Objectives: Schizophrenia is a severe mental illness with heterogeneous aetiology, range of symptoms and course of illness. Cost-effectiveness analysis often applies averages from populations, which disregards patient heterogeneity even though there are a range of methods available to acknowledge patient heterogeneity. This review evaluates existing economic evaluations of interventions in schizophrenia to understand how patient heterogeneity is currently reflected in economic evaluation.
Methods: Electronic searches of the MEDLINE, Embase, and PsycINFO via Ovid, and the Health Technology Assessment database were run to identify full economic evaluations of interventions aiming to reduce the symptoms associated with schizophrenia. Two levels of screening were used, and explicit inclusion criteria were applied. Pre-specified data extraction and critical appraisal were performed.
Results: Seventy-six relevant studies were identified. Over half (41/76) of the papers acknowledged patient heterogeneity in some way through discussion or methods. There was a range of patient characteristics considered, including demographics and socioeconomic factors (e.g., age, educational level, ethnicity), clinical characteristics (e.g., symptom severity, comorbidities) and preferences (e.g., preferences related to outcomes or symptoms). Subgroup analyses were rarely reported (8/76).
Conclusions: Patient heterogeneity was frequently mentioned in studies but was rarely thoroughly investigated in the identified economic evaluations. When investigated, included patient characteristics and methods were heterogeneous. Understanding and acknowledging patient heterogeneity may alter the conclusions of cost-effectiveness evaluations, subsequently we would encourage further research in this area.