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Search Results: 1 - 10 of 462953 matches for " Ilya A Lipkovich "
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Identifying patterns in treatment response profiles in acute bipolar mania: a cluster analysis approach
Ilya A Lipkovich, John P Houston, Jonna Ahl
BMC Psychiatry , 2008, DOI: 10.1186/1471-244x-8-65
Abstract: Patients (n = 222) were selected from a randomized, double-blind study of treatment with olanzapine or divalproex in bipolar I disorder, manic or mixed episode, with or without psychotic features. Hierarchical clustering based on Ward's distance was used to identify groups of patients based on Young-Mania Rating Scale (YMRS) total scores at each of 5 assessments over 7 weeks. Logistic regression was used to identify baseline predictors for clusters of interest.Four distinct clusters of patients were identified: Cluster 1 (n = 64): patients did not maintain a response (YMRS total scores ≤ 12); Cluster 2 (n = 92): patients responded rapidly (within less than a week) and response was maintained; Cluster 3 (n = 36): patients responded rapidly but relapsed soon afterwards (YMRS ≥ 15); Cluster 4 (n = 30): patients responded slowly (≥ 2 weeks) and response was maintained. Predictive models using baseline variables found YMRS Item 10 (Appearance), and psychosis to be significant predictors for Clusters 1 and 4 vs. Clusters 2 and 3, but none of the baseline characteristics allowed discriminating between Clusters 1 vs. 4. Experiencing a mixed episode at baseline predicted membership in Clusters 2 and 3 vs. Clusters 1 and 4. Treatment with divalproex, larger number of previous manic episodes, lack of disruptive-aggressive behavior, and more prominent depressive symptoms at baseline were predictors for Cluster 3 vs. 2.Distinct treatment response profiles can be predicted by clinical features at baseline. The presence of these features as potential risk factors for relapse in patients who have responded to treatment should be considered prior to discharge.The clinical trial cited in this report has not been registered because it was conducted and completed prior to the inception of clinical trial registries.Manic episodes in bipolar disorder requiring hospitalization contribute to substantial personal and economic burden on patients, their families and society [1], which could b
Early evaluation of patient risk for substantial weight gain during olanzapine treatment for schizophrenia, schizophreniform, or schizoaffective disorder
Ilya Lipkovich, Jennie G Jacobson, Thomas A Hardy, Vicki Hoffmann
BMC Psychiatry , 2008, DOI: 10.1186/1471-244x-8-78
Abstract: Data from 669 (Study 1) and 102 (Study 2) olanzapine-treated patients diagnosed with schizophrenia, schizophreniform, or schizoaffective disorder were analyzed to identify and validate weight gain cut-offs at Weeks 1–4 that were predictive of substantial weight gain (defined as an increase of ≥ 5, 7, 10 kg or 7% of baseline weight) after approximately 30 weeks of treatment. Baseline characteristics alone, baseline characteristics plus weight change from baseline to Weeks 1, 2, 3 or 4, and weight change from baseline to Weeks 1, 2, 3, or 4 alone were evaluated as predictors of substantial weight gain. Similar analyses were performed to determine BMI increase cut-offs at Weeks 1–4 of treatment that were predictive of substantial increase in BMI (1, 2 or 3 kg/m2 increase from baseline).At Weeks 1 and 2, predictions based on early weight gain plus baseline characteristics were more robust than those based on early weight gain alone. However, by Weeks 3 and 4, there was little difference between the operating characteristics associated with these two sets of predictors. The positive predictive values ranged from 30.1% to 73.5%, while the negative predictive values ranged from 58.1% to 89.0%. Predictions based on early BMI increase plus baseline characteristics were not uniformly more robust at any time compared to those based on early BMI increase alone. The positive predictive values ranged from 38.3% to 83.5%, while negative predictive values ranged from 42.1% to 84.7%. For analyses of both early weight gain and early BMI increase, results for the validation dataset were similar to those observed in the primary dataset.Results from these analyses can be used by clinicians to evaluate risk of substantial weight gain or BMI increase for individual patients. For instance, negative predictive values based on data from these studies suggest approximately 88% of patients who gain less than 2 kg by Week 3 will gain less than 10 kg after 26–34 weeks of olanzapine treatment. An
Relationships among neurocognition, symptoms and functioning in patients with schizophrenia: a path-analytic approach for associations at baseline and following 24 weeks of antipsychotic drug therapy
Ilya A Lipkovich, Walter Deberdt, John G Csernansky, Bernard Sabbe, Richard SE Keefe, Sara Kollack-Walker
BMC Psychiatry , 2009, DOI: 10.1186/1471-244x-9-44
