1,721,018 research outputs found
Antiviral treatment for chronic hepatitis C in patients with human immunodeficiency virus.
No full textLactulose, rifaximin or branched chain amino acids for hepatic encephalopathy: what is the evidence?
No full textHepatic encephalopathy (HE) is a serious complication of acute and chronic liver disease associated with severe morbidity and mortality. We performed updated random effects meta-analyses to evaluate the evidence for non-absorbable disaccharides (lactulose and lactitol), rifaximin and branched chain amino acids (BCAA). A meta-analysis of randomized trials showed that, compared with placebo or no intervention, non-absorbable disaccharides have beneficial effects on HE manifestations and prevention of HE episodes. The addition of rifaximin to non-absorbable disaccharides versus rifaximin alone was more beneficial than non-absorbable disaccharides used alone on both outcome measures. Likewise, a meta-analysis of randomised controlled trials found that oral BCAA supplements have beneficial effects on manifestations of HE compared with control supplements. The effect was found in a variety of clinical settings. No convincing effects of intravenous BCAA for episodic HE were identified. In conclusion, evidence-based treatment recommendations for patients with HE should include non-absorbable disaccharides combined with rifaximin or BCAA. Additional evidence is needed to evaluate the effect of combining all three interventions
The Impact of Study Size on Meta-analyses: Examination of Underpowered Studies in Cochrane Reviews
Full text linkBackground: Most meta-analyses include data from one or more small studies that, individually, do not have power to
detect an intervention effect. The relative influence of adequately powered and underpowered studies in published metaanalyses
has not previously been explored. We examine the distribution of power available in studies within meta-analyses
published in Cochrane reviews, and investigate the impact of underpowered studies on meta-analysis results.
Methods and Findings: For 14,886 meta-analyses of binary outcomes from 1,991 Cochrane reviews, we calculated power
per study within each meta-analysis. We defined adequate power as $50% power to detect a 30% relative risk reduction. In
a subset of 1,107 meta-analyses including 5 or more studies with at least two adequately powered and at least one
underpowered, results were compared with and without underpowered studies. In 10,492 (70%) of 14,886 meta-analyses, all
included studies were underpowered; only 2,588 (17%) included at least two adequately powered studies. 34% of the metaanalyses
themselves were adequately powered. The median of summary relative risks was 0.75 across all meta-analyses
(inter-quartile range 0.55 to 0.89). In the subset examined, odds ratios in underpowered studies were 15% lower (95% CI
11% to 18%, P,0.0001) than in adequately powered studies, in meta-analyses of controlled pharmacological trials; and 12%
lower (95% CI 7% to 17%, P,0.0001) in meta-analyses of controlled non-pharmacological trials. The standard error of the
intervention effect increased by a median of 11% (inter-quartile range 21% to 35%) when underpowered studies were
omitted; and between-study heterogeneity tended to decrease.
Conclusions: When at least two adequately powered studies are available in meta-analyses reported by Cochrane reviews,
underpowered studies often contribute little information, and could be left out if a rapid review of the evidence is required.
However, underpowered studies made up the entirety of the evidence in most Cochrane reviews
Oral branched-chain amino acids have a beneficial effect on manifestations of hepatic encephalopathy in a systematic review with meta-analyses of randomized controlled trials.
