Estimated economic benefits from low-frequency administration of atypical antipsychotics in treatment of schizophrenia: a decision model

Abstract

The objective of this study was to quantify the direct medical resources used and the corresponding burden of disease in the treatment of patients with schizophrenia. Because low-frequency administration (LFA) of risperidone guarantees adherence during treatment intervals and offers fewer opportunities to discontinue, adherence and persistence were assumed to improve, thereby reducing relapses of major symptoms.A decision tree model including Markov processes with monthly cycles and a five-year maximum timeframe was constructed. Costs were adapted from the literature and discounted at a 3% annual rate. The population is a demographically homogeneous cohort of patients with schizophrenia, differentiated by initial disease severity (mildly ill, moderately ill, and severely ill). Treatment parameters are estimated using published information for once-daily risperidone standard oral therapy (RIS-SOT) and once-monthly risperidone long-acting injection (RIS-LAI) with LFA therapy characteristics derived from observed study trends. One-year and five-year results are expressed as discounted direct medical costs and mean number of relapses per patient (inpatient, outpatient, total) and are estimated for LFA therapies given at three, six, and nine month intervals.The one-year results show that LFA therapy every 3 months (LFA-3) ($6,088) is less costly than either RIS-SOT ($10,721) or RIS-LAI ($9,450) with similar trends in the 5-year results. Moreover, the model predicts that LFA-3 vs. RIS-SOT vs. RIS LAI therapy will reduce costly inpatient relapses (0.16 vs. 0.51 vs. 0.41). Extending the interval to six (LFA-6) and nine (LFA-9) months resulted in further reductions in relapse and costs.Limitations include the fact that LFA therapeutic options are hypothetical and do not yet exist and limited applicability to compare one antipsychotic agent versus another as only risperidone therapy is evaluated. However, study results have quantified the potential health state improvements and potential direct medical cost savings achievable with the development and use of LFA medication delivery technologies.

Impact of long-acting injectable antipsychotics on medication adherence and clinical, functional, and economic outcomes of schizophrenia

“…The benefit of administering LAIs was determined in patients with schizophrenia using a model created to estimate the benefits of longer intervals between injections. 49 Results of the model showed that administration every 3 months was less costly than monthly LAI and daily oral therapy. Extending the interval to 6 and 9 months further decreased the costs of therapy.…”

Quality of life of schizophrenic patients with or without depot neuroleptics

“…[46][47][48][49] Fluphenazine decanoate does not reduce relapse more than orally administered neuroleptics or other depot antipsychotics. [50][51][52][53][54] The research showed that there was small advantage of depot-forms compared to the same medicine taken orally, in terms of compatibility. However, this is not broadly applicable in everyday clinical practice.…”

Determining Clinical Follow-Up in the Context of Widening LAI Intervals

“…While very few studies have directly investigated this topic in any medical field, the few studies that have been conducted show significant unexplained practice variation. [9][10][11] Data from the Veterans Administration (VA) 12 have demonstrated that the scheduling interval has a limited impact on missed appointments, but a robust and linear effect on cancelation rates, which rise from ~ 20% at 1 month to ~ 30% by 3 months and ~ 40% by 6 months. Notably, this effect was most robust for mental health visits, for which the risk of canceling rose to nearly 70% for yearly follow-up appointments.…”