1,721,007 research outputs found
Calcium supplementation for the prevention of colorectal adenomas: a systematic review and meta-analysis of randomized controlled trials
No full textAIM: To determine the efficacy of calcium supplementation in reducing the recurrence of colorectal adenomas. " METHODS: We conducted a systematic review and meta-analysis of published studies. We searched PubMed, Scopus, the Cochrane Library, the WHO International Clinical Trials Registry Platform, and the ClinicalTrials. gov website, through December 2015. Randomized, placebo-controlled trials assessing supplemental calcium intake for the prevention of recurrence of adenomas were eligible for inclusion. Two reviewers independently selected studies based on predefined criteria, extracted data and outcomes (recurrence of colorectal adenomas, and advanced or ""high-risk"" adenomas), and rated each trial's risk-of-bias. Between-study heterogeneity was assessed, and pooled risk ratio (RR) estimates with their 95% confidence intervals (95% CI) were calculated using fixed-and random-effects models. To express the treatment effect in clinical terms, we calculated the number needed to treat (NNT) to prevent one adenoma recurrence. We also assessed the quality of evidence using GRADE." RESULTS: Four randomized, placebo-controlled trials met the eligibility criteria and were included. Daily doses of elemental calcium ranged from 1200 to 2000 mg, while the duration of treatment and follow-up of participants ranged from 36 to 60 mo. Synthesis of intention-to-treat data, for participants who had undergone follow-up colonoscopies, indicated a modest protective effect of calcium in prevention of adenomas (fixed-effects, RR = 0.89, 95% CI: 0.82-0.96 random-effects, RR = 0.87, 95% CI: 0.77-0.98 high quality of evidence). The NNT was 20 (95% CI: 12-61) to prevent one colorectal adenoma recurrence within a period of 3 to 5 years. On the other hand, the association between calcium treatment and advanced adenomas did not reach statistical significance (fixed-effects, RR = 0.92, 95% CI: 0.75-1.13 random-effects, RR = 0.92, 95% CI: 0.71-1.18 moderate quality of evidence). CONCLUSION: Our results suggest a modest chemo-preventive effect of calcium supplements against recurrent colorectal adenomas over a period of 36 to 60 mo. Further research is warranted.AIM: To determine the efficacy of calcium supplementation in reducing the recurrence of colorectal adenomas. METHODS: We conducted a systematic review and meta-analysis of published studies. We searched PubMed, Scopus, the Cochrane Library, the WHO International Clinical Trials Registry Platform, and the ClinicalTrials.gov website, through December 2015. Randomized, placebo-controlled trials assessing supplemental calcium intake for the prevention of recurrence of adenomas were eligible for inclusion. Two reviewers independently selected studies based on predefined criteria, extracted data and outcomes (recurrence of colorectal adenomas, and advanced or "high-risk" adenomas), and rated each trial's riskof- bias. Between-study heterogeneity was assessed, and pooled risk ratio (RR) estimates with their 95% confidence intervals (95%CI) were calculated using fixed- and random-effects models. To express the treatment effect in clinical terms, we calculated the number needed to treat (NNT) to prevent one adenoma recurrence. We also assessed the quality of evidence using GRADE. RESULTS: Four randomized, placebo-controlled trials met the eligibility criteria and were included. Daily doses of elemental calcium ranged from 1200 to 2000 mg, while the duration of treatment and follow-up of participants ranged from 36 to 60 mo. Synthesis of intention-to-treat data, for participants who had undergone follow-up colonoscopies, indicated a modest protective effect of calcium in prevention of adenomas (fixed-effects, RR = 0.89, 95%CI: 0.82-0.96; randomeffects, RR = 0.87, 95%CI: 0.77-0.98; high quality of evidence). The NNT was 20 (95%CI: 12-61) to prevent one colorectal adenoma recurrence within a period of 3 to 5 years. On the other hand, the association between calcium treatment and advanced adenomas did not reach statistical significance (fixed-effects, RR = 0.92, 95%CI: 0.75-1.13; random-effects, RR = 0.92, 95%CI: 0.71-1.18; moderate quality of evidence). CONCLUSION: Our results suggest a modest chemopreventive effect of calcium supplements against recurrent colorectal adenomas over a period of 36 to 60 mo. Further research is warranted
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Environmental Risk Factors for Inflammatory Bowel Diseases: An Umbrella Review of Meta-analyses
No full textAppropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Systematic review with meta-analysis: use of 5-aminosalicylates and risk of colorectal neoplasia in patients with inflammatory bowel disease
No full textBackgroundThe relationship of 5-aminosalicylates' use with the risk of colorectal neoplasia in patients with inflammatory bowel disease (IBD) has been the focus of a growing body of research. AimTo investigate this association through an updated meta-analysis of observational studies. MethodsPubMed, Scopus and major conference proceedings were searched up to December 2016. The identified studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates were calculated using random-effect models. Detailed subgroup analyses were performed. The GRADE approach was used to assess the quality of evidence. ResultsThirty-one independent observational studies including 2137 cases of colorectal neoplasia (of which 76% were cancers) were incorporated. Between-study heterogeneity was moderate, while strong suspicion of small-study effects was raised. The overall analysis revealed a protective association between 5-aminosalicylates' use and