Long-term antipsychotic polypharmacy prescribing in secondary mental health care: detection, predictors and outcomes.

摘要

Background: Investigating long-term antipsychotic polypharmacy is key tounpacking the associations between serious mental illnesses (SMI) anddetrimental outcomes, such as premature death and frequent hospitalreadmissions, observed in this population. However, existing research issparse and hampered by methodological problems such as examining smalland homogeneous samples and residual confounding.Objectives:1) To identify cases on long-term antipsychotic polypharmacy (≥ 6 months)prescribing in South London and Maudsley electronic health records (EHR);2) To identify factors that predict long-term antipsychotic polypharmacyprescribing for SMI patients in secondary mental health care;3) To investigate whether outcomes such as hospital readmission andmortality are associated with long-term antipsychotic polypharmacyprescribing in secondary mental health care.Methods: Antipsychotic medication information was derived from the ClinicalRecord Interactive Search (CRIS), a de-identified electronic patient recordssystem, for the period between 2007 and 2014. Data on mortality wereextracted using existing linkages between CRIS and death certification (Officeof National Statistics). Information about antipsychotic co-prescribing wasextracted using a bespoke algorithm. Multivariable logistic models were builtto investigate predictors of antipsychotic polypharmacy. To investigate theimpact of antipsychotic polypharmacy on hospital readmission and all-causemortality, I constructed multivariable Cox proportion hazard models. To testthe association between long-term antipsychotic polypharmacy and cause-specific mortality I used competing risk regression.Implications: On a clinical level, this thesis provides an insight into factorsthat can predict clinical decision-making regarding antipsychoticpolypharmacy prescribing in real-life clinical settings. On a patient level, thefindings highlight patient burden associated with this antipsychotic regimen. Inthe wider treatment, service and policy context, the lack of patient benefit fromantipsychotic polypharmacy highlights the need for programmes that targetprescribers, to reduce antipsychotic polypharmacy.