Center for Clinical Trials

Goyang, South Korea

Center for Clinical Trials

Goyang, South Korea
Time filter
Source Type

Chan A.-W.,University of Toronto | Song F.,University of East Anglia | Vickers A.,Sloan Kettering Cancer Center | Jefferson T.,Cochrane Collaboration | And 7 more authors.
The Lancet | Year: 2014

The methods and results of health research are documented in study protocols, full study reports (detailing all analyses), journal reports, and participant-level datasets. However, protocols, full study reports, and participant-level datasets are rarely available, and journal reports are available for only half of all studies and are plagued by selective reporting of methods and results. Furthermore, information provided in study protocols and reports varies in quality and is often incomplete. When full information about studies is inaccessible, billions of dollars in investment are wasted, bias is introduced, and research and care of patients are detrimentally aff ected. To help to improve this situation at a systemic level, three main actions are warranted. First, academic institutions and funders should reward investigators who fully disseminate their research protocols, reports, and participant-level datasets. Second, standards for the content of protocols and full study reports and for data sharing practices should be rigorously developed and adopted for all types of health research. Finally, journals, funders, sponsors, research ethics committees, regulators, and legislators should endorse and enforce policies supporting study registration and wide availability of journal reports, full study reports, and participant-level datasets.

Chalmers I.,James Lind Initiative | Dickersin K.,Center for Clinical Trials
F1000Research | Year: 2013

Stephen Senn challenges Ben Goldacre's assertion in 'Bad Pharma' that biased editorial acceptance of reports with 'positive' findings is not a cause of biased under-reporting of research. We agree with Senn that biased editorial decisions may contribute to reporting bias, but Senn ignores the evidence that biased decisions by researchers to submit reports for possible publication are the main causes of the problem. © 2013 Chalmers I et al.

Holbrook J.T.,Center for Clinical Trials | Wise R.A.,Johns Hopkins University | Gold B.D.,Children's Healthcare Of Atlanta | Blake K.,Nemours Childrens Clinic | And 7 more authors.
JAMA - Journal of the American Medical Association | Year: 2012

Context: Asymptomatic gastroesophageal reflux (GER) is prevalent in children with asthma. Untreated GER has been postulated to be a cause of inadequate asthma control in children despite inhaled corticosteroid treatment, but it is not known whether treatment with proton pump inhibitors improves asthma control. Objective: To determine whether lansoprazole is effective in reducing asthma symptoms in children without overt GER. Design, Setting, and Participants: The Study of Acid Reflux in Children With Asthma, a randomized, masked, placebo-controlled, parallel clinical trial that compared lansoprazole with placebo in children with poor asthma control who were receiving inhaled corticosteroid treatment. Three hundred six participants enrolled from April 2007 to September 2010 at 19 US academic clinical centers were followed up for 24 weeks. A subgroup had an esophageal pH study before randomization. Intervention: Participating children were randomly assigned to receive either lansoprazole, 15 mg/d if weighing less than 30 kg or 30 mg/d if weighing 30 kg or more (n=149), or placebo (n=157). Main Outcome Measures: The primary outcome measure was change in Asthma Control Questionnaire (ACQ) score (range, 0-6; a 0.5-unit change is considered clinically meaningful). Secondary outcome measures included lung function measures, asthma-related quality of life, and episodes of poor asthma control. Results: The mean age was 11 years (SD, 3 years). The mean difference in change (lansoprazole minus placebo) in the ACQ score was 0.2 units (95% CI, 0.0-0.3 units). There were no statistically significant differences in the mean difference in change for the secondary outcomes of forced expiratory volume in the first second (0.0 L; 95% CI, -0.1 to 0.1 L), asthma-related quality of life (-0.1; 95% CI, -0.3 to 0.1), or rate of episodes of poor asthma control (relative risk, 1.2; 95% CI, 0.9-1.5). Among the 115 children with esophageal pH studies, the prevalence of GER was 43%. In the subgroup with a positive pH study, no treatment effect for lansoprazole vs placebo was observed for any asthma outcome. Children treated with lansoprazole reported more respiratory infections (relative risk, 1.3 [95% CI, 1.1-1.6]). Conclusion: In this trial of children with poorly controlled asthma without symptoms of GER who were using inhaled corticosteroids, the addition of lansoprazole, compared with placebo, improved neither symptoms nor lung function but was associated with increased adverse events. Trial Registration: Identifier: NCT00442013. ©2012 American Medical Association. All rights reserved.

