Response-adaptive trial designs with accelerated Thompson sampling

In a clinical trial, sometimes it is desirable to allocate as many patients as possible to the best treatment, in particular, when a trial for a rare disease may contain a considerable portion of the whole target population. The Gittins index rule is a powerful tool for sequentially allocating patients to the best treatment based on the responses of patients already treated. However, its application in clinical trials is limited due to technical complexity and lack of randomness. Thompson sampling is an appealing approach, since it makes a compromise between optimal treatment allocation and randomness with some desirable optimal properties in the machine learning context. However, in clinical trial settings, multiple simulation studies have shown disappointing results with Thompson samplers. We consider how to improve short-run performance of Thompson sampling and propose a novel acceleration approach. This approach can also be applied to situations when patients can only be allocated by batch and is very easy to implement without using complex algorithms. A simulation study showed that this approach could improve the performance of Thompson sampling in terms of average total response rate. An application to a redesign of a preference trial to maximize patient's satisfaction is also presented.     

Bayesian hierarchical joint modeling using skew-normal/independent distributions

The multiple longitudinal outcomes collected in many clinical trials are often analyzed by multilevel item response theory (MLIRT) models. The normality assumption for the continuous outcomes in the MLIRT models can be violated due to skewness and/or outliers. Moreover, patients’ follow-up may be stopped by some terminal events (e.g., death or dropout), which are dependent on the multiple longitudinal outcomes. We proposed a joint modeling framework based on the MLIRT model to account for three data features: skewness, outliers, and dependent censoring. Our method development was motivated by a clinical study for Parkinson’s disease.     

网络群体事件政府治理的演化博弈分析

利用演化博弈模型预测舆论的发展趋势,对政府应对网络群体事件采取的治理模式进行了研究.在一般化复制动态模型基础上建立网络群体事件舆论的传播方程,将地方政府部门与弱势群体的策略互动和行为演化融入到传染病传播模型中,用以模拟舆论的扩散和收敛过程.结果表明:在网络群体事件初期,如果弱势群体通过抗争获得政府补偿的概率不断增大,将造成事态的扩大.此时,地方政府应控制信息的交流程度与初始抗争人数,减缓舆论的扩散;在网络群体事件舆论大范围扩散阶段,上级政府介入并采取惩罚措施,及时披露信息,促使网络舆论的收敛平息,实现社会福利最大化.     

Barriers to Managing Coronary Artery Disease Among Older Women

Numerous barriers to managing coronary artery disease (CAD) among older women are reported in the literature; however, few studies adjust for demographic and health status differences. A survey assessing barriers and other factors was distributed to a stratified random sampling of older women with CAD. Factor analysis and multiple logistic regression procedures were used to estimate the impact of these issues on receiving a CAD-related office visit. The most problematic barriers included denial and low health literacy. Efforts to promote patient awareness of heart health and better communication between patients and clinicians may alleviate these barriers.     

Sex differences in the development of mild cognitive impairment and probable Alzheimer’s disease as predicted by hippocampal volume or white matter hyperintensities

This study examined biological sex differences in the development of mild cognitive impairment (MCI) and probable Alzheimer’s disease (AD) development as predicted by changes in the hippocampus or white matter hyperintensities. A secondary data analysis of the National Alzheimer’s Coordinating Center Uniform Data Set was conducted. We selected samples of participants with normal cognition at baseline who progressed to MCI (n = 483) and those who progressed to probable AD (n = 211) to determine if hippocampal volume or white matter hyperintensities (WMH) at baseline predicted progression to probable AD or MCI and whether the rate of progression differed between men and women. The survival analyses indicated that changes in hippocampal volumes affected the progression to probable AD (HR = 0.535, 95% CI [0.300–0.953]) only among women. White men had an increased rate of progression to AD (HR = 4.396, CI [1.012–19.08]; HR = 4.665, 95% CI [1.072–20.29]) compared to men in other race and ethnic groups. Among women, increases in hippocampal volume ratio led to decreased rates of progressing to MCI (HR = 0.386, 95% CI [0.166–0.901]). Increased WMH among men led to faster progression to MCI (HR = 1.048. 95% CI [1.011–1.086]). Women and men who were older at baseline were more likely to progress to MCI. In addition, results from longitudinal analyses showed that women with a higher CDR global score, older age at baseline, or more disinhibition symptoms experienced higher odds of MCI development. Changes in hippocampal volumes affect the progression to or odds of probable AD (and MCI) more so among women than men, while changes in WMH affected the progression to MCI only among men.     

