Comparison of clinical outcomes in patients with schizophrenia following different long-acting injectable event-driven initiation strategies

This retrospective study evaluated the benefit of following different long-acting injectable (LAI) initiation strategies based on the timing of behavioral and clinical events among Medicaid beneficiaries with schizophrenia. Adults with schizophrenia initiating oral antipsychotics (OAPs) after 12 months without antipsychotic use or schizophrenia-related inpatient/emergency room (ER) visits (index date) were identified. Patients were categorized into four event-driven LAI initiation strategy cohorts based on observed sequences of behavioral (i.e., OAP adherence) and clinical (i.e., schizophrenia-related inpatient/ER visits) events between index and LAI initiation or censoring—strategy #1: adherent to OAPs without schizophrenia-related inpatient/ER visits; strategy #2: nonadherent to OAPs without schizophrenia-related inpatient/ER visits; strategy #3: one schizophrenia-related inpatient/ER visit; strategy #4: ≥2 schizophrenia-related inpatient/ER visits. Clinical outcomes (i.e., all-cause inpatient/ER visits) were evaluated between OAP initiation and end of follow-up. Comparisons between LAI initiation strategy cohorts were conducted using a dynamic marginal structural model adjusting for baseline characteristics and time-varying confounders. Among 13,444 eligible patients, 13.1%, 53.6%, 15.7%, and 17.6% were following strategies #1–4, respectively; of these, 21.9%, 4.3%, 9.2%, and 6.5% started an LAI (the remaining were censored). Strategy #1 was associated with a greater clinical benefit, with 43%, 69%, and 80% fewer inpatient days (all p < 0.05); and 57%, 59%, and 79% fewer ER visits (all p < 0.01) vs strategies #2–4, respectively; the clinical benefit was also observed for strategy #2 vs #3–4. Therefore, starting an LAI prior to OAP nonadherence or occurrence of a schizophrenia-related inpatient/ER visit was associated with fewer all-cause inpatient days of inpatient stay and ER visits.