Nam S.Y.,Center for Cancer Prevention and Detection | Choi I.J.,Research Institute and Hospital | Ryu K.H.,Center for Cancer Prevention and Detection | Kim B.C.,Center for Cancer Prevention and Detection | And 2 more authors.
American Journal of Gastroenterology | Year: 2010

Objectives: We evaluated the association between current Helicobacter pylori infection and reflux esophagitis and the effect of H. pylori eradication on reflux esophagitis in a healthy screening population. Methods: A total of 10,102 subjects in a comprehensive screening cohort were enrolled, and 4,007 subjects had follow-up after a median of 2 years. Effects of H. pylori infection on reflux esophagitis were estimated with odds ratios (ORs) and 95% confidence intervals (CIs) using multiple logistic regression analysis. We evaluated the change in prevalence of reflux esophagitis and reflux symptoms after H. pylori eradication vs. persistence. Results: The prevalence of reflux esophagitis (as classified by the Los Angeles system) was 4.9% (490/10,102). Whereas the prevalence of reflux esophagitis was 6.4% (319/4,971) in subjects without H. pylori infection, it was 3.3% (171/5,131) in subjects with infection (P=0.001). H. pylori infection had a strong negative association with reflux esophagitis in multivariate analysis (OR 0.42; 95% CI, 0.34-0.51). Compared with the prevalence of reflux esophagitis in the persistent infection group, the prevalence of reflux esophagitis increased after successful H. pylori eradication (OR 2.34; 95% CI, 1.45-3.76; P=0.001), which was comparable to that of the H. pylori-negative group (OR 2.42; 95% CI, 1.73-3.36; P=0.001). However, reflux symptoms had no association with H. pylori infection or eradication. Conclusions: In a healthy screening population, H. pylori infection had a strong negative association with reflux esophagitis, but H. pylori eradication increased the prevalence of erosive esophagitis to the level of H. pylori-negative individuals. Long-term clinical significance of newly developed erosive esophagitis after H. pylori eradication should be evaluated prospectively. © 2010 by the American College of Gastroenterology.

Mosbech H.,Copenhagen University | Deckelmann R.,Center for Clinical Trials | De Blay F.,University of Strasbourg | Pastorello E.A.,Ospedale Niguarda Ca Granda | And 3 more authors.
Journal of Allergy and Clinical Immunology | Year: 2014

Background Investigations meeting current standards are limited for the effect of house dust mite (HDM) allergy immunotherapy in asthmatic patients. Objective This trial investigated the efficacy and safety of a standardized quality (SQ; allergen standardization method proprietary to the trial sponsor) HDM SLIT-tablet (ALK, Hørsholm, Denmark) in adults and adolescents with HDM respiratory allergic disease. This publication reports the results of the endpoints related to asthma. Methods Six hundred four subjects 14 years or older with HDM allergic rhinitis and mild-to-moderate asthma were randomized 1:1:1:1 to double-blind daily treatment with one of 3 active doses (1, 3, or 6 SQ-HDM) or placebo. Their use of inhaled corticosteroid (ICS) was standardized and adjusted at baseline and the end of treatment to the lowest dose providing asthma control. The primary end point was a reduction in ICS dose from the individual subject's baseline dose after 1 year of treatment. Results The primary analysis revealed a mean difference between 6 SQ-HDM and placebo in the reduction in daily ICS dose of 81 μg (P =.004). Relative mean and median reductions were 42% and 50% for 6 SQ-HDM and 15% and 25% for placebo, respectively. No statistically significant differences were observed for the other assessed asthma parameters, reflecting the intended controlled status of the trial subjects. The most common adverse events were local reactions in the mouth. The rate and severity of adverse events were higher for 3 and 6 SQ-HDM than for 1 SQ-HDM and placebo. Conclusion Efficacy in mild-to-moderate asthma of 6 SQ-HDM relative to placebo was demonstrated by a moderate statistically significant reduction in the ICS dose required to maintain asthma control. All active doses were well tolerated. © 2014 The Authors. Published by Elsevier Inc.

Nam S.Y.,Center for Cancer Prevention and Detection | Choi I.J.,Center for Gastric Cancer | Ryu K.H.,Center for Cancer Prevention and Detection | Park B.J.,Center for Cancer Prevention and Detection | And 2 more authors.
Gastroenterology | Year: 2010

