Barrett's esophagus and its association with hiatal hernia, cigarette smoking and colonic tumors

Introduction and Aims Barrett's esophagus (BE) is a premalignant condition to esophageal adenocarcinoma involving metaplasia of the esophageal epithelium. Since BE was first identified and described, it has been closely associated with hiatal hernia. The strength of the relationship has never been quantified, nor has the association, adjusted for confounders such as obesity and reflux, been examined. Male gender, obesity and reflux are well recognized risk factors for BE, however it is less certain what role environmental factors such as cigarette smoking play in the development of the condition. The association of BE with colonic tumors has also been speculated on but not clearly established. The aim of this thesis was to further explore the epidemiology of BE, specifically the relationship between BE and hiatal hernia, cigarette smoking and colonic tumors, through meta-analyses. Methods Three meta-analyses and systematic reviews were conducted, quantifying the relationship between BE and hiatal hernia, cigarette smoking and colonic tumors, respectively. Four electronic databases (Medline, PubMed, Embase, and Current Contents Connect) were searched for observational studies of BE patients. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random effects model for the association BE with hiatal hernia, cigarette smoking and colonic tumors. Results A positive relationship was observed between BE and hiatal hernia, which remained even after adjusting for reflux. Cigarette smoking was associated with an increased risk of BE. This was reflected in subgroup analyses of ever-, current- and former-smokers. BE was also associated with colonic tumors. The relationship was observed with both benign adenomatous tumors as well as with colorectal cancer, though it was stronger for colorectal cancer. Conclusions The association between BE and hiatal hernia is stronger for long segment BE when compared with short segment BE, and it appears to be independent of reflux. BE patients are also more likely to have ever smoked cigarettes. BE is associated with colonic tumors, with the association being stronger with colorectal cancer than with benign lesions

TECH-VER: A Verification Checklist to Reduce Errors in Models and Improve Their Credibility

Background In health economic literature, checklists or best practice recommendations on model validation/credibility always declare verifcation of the programmed model as a fundamental step, such as ‘is the model implemented correctly and does the implementation accurately represent the conceptual model?’ However, to date, little operational guidance for the model verifcation process has been given. In this study, we aimed to create an operational checklist for model users or reviewers to verify the technical implementation of health economic decision analytical models and document their verifcation eforts. Methods Literature on model validation, verifcation, programming errors and credibility was reviewed systematically from scientifc databases. An initial beta version of the checklist was developed based on the checklists/tests identifed from the literature and from authors’ previous modeling/appraisa

ARE DISEASE MANAGEMENT PROGRAMS FOR COPD COST-SAVING?

Prevention, Population and Disease management (PrePoD

Discrete choice experiment versus swing-weighting:A head-to-head comparison of diabetic patient preferences for glucose-monitoring devices

Introduction Limited evidence exists for how patient preference elicitation methods compare directly. This study compares a discrete choice experiment (DCE) and swing-weighting (SW) by eliciting preferences for glucose-monitoring devices in a population of diabetes patients. Methods A sample of Dutch adults with type 1 or 2 diabetes (n = 459) completed an online survey assessing their preferences for glucose-monitoring devices, consisting of both a DCE and a SW exercise. Half the sample completed the DCE first; the other half completed the SW first. For the DCE, the relative importance of the attributes of the devices was determined using a mixed-logit model. For the SW, the relative importance of the attributes was based on ranks and points allocated to the ‘swing’ from the worst to the best level of the attribute. The preference outcomes and self-reported response burden were directly compared between the two methods. Results Participants reported they perceived the DCE to be easier to understand and answer compared to the SW. Both methods revealed that cost and precision of the device were the most important attributes. However, the DCE had a 14.9-fold difference between the most and least important attribute, while the SW had a 1.4-fold difference. The weights derived from the SW were almost evenly distributed between all attributes. Conclusions The DCE was better received by participants, and generated larger weight differences between each attribute level, making it the more informative method in our case study. This method comparison provides further evidence of the degree of method suitability and trustworthiness.</p