colorectal neoplasia (RR=0.57, 95% CI: 0.45-0.71). When the analysis was stratified according to study design and setting, the association was significant in cohort (RR=0.65, 95% CI: 0.43-0.99 n=10) and case-control studies (RR=0.53, 95% CI: 0.40-0.70 n=21), population-based (RR=0.70, 95% CI: 0.52-0.94 n=12) and hospital-based studies (RR=0.46, 95% CI: 0.34-0.61 n=19). Exposure to 5-aminosalicylates was protective against cancer (RR=0.58, 95% CI: 0.45-0.74) and dysplasia (RR=0.54, 95% CI: 0.35-0.84). The reduction in colorectal neoplasia risk was strong in ulcerative colitis (RR=0.50, 95% CI: 0.38-0.64), but nonsignificant in Crohn's disease (RR=0.76, 95% CI: 0.43-1.33). Mesalazine (mesalamine) use was protective (RR=0.70, 95% CI: 0.51-0.94) with evidence of a dose-effect. The effect of sulfasalazine was marginally nonsignificant (RR=0.72, 95% CI: 0.51-1.01). ConclusionsOur findings support a potential chemopreventive role of 5-aminosalicylates in IBD. Further, high-quality prospective research is warranted
Intravenous Versus Oral Iron for the Treatment of Anemia in Inflammatory Bowel Disease A Systematic Review and Meta-Analysis of Randomized Controlled Trials
No full textAnemia is the most prevalent extraintestinal complication of inflammatory bowel disease (IBD). Our aim was to evaluate the comparative efficacy and harm of intravenous (IV) versus oral iron supplementation for correcting anemia in adult IBD patients. We conducted a systematic review and meta-analysis to integrate evidence from randomized controlled trials having enrolled adults with IBD, and comparing IV versus oral iron (head-to-head) for correcting iron-deficiency anemia. Medline, Embase, Scopus, and the Web of Science database were searched through July 2015. The Cochrane Central Register of Controlled Trials, the WHO International Clinical Trials Registry Platform, the ClinicalTrials.gov, and international conference proceedings were also investigated. Two reviewers independently abstracted study data and outcomes, and rated each trial's risk-of-bias. Pooled odds ratio (OR) estimates with their 95% CIs were calculated using fixed- and random-effects models. Five eligible studies, including 694 IBD patients, were identified. In meta-analysis, IV iron demonstrated a higher efficacy in achieving a hemoglobin rise of >= 2.0 g/dL as compared to oral iron (OR: 1.57, 95% CI: 1.13, 2.18). Treatment discontinuation rates, due to adverse events or intolerance, were lower in the IV iron groups (OR: 0.27, 95% CI: 0.13, 0.59). Similarly, the occurrence of gastrointestinal adverse events was consistently lower in the IV iron groups. On the contrary, serious adverse events (SAEs) were more frequently reported among patients receiving IV iron preparations (OR: 4.57, 95% CI: 1.11, 18.8) however, the majority of the reported SAEs were judged as unrelated or unlikely to be related to the study medication. We found no evidence of publication bias, or between-study heterogeneity, across all analyses. Risk of bias was high across primary studies, because patients and personnel were not blinded to the intervention. IV iron appears to be more effective and better tolerated than oral iron for the treatment of IBD-associated anemia
Editorial: evidence is growing for protective effects of 5-aminosalicylates against colitis-associated cancer-authors' reply
No full textBiologic Therapies and Risk of Infection and Malignancy in Patients With Inflammatory Bowel Disease: A Systematic Review and Network Meta-analysis
No full textBACKGROUND & AIMS: Safety issues are a major concern for patients considering treatments for inflammatory bowel disease (IBD). We performed a systematic review and meta-analysis to determine whether biologic agents affect the risk of infection or malignancy in adults with IBD. METHODS: We searched PubMed, Embase, Scopus, Cochrane IBD Group Specialized Trials Register, World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials. gov through March 2016 for randomized placebo-controlled or head-to-head trials of biologic agents approved for treatment of adults with IBD (ie, adalimumab, certolizumab, golimumab, infliximab, natalizumab, or vedolizumab). Two reviewers independently extracted study data and outcomes (serious infections, opportunistic infections, tuberculosis, any infection, and malignancies) and rated each trial's risk of bias. We used conventional meta-analysis to synthesize direct evidence and a network meta-analysis for adjusted indirect treatment comparisons. RESULTS: We identified 49 randomized placebo-controlled studies comprising 14,590 participants. Synthesis of the evidence indicated that patients treated with biologics had a moderate increase in risk of any infection (odds ratio [OR], 1.19 95% confidence interval [CI], 1.10-1.29) and a significant increase in risk of opportunistic infections (OR, 1.90 95% CI, 1.21-3.01). Risk of serious infections was not increased in patients treated with biologics (OR, 0.89 95% CI, 0.71-1.12). On the contrary, biologics appeared to significantly reduce risk of serious infections in studies with low risk of bias (OR, 0.56 95% CI, 0.35-0.90). We did not find an increased risk of malignancy with use of biologic agents (OR, 0.90 95% CI, 0.54-1.50), but data were insufficient in terms of exposure and follow-up times. None of the indirect comparisons, either among the individual agents or between the antitumor necrosis factor and anti-integrin classes, reached significance for any of the outcomes analyzed. CONCLUSIONS: On the basis of a systematic review and meta-analysis, biologic agents increase the risk of opportunistic infections in patients with IBD, but not the risk of serious infections. It is necessary to continue to monitor the comparative and long-term safety profiles of these drugs
- …