Background & Aims Data on the association between erosive esophagitis and obesity are inconsistent because of variations in study populations and methods used to determine obesity. Methods Participants in a prospective health-screening cohort underwent esophagogastroduodenoscopy and computed tomography. The association between erosive esophagitis and obesity (measured by body mass index [BMI], waist circumference, and abdominal visceral adipose tissue volume) was estimated with odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for confounding factors. We also analyzed the association between obesity and erosive esophagitis by sex. Results The prevalence of erosive esophagitis was 9.3% (495/5329). The OR for erosive esophagitis correlated with obesity measured by BMI, waist circumference, and abdominal visceral adipose tissue volume (P < .001 for each factor). The multivariate OR for erosive esophagitis was 1.97 (95% CI: 1.342.90) for a visceral adipose tissue volume of 500999 cm3, 2.27 (95% CI: 1.513.39) for 10001499 cm3, and 2.94 (95% CI: 1.874.62) for <1500 cm3, compared with participants who had visceral adipose tissue volumes less than 500 cm3. When measures of obesity were analyzed simultaneously, abdominal visceral adipose tissue volume, but not BMI or waist circumference, was associated with erosive esophagitis. The 3 measures of obesity were significantly associated with erosive esophagitis in males, but only visceral adipose tissue volume was associated with erosive esophagitis in females (P = .002). Conclusions In contrast to BMI or waist circumference, abdominal visceral adipose tissue volume is associated with an increased risk of erosive esophagitis in males and females. © 2010 AGA Institute.

Akpek E.K.,Wilmer Eye Institute | Lindsley K.B.,Center for Clinical Trials | Adyanthaya R.S.,Wilmer Eye Institute | Swamy R.,Wilmer Eye Institute | And 2 more authors.
Ophthalmology | Year: 2011

Background: Outcomes-based review of reported treatment options for patients with dry eye secondary to Sjögren's syndrome (SS). Clinical Relevance: Dry eye affects many individuals worldwide. Significant proportion of patients with dry eye has underlying SS, a progressive autoimmune condition. The few suggested guidelines for the treatment of dry eye are mostly based on severity of symptoms and/or clinical findings rather than on outcomes analysis, and do not differentiate SS from other causes of dry eye. Methods and Literature Review: A search strategy was developed to identify prospective, interventional studies of treatments for SS-associated dry eye from electronic databases. Eligible references were restricted to English-language articles published after 1975. These sources were augmented by hand searches of reference lists from accessed articles. Study selection, data extraction, and grading of evidence were completed independently by <4 review authors. Results: The searches identified 3559 references as of August 10, 2010. After duplicate review of the titles and abstracts, 245 full-text papers were assessed, 62 of which were relevant for inclusion in the review. Conclusions: In the current literature on SS-associated dry eye, there is a paucity of rigorous clinical trials to support therapy recommendations. Nonetheless, the recommended treatments include topical lubricants, topical anti-inflammatory therapy, and tear-conserving strategies. The efficacy of oral secretagogues seems greater in the treatment of oral dryness than ocular dryness. Although oral hydroxychloroquine is commonly prescribed to patients with SS to alleviate fatigue and arthralgias, the literature lacks strong evidence for the efficacy of this treatment for dry eye. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. © 2011 American Academy of Ophthalmology.

Li T.,Center for Clinical Trials | Dickersin K.,Center for Clinical Trials
Ophthalmology | Year: 2013

Clinical relevance: Systematic reviews and meta-analyses serve as a basis for decision-making and clinical practice guidelines and should be carried out using appropriate methodology to avoid incorrect inferences. Topic: We describe the characteristics, statistical methods used for meta-analyses, and citation patterns of all 21 glaucoma systematic reviews we identified pertaining to the effectiveness of prostaglandin analog eye drops in treating primary open-angle glaucoma, published between December 2000 and February 2012. Methods: We abstracted data, assessed whether appropriate statistical methods were applied in meta-analyses, and examined citation patterns of included reviews. Results: We identified two forms of problematic statistical analyses in 9 of the 21 systematic reviews examined. Except in 1 case, none of the 9 reviews that used incorrect statistical methods cited a previously published review that used appropriate methods. Reviews that used incorrect methods were cited 2.6 times more often than reviews that used appropriate statistical methods. We speculate that by emulating the statistical methodology of previous systematic reviews, systematic review authors may have perpetuated incorrect approaches to meta-analysis. Conclusions: The use of incorrect statistical methods, perhaps through emulating methods described in previous research, calls conclusions of systematic reviews into question and may lead to inappropriate patient care. We urge systematic review authors and journal editors to seek the advice of experienced statisticians before undertaking or accepting for publication a systematic review and meta-analysis. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. © 2013 American Academy of Ophthalmology.

