Modelling Cost Effectiveness in Neovascular Age-Related Macular Degeneration: The Impact of Using Contrast Sensitivity vs. Visual Acuity

Background

The cost utility of treatments of age-related macular degeneration (AMD) is commonly assessed using health state transition models defined by levels of visual acuity. However, there is evidence that another measure of visual function, contrast sensitivity, may be better associated with utility than visual acuity. This paper investigates the difference in cost effectiveness resulting from models based on visual acuity and contrast sensitivity using the example of bevacizumab (Avastin) for neovascular AMD. The implications of the choice of outcome on structural uncertainty in the model are investigated.

Method

Health state transition Markov models based on levels of visual acuity and contrast sensitivity are used to represent the costs, health utilities and outcomes of the Avastin for choroidal neovascular age-related macular degeneration (ABC) trial. Health states are associated with costs and utilities based on literature values. Treatment outcomes from the ABC trial are used to predict transitions between states in both models. Total costs and quality-adjusted life-years (QALYs) are calculated for a cohort of patients treated over a defined number of model cycles.

Results

Over a 5-year time horizon, a contrast sensitivity model predicts a statistically significant (p < 0.05) 25 % greater QALY gain than the visual acuity model based on 10,000 Monte Carlo simulations. Bevacizumab is more effective and less costly than the comparator in the contrast sensitivity model and the visual acuity model.

Conclusion

There is considerable structural uncertainty associated with the choice of outcome for modelling the cost effectiveness of AMD treatments. Bevacizumab has a higher incremental QALY gain and more favourable incremental cost-effectiveness ratio when cost effectiveness is assessed using contrast sensitivity outcomes compared with using visual acuity outcomes. Previous cost-effectiveness analyses may have underestimated the cost effectiveness of anti-vascular endothelial growth factor (anti-VEGF) therapy.     

Sex Differences in Response to Visual Sexual Stimuli: A Review

This article reviews what is currently known about how men and women respond to the presentation of visual sexual stimuli. While the assumption that men respond more to visual sexual stimuli is generally empirically supported, previous reports of sex differences are confounded by the variable content of the stimuli presented and measurement techniques. We propose that the cognitive processing stage of responding to sexual stimuli is the first stage in which sex differences occur. The divergence between men and women is proposed to occur at this time, reflected in differences in neural activation, and contribute to previously reported sex differences in downstream peripheral physiological responses and subjective reports of sexual arousal. Additionally, this review discusses factors that may contribute to the variability in sex differences observed in response to visual sexual stimuli. Factors include participant variables, such as hormonal state and socialized sexual attitudes, as well as variables specific to the content presented in the stimuli. Based on the literature reviewed, we conclude that content characteristics may differentially produce higher levels of sexual arousal in men and women. Specifically, men appear more influenced by the sex of the actors depicted in the stimuli while women’s response may differ with the context presented. Sexual motivation, perceived gender role expectations, and sexual attitudes are possible influences. These differences are of practical importance to future research on sexual arousal that aims to use experimental stimuli comparably appealing to men and women and also for general understanding of cognitive sex differences.     

简易近用对比度视力表的设计和临床应用

目的研制一种简易近用对比度视力表,并评估其在视频终端(VDT)视疲劳诊断中的应用价值。方法以新版国家标准对数近视力表为依据,在视标对比度的设计上,除原来的100%对比度外,增加10%对比度及低亮度两项指标。制作完成后,对35名志愿者以连续操作电脑游戏"连连看"的方法诱导视频终端性视疲劳,随后检测视疲劳者前后近对比度视力的变化,以了解该视力表的临床使用情况。结果游戏前后的高亮度100%对比度近视力差异无统计学意义(P>0.05),而游戏后高亮度10%对比度近视力、低亮度近视力均低于游戏前,差异具有统计学意义(P<0.01)。结论简易近用对比度视力表具有检查方便、敏感性高的特点,可应用于VDT视疲劳的临床诊断。     