No full textSupplements with branched-chain amino acid (BCAA) have cerebral, metabolic, and nutritional effects that may benefit patients with hepatic encephalopathy (HE). We therefore conducted a systematic review on the effects of oral BCAAs compared with control supplements or placebo for patients with cirrhosis and recurrent overt or minimal HE. The quantitative analyses included data from 8 trials (n = 382 patients). Individual patient data were retrieved from 4 trials to recalculate outcomes (n = 255 patients). The mean dose of the oral BCAA supplements was 0.25 g/(kg body weight . d). Random effects meta-analysis showed that improvements in HE manifestations were registered for 87 of 172 patients in the BCAA group compared with 56 of 210 controls [risk ratio = 1.71 (95% CI: 1.17, 2.51) number needed to treat = 5 patients]. The effect of BCAAs differed (P = 0.04) for patients with overt [risk ratio = 3.26 (95% CI: 1.47, 7.22)] and minimal HE [risk ratio = 1.32 (95% CI: 0.97, 1.79)]. Subgroup, sensitivity, regression, and sequential analyses found no other sources of heterogeneity or bias. BCAA supplements had no effect on mortality or markers of nutritional status and did not induce adverse events. In conclusion, oral BCAA supplements improve manifestations of HE but have no effect on survival
Diagnostic Performance of a Rapid Magnetic Resonance Imaging Method of Measuring Hepatic Steatosis
Full text linkOBJECTIVES: Hepatic steatosis is associated with an increased risk of developing serious liver disease and other clinical sequelae of the metabolic syndrome. However, visual estimates of steatosis from histological sections of biopsy samples are subjective and reliant on an invasive procedure with associated risks. The aim of this study was to test the ability of a rapid, routinely available, magnetic resonance imaging (MRI) method to diagnose clinically relevant grades of hepatic steatosis in a cohort of patients with diverse liver diseases. MATERIALS AND METHODS: Fifty-nine patients with a range of liver diseases underwent liver biopsy and MRI. Hepatic steatosis was quantified firstly using an opposed-phase, in-phase gradient echo, single breath-hold MRI methodology and secondly, using liver biopsy with visual estimation by a histopathologist and by computer-assisted morphometric image analysis. The area under the receiver operating characteristic (ROC) curve was used to assess the diagnostic performance of the MRI method against the biopsy observations. RESULTS: The MRI approach had high sensitivity and specificity at all hepatic steatosis thresholds. Areas under ROC curves were 0.962, 0.993, and 0.972 at thresholds of 5%, 33%, and 66% liver fat, respectively. MRI measurements were strongly associated with visual (r(2) = 0.83) and computer-assisted morphometric (r(2) = 0.84) estimates of hepatic steatosis from histological specimens. CONCLUSIONS: This MRI approach, using a conventional, rapid, gradient echo method, has high sensitivity and specificity for diagnosing liver fat at all grades of steatosis in a cohort with a range of liver diseases
Media reporting of health interventions: signs of improvement, but major problems persist.
Full text linkBackgroundStudies have persistently shown deficiencies in medical reporting by the mainstream media. We have been monitoring the accuracy and comprehensiveness of medical news reporting in Australia since mid 2004. This analysis of more than 1200 stories in the Australian media compares different types of media outlets and examines reporting trends over time.Methods and findingsBetween March 2004 and June 2008 1230 news stories were rated on a national medical news monitoring web site, Media Doctor Australia. These covered a variety of health interventions ranging from drugs, diagnostic tests and surgery to dietary and complementary therapies. Each story was independently assessed by two reviewers using ten criteria. Scores were expressed as percentages of total assessable items deemed satisfactory according to a coding guide. Analysis of variance was used to compare mean scores and Fishers exact test to compare proportions. Trends over time were analysed using un-weighted linear regression analysis. Broadsheet newspapers had the highest average satisfactory scores: 58% (95% CI 56-60%), compared with tabloid newspapers and online news outlets, 48% (95% CI 44-52) and 48% (95% CI 46-50) respectively. The lowest scores were assigned to stories broadcast by human interest/current affairs television programmes (average score 33% (95% CI 28-38)). While there was a non- significant increase in average scores for all outlets, a significant improvement was seen in the online news media: a rise of 5.1% (95%CI 1.32, 8.97; P 0.009). Statistically significant improvements were seen in coverage of the potential harms of interventions, the availability of treatment or diagnostic options, and accurate quantification of benefits.ConclusionAlthough the overall quality of medical reporting in the general media remains poor, this study showed modest improvements in some areas. However, the most striking finding was the continuing very poor coverage of health news by commercial current affairs television programs
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
Appropriate 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
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