Lindsley K.,Center for Clinical Trials
Cochrane database of systematic reviews (Online) | Year: 2012

Blepharitis, an inflammatory condition associated with itchiness, redness, flaking, and crusting of the eyelids, is a common eye condition that affects both children and adults. It is common in all ethnic groups and across all ages. Although infrequent, blepharitis can lead to permanent alterations to the eyelid margin or vision loss from superficial keratopathy (abnormality of the cornea), corneal neovascularization, and ulceration. Most importantly, blepharitis frequently causes significant ocular symptoms such as burning sensation, irritation, tearing, and red eyes as well as visual problems such as photophobia and blurred vision. The exact etiopathogenesis is unknown, but suspected to be multifactorial, including chronic low-grade infections of the ocular surface with bacteria, infestations with certain parasites such as demodex, and inflammatory skin conditions such as atopy and seborrhea. Blepharitis can be categorized in several different ways. First, categorization is based on the length of disease process: acute or chronic blepharitis. Second, categorization is based on the anatomical location of disease: anterior, or front of the eye (e.g. staphylococcal and seborrheic blepharitis), and posterior, or back of the eye (e.g. meibomian gland dysfunction (MGD)). This review focuses on chronic blepharitis and stratifies anterior and posterior blepharitis. To examine the effectiveness of interventions in the treatment of chronic blepharitis. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 1), MEDLINE (January 1950 to February 2012), EMBASE (January 1980 to February 2012), the metaRegister of Controlled Trials (mRCT) (, ( and the WHO International Clinical Trials Registry Platform (ICTRP) ( We searched the reference lists of included studies for any additional studies not identified by the electronic searches. There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 9 February 2012. We included randomized controlled trials (RCTs) and quasi-randomized controlled trials (CCTs) in which participants were adults aged 16 years or older and clinically diagnosed with chronic blepharitis. We also included trials where participants with chronic blepharitis were a subset of the participants included in the study and data were reported separately for these participants. Interventions within the scope of this review included medical treatment and lid hygiene measures. Two authors independently assessed search results, reviewed full-text copies for eligibility, examined risk of bias, and extracted data. Data were meta-analyzed for studies comparing similar interventions and reporting comparable outcomes with the same timing. Otherwise, results for included studies were summarized in the text. There were 34 studies (2169 participants with blepharitis) included in this review: 20 studies (14 RCTs and 6 CCTs) included 1661 participants with anterior or mixed blepharitis and 14 studies (12 RCTs and 2 CCTs) included 508 participants with posterior blepharitis (MGD). Due to the heterogeneity of study characteristics among the included studies, with respect to follow-up periods and types of interventions, comparisons, and condition of participants, our ability to perform meta-analyses was limited. Topical antibiotics were shown to provide some symptomatic relief and were effective in eradicating bacteria from the eyelid margin for anterior blepharitis. Lid hygiene may provide symptomatic relief for anterior and posterior blepharitis. The effectiveness of other treatments for blepharitis, such as topical steroids and oral antibiotics, were inconclusive. Despite identifying 34 trials related to treatments for blepharitis, there is no strong evidence for any of the treatments in terms of curing chronic blepharitis. Commercial products are marketed to consumers and prescribed to patients without substantial evidence of effectiveness. Further research is needed to evaluate the effectiveness of such treatments. Any RCT designed for this purpose should separate participants by type of condition (e.g. staphylococcal blepharitis or MGD) in order to minimize imbalances between groups (type I errors) and to achieve statistical power for analyses (prevent type II errors). Medical interventions and commercial products should be compared with conventional lid hygiene measures, such as warm compresses and eyelid margin washing, to determine effectiveness, as well as head-to-head to show comparative effectiveness between treatments. Outcomes of interest should be patient-centered and measured using validated questionnaires or scales. It is important that participants be followed long-term, at least one year, to assess chronic outcomes properly.

Li T.,Center for Clinical Trials | Vedula S.S.,Center for Clinical Trials | Scherer R.,Center for Clinical Trials | Dickersin K.,Center for Clinical Trials
Annals of Internal Medicine | Year: 2012

The authors developed and tested a framework for identifying evidence gaps and prioritizing comparative effectiveness research by using a combination of clinical practice guidelines and systematic reviews. In phase 1 of the project, reported elsewhere, 45 clinical questions on the management of primary open-angle glaucoma were derived from practice guidelines and prioritized by using a 2-round Delphi survey of clinicians. On the basis of the clinicians' responses, 9 questions were classified as high-priority. In phase 2, reported here, systematic reviews that addressed the 45 clinical questions were identified. The reviews were classified as at low, high, or unclear risk of bias, and evidence gaps (in which no systematic review was at low risk of bias) were identified. The following comparative effectiveness research agenda is proposed: Two of the 9 high-priority questions require new primary research (such as a randomized, controlled trial) and 4 require a new systematic review. The utility and limitations of the framework and future adaptations are discussed. © 2012 American College of Physicians.

Loading Center for Clinical Trials collaborators
Loading Center for Clinical Trials collaborators