Abstract: Data were obtained from a clinical trial assessing the cognitive effects of selected antipsychotic drugs in patients with schizophrenia. Patients were randomly assigned to 24 weeks of treatment with olanzapine (n = 159), risperidone (n = 158), or haloperidol (n = 97). Psychosocial functioning was assessed with the Heinrichs-Carpenter Quality of Life Scale [QLS], cognition with a standard battery of neurocognitive tests; and psychiatric symptoms with the Positive and Negative Syndrome Scale [PANSS]. A path-analytic approach was used to evaluate the effects of changes in cognitive functioning on subdomains of quality of life, and to determine whether such effects were direct or mediated via changes in psychiatric symptoms.At baseline, processing speed affected functioning mainly indirectly via negative symptoms. Positive symptoms also affected functioning at baseline although independent of cognition. At 24 weeks, changes in processing speed affected changes in functioning both directly and indirectly via PANSS negative subscale scores. Positive symptoms no longer contributed to the path-analytic models. Although a consistent relationship was observed between processing speed and the 3 functional domains, variation existed as to whether the paths were direct and/or indirect. Working memory and verbal memory did not significantly contribute to any of the path-analytic models studied.Processing speed demonstrated direct and indirect effects via negative symptoms on three domains of functioning as measured by the QLS at baseline and following 24 weeks of antipsychotic treatment.Neurocognitive impairment has been found to be strongly correlated with deficits in psychosocial and occupational functioning in patients with schizophrenia [1,2]. These earlier reviews of the literature (including a meta-analysis) were focused on identifying specific neurocognitive deficits that restrict the functioning of schizophrenia patients, as opposed to the use of more global measures of n
Biplot and Singular Value Decomposition Macros for Excel
Ilya Lipkovich,Eric P. Smith
Journal of Statistical Software , 2002,
Abstract:
Double-blind, randomized trial comparing efficacy and safety of continuing olanzapine versus switching to quetiapine in overweight or obese patients with schizophrenia or schizoaffective disorder
Walter Deberdt,Ilya Lipkovich,Alexandra N Heinloth,Lin Liu
Therapeutics and Clinical Risk Management , 2008,
Abstract: Walter Deberdt1, Ilya Lipkovich2, Alexandra N Heinloth3, Lin Liu2, Sara Kollack-Walker2, Sara E Edwards2, Vicki Poole Hoffmann2, Thomas A Hardy21Eli Lilly Benelux, Eli Lilly and Company, Brussels, Belgium; 2Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA; 3i3Statprobe, Ingenix, Cary, NC, USAAbstract: We examined the potential risks and benefits of switching from olanzapine to quetiapine in mentally stable, obese, or overweight patients with schizophrenia or schizoaffective disorder. Patients receiving olanzapine were randomized to continuing olanzapine treatment (N = 68; 7.5–20 mg/day) or switching to quetiapine (N = 65; 300–800 mg/day). Time to relapse was the primary study objective; secondary objectives included changes in weight, metabolic parameters, and psychiatric symptoms, and discontinuation rates. No significant difference in time to relapse was observed (p = 0.293), but significantly more patients remained on treatment in the olanzapine group compared with the quetiapine group (70.6% vs 43.1%; p = 0.002). Olanzapine-treated patients had significantly lower rates of study discontinuation for lack of efficacy and psychiatric adverse events (AEs) compared to quetiapine (2.94% vs 15.38%, p = 0.015). Significantly more patients in the olanzapine group experienced an increase in BMI ≥1 kg/m2. Olanzapine-treated patients experienced significantly greater increases in weight from Weeks 2 through 13. Switching patients with stable disease from olanzapine to quetiapine did not significantly shorten time to relapse, but produced more frequent study discontinuations due to lack of efficacy or psychiatric AEs with moderate but variable improvement in weight and no significant between-group differences in mean changes in metabolic laboratory parameters.Keywords: antipsychotic switching, discontinuation, relapse, BMI, weight
Predictors and correlates for weight changes in patients co-treated with olanzapine and weight mitigating agents; a post-hoc analysis
Virginia L Stauffer, Ilya Lipkovich, Vicki Hoffmann, Alexandra N Heinloth, H Scott McGregor, Bruce J Kinon
BMC Psychiatry , 2009, DOI: 10.1186/1471-244x-9-12
Abstract: Data were obtained from 3 randomized, double-blind, placebo-controlled, 16-week clinical trials. Included were 158 patients with schizophrenia or bipolar disorder and a body mass index (BMI) ≥ 25 kg/m2 who had received olanzapine treatment in combination with nizatidine (n = 68), sibutramine (n = 42), or amantadine (n = 48). Individual patients were analyzed for categorical weight loss ≥ 2 kg and weight gain ≥ 1 kg. Variables that were evaluated as potential predictors of weight outcomes included baseline patient characteristics, factors of the Eating Inventory, individual items of the Eating Behavior Assessment, and the Visual Analog Scale.Predictors/correlates of weight loss ≥ 2 kg included: high baseline BMI, low baseline interest in food, and a decrease from baseline to endpoint in appetite, hunger, or cravings for carbohydrates. Reduced cognitive restraint, increase in hunger, and increased overeating were associated with a higher probability of weight gain ≥ 1 kg.The association between weight gain and lack of cognitive restraint in the presence of increased appetite suggests potential benefit of psychoeducational counseling in conjunction with adjunctive pharmacotherapeutic agents in limiting weight gain during antipsychotic drug therapy.This analysis was not a clinical trial and did not involve any medical intervention.In adult patients with serious and persistent mental illnesses such as bipolar disorder or schizophrenia, obesity is a common comorbidity. [1] Many antipsychotic medications used to treat these diseases are associated with an increased risk of weight gain. A meta-analysis by Allison and colleagues showed a significantly greater incidence of weight gain in patients treated with clozapine or olanzapine compared with patients treated with other atypical antipsychotics. [2] Since 1996, the United States (US) prescribing information for olanzapine has advised clinicians of the potential for significant weight gain in more than 1/4 of patients durin
