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1.
We propose statistical definitions of the individual benefit of a medical or behavioral treatment and of the severity of a chronic illness. These definitions are used to develop a graphical method that can be used by statisticians and clinicians in the data analysis of clinical trials from the perspective of personalized medicine. The method focuses on assessing and comparing individual effects of treatments rather than average effects and can be used with continuous and discrete responses, including dichotomous and count responses. The method is based on new developments in generalized linear mixed‐effects models, which are introduced in this article. To illustrate, analyses of data from the Sequenced Treatment Alternatives to Relieve Depression clinical trial of sequences of treatments for depression and data from a clinical trial of respiratory treatments are presented. The estimation of individual benefits is also explained. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

2.
Current practice for sample size computations in clinical trials is largely based on frequentist or classical methods. These methods have the drawback of requiring a point estimate of the variance of the treatment effect and are based on arbitrary settings of type I and II errors. They also do not directly address the question of achieving the best balance between the cost of the trial and the possible benefits from using the new treatment, and fail to consider the important fact that the number of users depends on the evidence for improvement compared with the current treatment. Our approach, Behavioural Bayes (or BeBay for short), assumes that the number of patients switching to the new medical treatment depends on the strength of the evidence that is provided by clinical trials, and takes a value between zero and the number of potential patients. The better a new treatment, the more the number of patients who want to switch to it and the more the benefit is obtained. We define the optimal sample size to be the sample size that maximizes the expected net benefit resulting from a clinical trial. Gittins and Pezeshk (Drug Inf. Control 2000; 34:355-363; The Statistician 2000; 49(2):177-187) used a simple form of benefit function and assumed paired comparisons between two medical treatments and that the variance of the treatment effect is known. We generalize this setting, by introducing a logistic benefit function, and by extending the more usual unpaired case, without assuming the variance to be known.  相似文献   

3.
Clinical applications of L-glutamine: past, present, and future.   总被引:7,自引:0,他引:7  
OBJECTIVE: This review will attempt to summarize recent clinical data on glutamine's use. It will present the concept of glutamine as a "drug" or "nutraceutical," given in addition to standard nutrition support. Key references will be discussed, and clinical recommendations with regard to patients who may benefit and dosing are also provided. Recent Findings: Glutamine, traditionally considered a nonessential amino acid, now is considered "conditionally essential" after critical illness, stress, and injury. States of illness or injury can lead to a significant decrease in plasma levels of glutamine, and when this decrease is severe, it has been correlated with increased mortality. Laboratory data have demonstrated numerous benefits of glutamine in experimental models of critical illness, cancer, and cardiac injury. The mechanism of these protective effects includes attenuated proinflammatory cytokine expression, improved gut barrier function, enhanced ability to mount a stress response, improved immune cell function, and decreased mortality. Over the last 10 years, clinical trials of glutamine supplementation in critical illness, surgical stress, and cancer have shown benefit with regard to mortality, length of stay, and infectious morbidity. However, data demonstrating a lack of benefit with glutamine supplementation in some patients have been presented as well. It appears that dose and route of administration clearly influence the benefit observed from glutamine administration, with high-dose parenteral glutamine demonstrating an advantage over low-dose enteral glutamine. SUMMARY: High-dose or parenteral (> 0.25 to 0.30 g/kg/day IV or >or=30 g/day enterally) glutamine appears to demonstrate the greatest potential for benefit in hospitalized patients. No evidence of harm has been observed in studies conducted to date; thus, further clinical trials using glutamine as a pharmacologic supplement to standard nutrition are warranted.  相似文献   

4.
Surrogate endpoints are very important in regulatory decision making in healthcare, in particular if they can be measured early compared to the long-term final clinical outcome and act as good predictors of clinical benefit. Bivariate meta-analysis methods can be used to evaluate surrogate endpoints and to predict the treatment effect on the final outcome from the treatment effect measured on a surrogate endpoint. However, candidate surrogate endpoints are often imperfect, and the level of association between the treatment effects on the surrogate and final outcomes may vary between treatments. This imposes a limitation on methods which do not differentiate between the treatments. We develop bivariate network meta-analysis (bvNMA) methods, which combine data on treatment effects on the surrogate and final outcomes, from trials investigating multiple treatment contrasts. The bvNMA methods estimate the effects on both outcomes for all treatment contrasts individually in a single analysis. At the same time, they allow us to model the trial-level surrogacy patterns within each treatment contrast and treatment-level surrogacy, thus enabling predictions of the treatment effect on the final outcome either for a new study in a new population or for a new treatment. Modelling assumptions about the between-studies heterogeneity and the network consistency, and their impact on predictions, are investigated using an illustrative example in advanced colorectal cancer and in a simulation study. When the strength of the surrogate relationships varies across treatment contrasts, bvNMA has the advantage of identifying treatment comparisons for which surrogacy holds, thus leading to better predictions.  相似文献   

5.
OBJECTIVE: Genetic testing for adult-onset, common diseases is becoming more commonplace in clinical medicine. We modeled the proportions of hypothetic populations that would potentially benefit or suffer harm from widespread predisposition testing. METHODS: Using the traditional two-by-two table from the discipline of epidemiology, we modeled three hypothetic populations using the example of genetic testing for hereditary colorectal cancer in three groups: the general population, a genetically increased-risk population, and a population at increased risk due to nongenetic factors. RESULTS: We demonstrate that the potential benefits are increased and risks are reduced when testing is limited to those at increased genetic risk when compared with testing in the general population. Where disease incidence is increased due to nongenetic factors, genetic testing has the potential to detract from the detection and reduction of other potentially important risk factors. CONCLUSION: While targeted testing can benefit those truly at increased risk, broadly applied genetic testing can do more harm than good.  相似文献   