对比因素对儿童分辨物体细节能力的影响

目的观察对比因素对儿童分辨物体细节能力的影响,了解儿童对比视力的状况。方法使用对比视力表,测量53名裸眼视力≥5.0的正常儿童92%,52%,30%对比水平处的对比视力。结果儿童的对比视力随对比度的降低而显著下降,对比度与视力之间存在显著相关;左、右眼的对比视力差异无统计学意义;男性和女性的对比视力差异无统计学意义。结论低对比的学习环境会增加儿童视觉负荷,在防治学生近视过程中应引起重视。     

MRI增强三期扫描在肺癌非手术治疗疗效评价中的初步研究

目的：初步探讨MRI增强三期扫描在评价周围型肺癌非手术治疗疗效中的作用。方法：对32例周围型肺癌患者行MRI增强三期扫描,分别在25、120、180 s行胸部扫描,记录肺癌增强前后各时相的信号值并计算强化净增值、最大强化率,与文献结果进行对照,记录120、180 s时肺癌的强化模式。结果：治疗后周围型肺癌平扫信号值、增强后120 s及180 s的信号值分别是（478±108）、（926±209）、（1 050±252）。强化净增殖（571±225）、最大强化率（119±49）明显低于文献报道的未经治疗的肺癌强化净增殖（655）（t=2.178,P=0.005〈0.05）及最大强化率（150）（t=4.196,P=0.001〈0.05）。32例中6例在180 s时表现为均匀强化,6例中4例在120 s时表现为不均匀强化,1例表现为均匀强化,1例表现为周边强化。结论：治疗后肺癌有逐渐强化的趋势;MRI增强三期扫描能够反映肺癌的血流动力学信息,是评价肺癌非手术治疗疗效的有效方法。     

造影剂肾病：一个被忽视的并发症

碘造影剂导致过敏反应以及处置已成为临床工作者必须熟悉的医疗常规，但是，造影剂肾病（Contrast induced Nephropathy，CIN）对多数临床工作者而青却较为陌生。不幸的事实是，CIN已成为医院获得性肾病的第三大病因．在使用造影剂的所有人群中，CIN的发生率约1～6％，而在有肾功能不全的患者中高达40～50％。CIN不仅延长了患者的住院时间和增加费用，而且显著地增高了患者的死亡率，尤其那些使用造影剂后需做透析处理的患者，CIN后一年累计死亡率高达45％。     

Non-Celiac Gluten/Wheat Sensitivity: Clinical Characteristics and Microbiota and Mycobiota Composition by Response to the Gluten Challenge Test

The aims of this observational “proof-of-concept” study were to analyze the clinical/psychological characteristics and gut microbiota/mycobiota composition of individuals with suspected non-celiac gluten/wheat sensitivity (NCGS/WS) according to responses to the double-blind-placebo-controlled (DBPC) crossover gluten challenge test. Fifty individuals with suspected NCGS/WS were subjected to the DBPC challenge test; anthropometric measurements, psychometric questionnaires, and fecal samples were collected. Twenty-seven (54%) participants were gluten responsive (NCGS), and 23 were placebo responsive, with an order effect. NCGS individuals displayed a significantly lower risk of eating disorders and a higher mental health score when compared to placebo-responsive participants, confirmed by multiple logistic regression analyses (OR = 0.87; 95% CI 0.76–0.98, p = 0.021, and OR = 1.30; 95% CI 1.06–1.59, p = 0.009, respectively). Principal coordinate analyses based on microbiota composition showed a separation by the DBPC response (p = 0.039). For Bacteroides (p = 0.05) and Parabacteroides (p = 0.007), the frequency of amplicon sequence variants was lower, and that for Blautia (p = 0.009) and Streptococcus (p = 0.004) was higher in NCGS individuals at multiple regression analyses. No difference in the mycobiota composition was detected between the groups. In conclusion, almost half of the individuals with suspected gluten sensitivity reported symptoms with placebo; they showed lower mental health scores, increased risk for eating disorders, and a different gut microbiota composition.