Dose-associated changes in safety and efficacy parameters observed in a 24-week maintenance trial of olanzapine long-acting injection in patients with schizophrenia

<p>Abstract</p> <p>Background</p> <p>In a recently published 24-week maintenance study of olanzapine long-acting injection (LAI) in schizophrenia (Kane et al., 2010), apparent dose-associated changes were noted in both efficacy and safety parameters. To help clinicians balance safety and efficacy when choosing a dose of olanzapine LAI, we further studied these changes.</p> <p>Methods</p> <p>Outpatients with schizophrenia who had maintained stability on open-label oral olanzapine for 4 to 8 weeks were randomly assigned to "low" (150 mg/2 weeks; N = 140), "medium" (405 mg/4 weeks; N = 318), or "high" (300 mg/2 weeks; N = 141) dosages of olanzapine LAI for 24 weeks. Potential relationships between dose and several safety or efficacy measures were examined via regression analysis, the Jonckheere-Terpstra test (continuous data), or the Cochran-Armitage test (categorical data).</p> <p>Results</p> <p>Safety parameters statistically significantly related to dose were mean weight change (low: +0.67 [SD = 4.38], medium: +0.89 [SD = 3.87], high: +1.70 [SD = 4.14] kg, p = .024; effect size [ES] = 0.264 high vs. low dose), mean change in prolactin (low: -5.61 [SD = 12.49], medium: -2.76 [SD = 19.02]), high: +3.58 [SD = 33.78] μg/L, p = .001; ES = 0.410 high vs. low dose), fasting triglycerides change from normal at baseline to high (low: 3.2%, medium: 6.0%, high: 18.9%, p = .001; NNT = 7 high vs. low dose) and fasting high-density lipoprotein cholesterol change from normal at baseline to low (low: 13.8%, medium: 19.6%, high: 30.7%, p = .019; NNT = 6 high vs. low dose). Efficacy measures significantly related to dose included Positive and Negative Syndrome Scale total score mean change (low: +2.66 [SD = 14.95], medium: -0.09 [SD = 13.47], high: -2.19 [SD = 13.11], p <.01; ES = 0.356 high vs. low dose), relapse rate (low: 16%, medium: 10%, high: 5%, p = .003; NNT = 9 high vs. low dose), all-cause discontinuation rate (low: 36%, medium: 30%, high: 24%, p = .037; NNT = 9 high vs. low dose), and rate of discontinuation due to efficacy-related reasons (low: 20%, medium: 14%, high: 6%, p <.001). Time to all-cause discontinuation (p = .035) and time to relapse (p = .005) were also significantly related to dose.</p> <p>Conclusions</p> <p>Analyses of several safety and efficacy parameters revealed significant associations with dose of olanzapine LAI, with the highest dose generally showing greater efficacy as well as greater adverse changes in metabolic safety measures. When considering olanzapine LAI, as with all antipsychotics, it is important to carefully consider the potential benefits and risks for an individual patient.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00088491">NCT00088491</a></p

Risk of treatment-emergent diabetes mellitus in patients receiving antipsychotics

BACKGROUND: Type 2 diabetes mellitus has been reported during antipsychotic treatment. OBJECTIVE: To quantify the potential risk of treatment-emergent diabetes mellitus among patients receiving antipsychotic medications. METHODS: The MEDLINE and Psychinfo databases were searched using the key words antipsychotic (including individual drug names), diabetes, risk, and incidence for all English-language articles published between 1966 and 2005. Risk calculations were performed using data obtained from pharmacoepidemiologic studies that met the following criteria: (1) cohort design, (2) determination of preexisting diabetes, (3) inclusion of antipsychotic monotherapy as an exposure variable, and (4) comparison with exposure to first-generation antipsychotics. Studies meeting these criteria were used to calculate incidence, attributable risk between agents, and number needed to harm. RESULTS: A total of 25 observational pharmacoepidemiologic studies were found comparing antipsychotics on the outcome of diabetes mellitus. Sufficient information was provided in 15 of the reports to be able to estimate attributable risk. Attributable risk for individual second-generation antipsychotics relative to first-generation antipsychotics ranged from 53 more to 46 fewer new cases of diabetes per 1000 patients. Little observable difference was noted between the individual second-generation antipsychotics versus first-generation antipsychotics on this outcome. However, few of the studies controlled for body weight, race or ethnicity, or the presence of diabetogenic medications. None adjusted for familial history of diabetes, levels of physical activity, or diet, as this information is not usually available in the databases used in pharmacoepidemiologic studies. CONCLUSIONS: Based on the published pharmacoepidemiologic reports reviewed, the avoidance of diabetes as an outcome cannot be predictably achieved with precision by choice of a second-versus a first-generation antipsychotic. Risk management for new-onset diabetes requires the assessment of established risk factors such as family history, advancing age, non-white ethnicity, diet, central obesity, and level of physical activity