Real-World Evidence of the Clinical and Economic Impact of Long-Acting Injectable Versus Oral Antipsychotics Among Patients with Schizophrenia in the United States: A Systematic Review and Meta-Analysis

Background Long-acting injectable (LAI) antipsychotics, compared with oral antipsychotics (OA), have been found to significantly improve patient outcomes, including reduced hospitalizations and emergency room (ER) admissions and increased medication adherence among adult patients with schizophrenia. In turn, the clinical benefits achieved may translate into lower economic burden. Real-world evidence of the comparative effectiveness of LAI is needed to understand the potential benefits of LAI outside of the context of clinical trials. This study aimed to provide a comprehensive synthesis of recent published real-world studies comparing healthcare utilization, costs, and adherence between patients with schizophrenia treated with LAI versus OA in the United States. Methods In this systematic literature review, MEDLINE® was searched for peer-reviewed, real-world studies (i.e., retrospective or pragmatic designs) published in English between January 1, 2010 and February 10, 2020. Comparative studies reporting hospitalizations, ER admissions, healthcare costs, or medication adherence (measured by proportion of days covered [PDC]) in adults with schizophrenia treated with LAI versus OA (or pre- vs post-LAI initiation) in the United States were retained. Random effects meta-analyses were conducted among eligible studies to evaluate the association of LAI versus OA use on hospitalizations, ER admissions, healthcare costs, and treatment adherence. A sensitivity analysis among the subset of studies that compared OA with paliperidone palmitate once monthly (PP1M), specifically, was conducted. Results A total of 1083 articles were identified by the electronic literature search, and two publications were manually added subsequently. Among the 57 publications meeting the inclusion criteria, 25 provided sufficient information for inclusion in the meta-analyses. Compared with patients treated with OA, patients initiated on LAI had lower odds of hospitalization (odds ratio [OR] 0.62, 95% confidence interval [CI] 0.54–0.71, n = 7), fewer hospitalizations (incidence rate ratio [IRR] [95% CI] 0.75 [0.65–0.88], n = 9), and fewer ER admissions (IRR [95% CI] 0.86 [0.77–0.97], n = 6). The initiation of LAI was associated with higher per-patient-per-year (PPPY) pharmacy costs (mean difference [MD] [95% CI] $5603 [3799–7407], n = 6), which was offset by lower PPPY medical costs (MD [95% CI] − $5404 [− 7745 to − 3064], n = 6), resulting in no significant net difference in PPPY total all-cause healthcare costs between patients treated with LAI and those treated with OA (MD [95% CI] $327 [− 1565 to 2219], n = 7). Patients initiated on LAI also had higher odds of being adherent to their medication (PDC ≥ 80%; OR [95% CI] 1.89 [1.52–2.35], n = 9). A sensitivity analysis on a subset of publications evaluating PP1M found results similar to those of the main analysis conducted at the LAI class level. Conclusions Based on multiple studies with varying sub-types of patient populations with schizophrenia in the United States published in the last decade, this meta-analysis demonstrated that LAI antipsychotics were associated with improved medication adherence and significant clinical benefit such as reduced hospitalizations and ER admissions compared with OA. The lower medical costs offset the higher pharmacy costs, resulting in a non-significant difference in total healthcare costs. Taken together, these findings provide strong evidence on the clinical and economic benefits of LAI compared with OA for the treatment of schizophrenia in the real world. Supplementary Information The online version contains supplementary material available at 10.1007/s40263-021-00815-y.