6.
Results of randomized clinical trials are the preferred "evidence" for establishing the benefits and safety of medical treatments. We present evidence suggesting that the conventional approach to reporting clinical trials has fundamental flaws that can result in overlooking identifiable subgroups harmed by a treatment while underestimating benefits to others. A risk-stratified approach can dramatically reduce the chances of such errors. Since professional and economic incentives reward advocating treatments for as broad a patient population as possible, we suggest that payers and regulatory bodies might need to act to motivate prompt, routine adoption of risk-stratified assessments of medical treatments' safety and benefits.  相似文献   

7.
Motivated by a recent National Research Council study, we discuss three aspects of the analysis of clinical trials when participants prematurely discontinue treatments. First, we distinguish treatment discontinuation from missing outcome data. Data collection is often stopped after treatment discontinuation, but outcome data could be recorded on individuals after they discontinue treatment, as the National Research Council study recommends. Conversely, outcome data may be missing for individuals who do not discontinue treatment, as when there is loss to follow up or missed clinic visits. Missing outcome data is a standard missing data problem, but treatment discontinuation is better viewed as a form of noncompliance and treated using ideas from the causal literature on noncompliance. Second, the standard intention to treat estimand, the average effect of randomization to treatment, is compared with three alternative estimands for the intention to treat population: the average effect when individuals continue on the assigned treatment after discontinuation, the average effect when individuals take a control treatment after treatment discontinuation, and a summary measure of the effect of treatment prior to discontinuation. We argue that the latter choice of estimand has advantages and should receive more consideration. Third, we consider when follow‐up measures after discontinuation are needed for valid measures of treatment effects. The answer depends on the choice of primary estimand and the plausibility of assumptions needed to address the missing data. Ideas are motivated and illustrated by a reanalysis of a past study of inhaled insulin treatments for diabetes, sponsored by Eli Lilly. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

8.
《Value in health》2020,23(5):616-624
ObjectivesIn a previous project aimed at informing patient-centered care for people with multiple chronic conditions, we performed highly stratified quantitative benefit–harm assessments for 2 top priority questions. In this current work, our goal was to describe the process and approaches we developed and to qualitatively glean important elements from it that address patient-centered care.MethodsWe engaged patients, caregivers, clinicians, and guideline developers as stakeholder representatives throughout the process of the quantitative benefit–harm assessment and investigated whether the benefit–harm balance differed based on patient preferences and characteristics (stratification). We refined strategies to select the most applicable, valid, and precise evidence.ResultsTwo processes were important when assessing the balance of benefits and harms of interventions: (1) engaging stakeholders and (2) stratification by patient preferences and characteristics. Engaging patients and caregivers through focus groups, preference surveys, and as co-investigators provided value in prioritizing research questions, identifying relevant clinical outcomes, and clarifying the relative importance of these outcomes. Our strategies to select evidence for stratified benefit–harm assessments considered consistency across outcomes and subgroups. By quantitatively estimating the range in the benefit–harm balance resulting from true variation in preferences, we clarified whether the benefit–harm balance is preference sensitive.ConclusionsOur approaches for engaging patients and caregivers at all phases of the stratified quantitative benefit–harm assessments were feasible and revealed how sensitive the benefit–harm balance is to patient characteristics and individual preferences. Accordingly, this sensitivity can suggest to guideline developers when to tailor recommendations for specific patient subgroups or when to explicitly leave decision making to individual patients and their providers.  相似文献   

9.
There is accumulating evidence from clinical trials and cohort studies that highly active antiretroviral combination therapy is effective at halting immunologic and clinical progression of human immunodeficiency virus (HIV). Its impact at a population level is less well known because the regimes may be difficult to tolerate and compliance poorer. The authors make use of population data for almost all of the HIV-infected people in Scotland in 1997 who were under clinical care and monitor their response to therapy during the first year when these effective treatments became widely available. More than two thirds of the HIV-positive patients were on some form of antiretroviral therapy during the year. The authors show that all treated groups, even those who were on changing regimes, showed net improvement in immunologic status during the year. For the group of patients on triple or quadruple therapy, there was an average increase of more than 100 CD4 cells/mm(3) over the year, with other treatment groups showing more modest, but significant, increases.  相似文献   

10.
Adjuvant treatments can be added to primary curative cancer treatments to increase the probability of survival. However, these treatments have side effects. Research into what additional probability of survival cancer patients require from an adjuvant treatment before they consider it worthwhile, has been carried out in hypothetical situations. The published literature on this subject shows that the additional benefit which patients expect is small. Yet, variation in patient preferences within studies is large. Preferences regarding additional benefit are not consistently associated with patient socio-demographic or disease characteristics. It is very likely that new patients who face the choice of adjuvant treatment will greatly differ from each other in the benefit that they require from it. In order to give individualized recommendations, specialists need to ask the patient which benefits and disadvantages he or she considers to be important.  相似文献   

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