Evidence-Based Programs for Older Adults: A Disconnect Between U.S. National Strategy and Local Senior Center Implementation

While U.S. national policies have been developed to support evidence-based (EB) lifestyle programs for older adults, there has been limited research to determine the extent to which these programs actually reach local communities. This study sought to identify factors that impact the implementation of EB physical activity, nutrition, and chronic disease management programs at regional (Area Agencies on Aging [AAAs]) and community levels (senior Centers [SCs]). Interviews were conducted with directors of four AAAs and 12 SCs to understand their perspectives on EB program implementation. Narratives revealed differences between AAAs and SCs regarding knowledge about EB programs and reasons to promote and adopt these programs. The only agreement occurred when discussing concerns about funding and program inflexibility. Substantial gaps exist between how EB lifestyle programs are promoted and implemented at the regional and community levels.     

Combining QMRA and Epidemiology to Estimate Campylobacteriosis Incidence

The disease burden of pathogens as estimated by QMRA (quantitative microbial risk assessment) and EA (epidemiological analysis) often differs considerably. This is an unsatisfactory situation for policymakers and scientists. We explored methods to obtain a unified estimate using campylobacteriosis in the Netherlands as an example, where previous work resulted in estimates of 4.9 million (QMRA) and 90,600 (EA) cases per year. Using the maximum likelihood approach and considering EA the gold standard, the QMRA model could produce the original EA estimate by adjusting mainly the dose‐infection relationship. Considering QMRA the gold standard, the EA model could produce the original QMRA estimate by adjusting mainly the probability that a gastroenteritis case is caused by Campylobacter. A joint analysis of QMRA and EA data and models assuming identical outcomes, using a frequentist or Bayesian approach (using vague priors), resulted in estimates of 102,000 or 123,000 campylobacteriosis cases per year, respectively. These were close to the original EA estimate, and this will be related to the dissimilarity in data availability. The Bayesian approach further showed that attenuating the condition of equal outcomes immediately resulted in very different estimates of the number of campylobacteriosis cases per year and that using more informative priors had little effect on the results. In conclusion, EA was dominant in estimating the burden of campylobacteriosis in the Netherlands. However, it must be noted that only statistical uncertainties were taken into account here. Taking all, usually difficult to quantify, uncertainties into account might lead to a different conclusion.     

Seclusion,decision-making power,and gender disparities in adult health: Examining hypertension in India

Research on the social determinants of health in developing countries is increasingly focusing on the importance of gender. Cardiovascular conditions such as hypertension are a growing concern in developing countries, where they are now the leading cause of death. Researchers have documented differences in hypertension between men and women, but the importance of gendered practices in shaping these differences has been left unexamined. Using national data from the India Human Development Survey 2005 (N = 101,593), this study assesses the moderating role of two salient and widespread gendered practices—women’s seclusion and decision-making power—on hypertension disparities between women and men. Both seclusion and low decision-making power are associated with increased odds of hypertension for women, but in the case of seclusion reduced hypertension for men. Results also show the gender gap in hypertension is exacerbated with women’s seclusion and low decision-making power.     

A perfect storm: Challenges encountered by family caregivers of persons with Alzheimer’s disease during natural disasters

ABSTRACT

Since Hurricane Katrina there has been a movement across the U.S. to examine best practice for disaster response within the aging population. However, little is known about the experience of natural disasters from the perspective of family caregivers of persons with Alzheimer’s disease and related dementia (ADRD). In this exploratory, qualitative study, family caregivers (n=27) were interviewed about their experience with the historic 2015 South Carolina flood. By using thematic analysis, themes were identified to better understand what unique challenges caregivers of person with ADRD experienced. While many caregivers stated they had experienced a natural disaster previously, none had ever done so in their current caregiving role. The caregiving role affected their ability to prepare for the storm and influenced their decision-making regarding evacuation and utilization of recovery resources. Thus, caregivers were confronted by a “perfect storm” of circumstances and uncertainty. Family caregivers need to have actionable emergency plans for disasters that are specific to their role as caregivers of persons with ADRD. Study implications also suggest the role social work professionals can have in educating, advocating, evaluating, and coordinating support to assist caregivers of persons with ADRD as a potentially vulnerable and at-risk population during all phases of disaster.     

Overcoming the ‘tyranny of the urgent’: integrating gender into disease outbreak preparedness and response

ABSTRACT

This article contributes to discussions on the gender dimensions of disease outbreaks, and preparedness policies and responses, by providing a multi-level analysis of gender-related gaps, particularly illustrating how the failure to challenge gender assumptions and incorporate gender as a priority at the global level has national and local impacts. The implications of neglecting gender dynamics, as well as the potential of equity-based approaches to disease outbreak responses, is illustrated through a case study of the Social Enterprise Network for Development (SEND) Sierra Leone, a non-government organisation (NGO) based in Kailahun, during the Ebola outbreak.