Evaluating dose response from flexible dose clinical trials
Ilya Lipkovich, David H Adams, Craig Mallinckrodt, Doug Faries, David Baron, John P Houston
BMC Psychiatry , 2008, DOI: 10.1186/1471-244x-8-3
Abstract: To evaluate dose effect in response on primary efficacy scales from 2 randomized, double-blind, flexible-dose trials of patients with bipolar mania who received olanzapine (N = 234, 5–20 mg/day), or patients with schizophrenia who received olanzapine (N = 172, 10–20 mg/day), we used marginal structural models, inverse probability of treatment weighting (MSM, IPTW) methodology. Dose profiles for mean changes from baseline were evaluated using weighted MSM with a repeated measures model. To adjust for selection bias due to non-random dose assignment and dropouts, patient-specific time-dependent weights were determined as products of (i) stable weights based on inverse probability of receiving the sequence of dose assignments that was actually received by a patient up to given time multiplied by (ii) stable weights based on inverse probability of patient remaining on treatment by that time. Results were compared with those by unweighted analyses.While the observed difference in efficacy scores for dose groups for the unweighted analysis strongly favored lower doses, the weighted analyses showed no strong dose effects and, in some cases, reversed the apparent "negative dose effect."While na?ve comparison of groups by last or modal dose in a flexible-dose trial may result in severely biased efficacy analyses, the MSM with IPTW estimators approach may be a valuable method of removing these biases and evaluating potential dose effect, which may prove useful for planning confirmatory trials.Knowledge of the relationship between drug dose and clinical response contributes to the safe and effective use of medications. Clinical drug trials using double-blind, parallel, randomized assignment to fixed-dose groups are considered the gold standard for evaluating dose response for clinical outcomes both in exploratory and confirmatory phases of drug development. In fixed dose trials, interpretation of statistical inference can be done in terms of causal relationship between treatme
Cosmological Constant and Energy Density of Random Electromagnetic Field  [PDF]
Ilya A. Obukhov
Journal of High Energy Physics, Gravitation and Cosmology (JHEPGC) , 2016, DOI: 10.4236/jhepgc.2016.23028
Abstract: It is shown that the non-equilibrium electrically neutral and relativistically invariant vacuum-like state with the negative energy density and positive pressure may exist at the non-zero temperature in the system of spinor particles, antiparticles, and random electromagnetic field generated by particle-particle, particle-antiparticle, and antiparticle-antiparticle transitions. At the temperature of the order of 10 -5 K, the energy density of its state corresponds to the dark energy density in absolute magnitude. The cosmological constant for such material medium turns out to be negative.
Density of Vacuum-Like Plasma and Hubble Constant  [PDF]
Ilya A. Obukhov
Journal of High Energy Physics, Gravitation and Cosmology (JHEPGC) , 2017, DOI: 10.4236/jhepgc.2017.34044
Abstract: The model in which expansion of the Universe leads to a generation of non-equilibrium vacuum-like electron-positron plasma is proposed and researched. The formulas that relate the Hubble’s constant with the concentration of plasma particles and the cosmological constant are obtained. The collective properties of vacuum-like plasma are investigated. It is shown, that the coefficient of a two-photon annihilation in such plasma is nine times less than for the free particles. A simple formula for dark energy density as a function of electron mass and charge is obtained. It was demonstrated that acceleration of plasma’s chemical potential fluctuations flow proportional of dark energy density.
Transaction Costs For Innovations Diffusion
Ilya A. Romanov
European Researcher , 2012,
Abstract: The article deals with the analysis of transaction costs of the innovations distribution. The factors, affecting the innovations diffusion in accordance with the clusters, relations, dynamics of the distribution are disclosed. Transaction costs as a result of bounded rationality of economic entities are detected. The inevitability of transaction costs as an objective phenomenon is shown. Their dependence on the quality of economic information and information uncertainty is indicated. Correlative approach for the analysis of these costs is applied. The article justifies that the reduction of transaction costs increases the efficiency of innovations.
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