Meta-analysis comparing newer antipsychotic drugs for the treatment of schizophrenia: evaluating the indirect approach.

BACKGROUND: Meta-analysis is a useful method to assess the efficacy of newer antipsychotic drugs compared with older drugs or placebo. However, few trials directly compare novel drugs to each other. OBJECTIVE: The purpose of this study was to evaluate the method of indirect meta-analysis by applying it to data on olanzapine versus haloperidol and risperidone versus haloperidol to enable a comparison between olanzapine and risperidone. METHODS: Published randomized controlled trials (RCTs) of risperidone, olanzapine, and/or haloperidol were identified through literature searches (1983 to 1999) of the MEDLINE, Current Contents, and HealthSTAR databases and reviewed. Data for the Brief Psychiatric Rating Scale (BPRS) total score, the Positive and Negative Syndrome Scale (PANSS) negative subscale, the percentage of patients using anticholinergic drugs, and the percentage of patients dropping out due to lack of efficacy, side effects, or any cause were extracted and combined using the indirect method. These findings were compared with those from a direct comparative study of olanzapine and risperidone. RESULTS: The literature search yielded 8 RCTs comparing risperidone to haloperidol and 3 comparing olanzapine to haloperidol. Only 1 trial directly comparing olanzapine and risperidone was found. In this trial, the change in BPRS total and PANSS negative subscale scores tended to be higher with olanzapine by 1.80 and 1.10, respectively, but these differences were not statistically significant. Indirect meta-analysis yielded similar results. Changes in both BPRS total scores and PANSS negative subscale scores tended to be higher with olanzapine by 0.37 and 0.54, respectively, and again, the differences were not statistically significant. In the indirect meta-analysis, the rate of anticholinergic drug use was 19.5% greater among patients treated with risperidone than among patients treated with olanzapine (P < 0.05). In the direct comparative RCT, the rate was 13.1% higher among patients treated with risperidone (P < 0.05). The dropout rates were similar for patients treated with risperidone and those treated with olanzapine in both analyses. CONCLUSION: An indirect meta-analysis of studies comparing olanzapine with haloperidol and risperidone with haloperidol yielded conclusions similar to those found in a direct comparative RCT of olanzapine and risperidone.

Alzheimer's disease: a review of the disease, its epidemiology and economic impact.

This article consists of a critical review of Canadian, American and European studies published between 1976 and 1997 on the subject of Alzheimer's disease (AD), and its epidemiology, patterns of care, prognostic factors, and economic impact. As the population ages in North America and Europe, significant increases in the prevalence of AD over the next decades have been projected. The elderly population represents the largest consumer group of health care resources and the management of common diseases occurring in this population will have major medical, social, and economic implications. As a result, researchers will need to integrate the ever-increasing knowledge on AD when addressing governmental and societal concerns regarding its impact. Described herein is the study findings, limitations, and differences observed following the review of the diagnostic criteria, prevalence rates, incidence rates and risk factors. Highlighted are the areas where data is lacking. To refine current models of disease progression, and better address where health care resources and new therapies would be most beneficial, the review of predictors of institutionalization and predictive models of disease progression and survival, was performed. New research questions are indicated.