Factors associated with changes in hospitalisation in patients prescribed clozapine

Objective: The objective of this study was to examine whether delays in clozapine treatment affect outcomes once clozapine is started and identify factors that affect these outcomes. Method: Patients starting clozapine in a four year period at South London and the Maudsley NHS Foundation Trust were included. Clinical details were gathered from clinical notes. Primary outcome was net change in inpatient admissions comparing the periods before and after clozapine was started. Results: There was no significant association between the length of clozapine delay (mean clozapine delay = 3.93 years) and number or length of inpatient admissions once clozapine had been started (mean net change in days of admission = 16.74 days), F value = 0.901, p = 0.345. Clozapine reduced the total number of bed days per year, but only if treatment was continued - stopping resulted in inpatient admissions returning to pre-clozapine levels. Younger patients had a greater reduction in bed days when taking clozapine (p = 0.027). Conclusion: Clozapine reduces the number of inpatient days, regardless of the chronicity of the illness at the time clozapine was started. Continued compliance with clozapine is necessary to maintain this benefit. Reduction in bed days is greater in younger patients, suggesting early initiation of clozapine may be beneficial.