Clinical and Economic Benefits of Long-Acting Injectable Paliperidone in Schizophrenia: A UAE-Based Modeling Study

Abstract

INTRODUCTION: Poor adherence to oral antipsychotic (OAP) therapy is a major driver of relapse in patients with schizophrenia, as only 50% or fewer patients are adherent to OAP during the first year, leading to suboptimal clinical outcomes and substantial healthcare costs. Long-acting injectable (LAI) antipsychotics enhance treatment continuity and sustained drug exposure, with real-world data showing improved effectiveness as dosing intervals lengthen due to better adherence. We evaluate the clinical and economic consequences, in the United Arab Emirates (UAE) healthcare setting, of switching patients with schizophrenia from OAPs to paliperidone LAIs with different dosing intervals, including semi-annual formulations (PP6M).
METHODS: Hazard ratios (HRs) for relapse were derived from an updated systematic review and incorporated into a Bayesian hierarchical model capturing the combined effects of route of administration and dosing frequency. Model outputs were used to populate a cost-consequence model developed from the UAE healthcare third-party payer perspective. Only direct medical costs were considered with hospitalization used as a proxy for relapse. Analyses were conducted over 1- and 5-year time horizons.
RESULTS: Over the 1-year horizon, the total budget per patient decreased by approximately 8%, 26%, and 50% following switches from OAP to paliperidone palmitate 1-month, 3-month, and 6-month formulations respectively. This corresponded to an estimated saving of ~20,000 AED per patient per year with PP6M which was associated with the lowest predicted relapse rates. Although longer-acting LAIs were associated with higher pharmaceutical expenditure per injection, reductions in relapse-related hospitalizations generated budget saving that exceeded incremental drug costs. 
CONCLUSIONS: In the UAE context, transitioning patients with schizophrenia from OAPs to paliperidone LAIs, including PP6M, may improve disease control and lead to favorable economic outcomes. Improved adherence translates into clinically meaningful  reductions in relapse, with overall cost savings driven by avoided hospitalizations, supporting broader adoption of LAI strategies.