Initiation of atypical antipsychotic agents and health outcomes in patients with schizophrenia

Systematic review of long-acting injectables versus oral atypical antipsychotics on hospitalization in schizophrenia

OBJECTIVE

To assess the impact of long-acting injectables (LAIs) versus oral antipsychotics (OAs) on hospitalizations among patients with schizophrenia by conducting a systematic literature review of studies with different study designs and performing a meta-analysis.

METHODS

Using the PubMed database and major psychiatric conference proceedings, a systematic literature review for January 2000 to July 2013 was performed to identify English-language studies evaluating schizophrenia patients treated with atypical antipsychotics. Studies reporting hospitalization rates as a percentage of patients hospitalized or as the number of hospitalizations per person per year were selected. The primary meta-analysis assessed the percentage decrease in hospitalization rates before and after treatment initiation for matched time periods. The secondary meta-analysis assessed the absolute rate of hospitalization during follow-up. Pooled treatment-effect estimates were calculated using random-effects models. To account for differences in patient and study-level characteristics between studies, meta-regression analyses were used. Subset analyses further explored the heterogeneity across study designs.

RESULTS

Fifty-eight studies evaluating 25 arms (LAIs: 13 arms, 4516 patients; OAs: 12 arms, 23,516 patients) in the primary meta-analysis and 78 arms (LAIs: 12 arms, 4481 patients; OAs: 66 arms, 96,230 patients) in the secondary meta-analysis were identified. Reduction in hospitalization rates for LAIs was 20.7 percentage points higher than that of OAs (random-effects estimates: LAIs = 56.2% vs. OAs = 35.5%, P = 0.023). Controlling for patient and study characteristics, the adjusted percentage reduction in hospitalization rates for LAIs was 26.4 percentage points higher than for OAs (95% CI: 3.3-49.5, P = 0.027). As for the secondary meta-analysis, no significant difference between LAIs and OAs was observed (random-effects estimate: -8.6, 95% CI: -18.1-1.0, P = 0.077). Subset analyses across type of study yielded consistent results. Limitations of this analysis include the long observation period, which may not reflect current treatment patterns, the use of all-cause hospitalization, which may not be solely related to schizophrenia, and the fact that most studies in the LAI cohort evaluated risperidone.

CONCLUSION

The primary results of this meta-analysis, including studies with both interventional and non-interventional designs and using meta-regressions, suggest that LAIs are associated with higher reductions in hospitalization rates for schizophrenia patients compared to OAs.

An alternative approach to measuring treatment persistence with antipsychotic agents among patients with schizophrenia in the Veterans Health Administration

Prior studies have demonstrated the importance of treatment persistence with anti-psychotic agents in sustaining control of schizophrenic symptoms. However, the conventional approach in measuring treatment persistence tended to use only the first prescription episode even though some patients received multiple prescriptions (or multiple treatment episodes) of the same medication within one year following the initiation of the index drug. In this study, we used data from the Veterans Health Administration in the United States to assess the extent to which patients received multiple prescriptions. The study found that about a quarter of the patients had two or more treatment episodes and that levels of treatment persistence tended to vary across treatment episodes. Based on these results, we offered an alternative approach in which we calculated treatment persistence with typical and atypical antipsychotic agents separately for patients with one, two, or three treatment episodes. Considering that patients with different number of treatment episodes might differ in disease profiles, this treatment episode-specific approach offered a fair comparison of the levels of treatment persistence across patients with different number of treatment episodes. Future research needs to extend the analyses beyond two antipsychotic classes to individual antipsychotic agents. A more comprehensive assessment using appropriate analytic methods should help physicians make prescription choices that will ultimately improve the care of patients with schizophrenia.

Treatment persistence: a comparison among patients with schizophrenia who were initiated on atypical antipsychotic agents

BACKGROUND

Although clinical trials have demonstrated the efficacy of atypical antipsychotic agents in reducing symptoms of schizophrenia, the likelihood of sustaining control of schizophrenic symptoms may depend on treatment persistence.

OBJECTIVE

In this study, we compared treatment persistence between patients who were initiated on risperidone or olanzapine, the two most widely prescribed atypical antipsychotic agents.

METHOD

We identified patients with schizophrenia by ICD-9-CM codes (> or =1 inpatient or > or =2 outpatient ICD-9-CM codes > or =7 days apart) between 1 July 1998 and 30 June 1999. We further selected those who were prescribed the target drug during 1 April 1999 through 31 March 2000 provided that they were not on any antipsychotic agents during the prior 6 months. Using event history analysis, we compared the treatment persistence in terms of hazard ratio between olanzapine and risperidone initiators, adjusting for patient's sociodemographic and clinical characteristics.

RESULTS

Following the initiation of the target drug, more patients switched from risperidone to olanzapine than vice versa. However, among patients with schizophrenia who had comorbid diabetes, there were more patients who made a switch from olanzapine to risperidone; whereas among those who used anxiolytics, there were more patients who switched from risperidone to olanzapine. Finally, olanzapine initiators had decreased hazards of discontinuation by 14% (unadjusted; P < 0.001) and 12% (adjusted; P = 0.002), respectively, than risperidone initiators.

CONCLUSIONS

Compared with risperidone, olanzapine seems to be better tolerated by patients as indicated by better treatment persistence. As such, initiation of olanzapine may increase the likelihood of sustaining control of symptoms of schizophrenia. Future research needs to provide a more comprehensive assessment of treatment persistence by considering other antipsychotic agents in the study and developing models to assess treatment persistence and switching as two interdependent competing risks.

Patient characteristics and the likelihood of initiation on olanzapine or risperidone among patients with schizophrenia

Although pharmacologic treatments are available for patients with schizophrenia, little is known about how prescription patterns of atypical antipsychotic agents are related to patient characteristics. In this study, we examined the association between patient characteristics and the likelihood of being initiated on olanzapine or risperidone, two of the most frequently prescribed atypical agents for schizophrenia. We selected patients who were diagnosed with schizophrenia or schizoaffective disorder based on > or = 1 inpatient or > or = 2 outpatient ICD-9-CM codes (> or = 7 days apart) between 7/1/98 and 6/30/99 from the Veterans Health Administration (VA). We classified patients into one of three types of initiation: (a) not on olanzapine or risperidone, (b) not on any atypical agents, or (c) not on any antipsychotic agents for 6 months, and then subsequently being prescribed the target drugs. Using logistic regression, we examined whether the odds ratio of being initiated on olanzapine versus risperidone are related to patient sociodemographic and clinical characteristics. Compared to risperidone initiators, olanzapine initiators used more drugs for psychiatric conditions (including antiparkinsonian agents, typical antipsychotics, and mood stabilizers) than risperidone initiators. On the other hand, risperidone initiators had more medical comorbidities and more non-psychiatric hospitalizations. Olanzapine and risperidone appear to be prescribed to patients with different characteristics. Initiation of risperidone was more common among patients who presented with more medical comorbid conditions, whereas initiation of olanzapine was more common among patient who presented with more mental comorbid conditions. Future research needs to determine the reasons for those differences.