusionsOur naturalistic retrospective study (based on an in-hospital TDM database) showed no association between the baseline steady-state CLO and NCLO levels established during hospitalization and the risk of psychiatric rehospitalization. However, the use of CLO in combination with other psychotropic drugs and the number of previous hospitalizations correlated with the risk of rehospitalization.
Clinical trial numberNot applicable.