Risk of readmission in patients with schizophrenia and schizoaffective disorder newly prescribed clozapine

Abstract

Background:Insight into the effect of clozapine is limited by a lack of controlling for confounding variables in current research. Our objective was to investigate the association between clozapine prescribed at discharge, following an inpatient episode, and risk of readmission into secondary mental health services in patients with schizophrenia and schizoaffective disorder, controlling extensively for confounding variables.Methods:Clinical records from 3651 patients were analysed in a retrospective observational cohort study. Cox proportional-hazards regression models were used to assess the risk of hospital readmission. A series of sensitivity analyses were also conducted. Propensity score methods were used to address confounding-by-indication.Results:Patients on clozapine (n=202) had a reduced risk of readmission compared with patients on other antipsychotics (adjusted hazard ratio=0.79; 95% confidence interval: 0.64–0.99; p=0.043). Clozapine also had a protective effect on risk of readmission when compared with olanzapine (adjusted hazard ratio 0.76; 95% confidence interval: 0.60–0.96; p=0.021). The effect size remained consistent after adjusting for an array of possible confounders, as well as using propensity scores to address confounding-by-indication. A statistically significant result was also noted in all but two sensitivity analyses.Conclusion:Our findings suggest that clozapine is associated with a reduced risk of readmission into secondary mental health services.

Evidence-based guidelines for the pharmacological treatment of schizophrenia: Updated recommendations from the British Association for Psychopharmacology

“…Pharmaco-epidemiological studies have consistently shown that clozapine treatment is associated with a reduction in all-cause mortality (Cho et al, 2019a; Wimberley et al, 2017), and this seems to be driven by a reduction in suicidality (Meltzer and Okayli, 1995; Meltzer et al, 2003; Wimberley et al, 2017). Clozapine has been shown to reduce admission rates compared with other antipsychotics (Kesserwani et al, 2019) and in within-patient mirror-image studies (Siskind et al, 2019), and a recent meta-analysis showed lower admission rates under clozapine than any other drug, including LAIs (Land et al, 2017). Clozapine treatment is also associated with lower rates of treatment failure than any other oral antipsychotics (Tiihonen et al, 2017).…”

Clinical risk model to predict 28-day unplanned readmission via the accident and emergency department after discharge from acute psychiatric units for patients with psychotic spectrum disorders

“…35 Other research conducted in the UK found that patients with schizophrenia or schizoaffective disorder who have been newly prescribed with clozapine have a decreased risk of readmission, even if these patients had more severe psychopathology and poorer functional status. 36 A systematic review on the impact of clozapine on hospital use also found that clozapine reduced the proportion of people admitted to hospital compared with controls. 37 The authors hypothesised that the reason for this protective effect may be because of the need for ongoing regular haematological monitoring, where deteriorations in mental state may be detected earlier.…”

Clozapine prescribing: comparison of clozapine dosage and plasma levels between White British and Bangladeshi patients

“…2 Clozapine has been shown in several pharmacoepidemiological studies to show superior long-term efficacy in terms of reducing hospital admissions. 3 It also surpasses other antipsychotics in reducing self-harm 4 and overall mortality. 5 The pharmacological basis for the unique efficacy of clozapine in treatment-resistant schizophrenia is not clearly understood.…”