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- Axfors, Cathrine, et al.
(författare)
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Association between convalescent plasma treatment and mortality in COVID-19 : a collaborative systematic review and meta-analysis of randomized clinical trials
- 2021
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Ingår i: BMC Infectious Diseases. - : BioMed Central (BMC). - 1471-2334. ; 21:1
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Forskningsöversikt (refereegranskat)abstract
- Background: Convalescent plasma has been widely used to treat COVID-19 and is under investigation in numerous randomized clinical trials, but results are publicly available only for a small number of trials. The objective of this study was to assess the benefits of convalescent plasma treatment compared to placebo or no treatment and all-cause mortality in patients with COVID-19, using data from all available randomized clinical trials, including unpublished and ongoing trials (Open Science Framework, ). Methods: In this collaborative systematic review and meta-analysis, clinical trial registries (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform), the Cochrane COVID-19 register, the LOVE database, and PubMed were searched until April 8, 2021. Investigators of trials registered by March 1, 2021, without published results were contacted via email. Eligible were ongoing, discontinued and completed randomized clinical trials that compared convalescent plasma with placebo or no treatment in COVID-19 patients, regardless of setting or treatment schedule. Aggregated mortality data were extracted from publications or provided by investigators of unpublished trials and combined using the Hartung-Knapp-Sidik-Jonkman random effects model. We investigated the contribution of unpublished trials to the overall evidence. Results: A total of 16,477 patients were included in 33 trials (20 unpublished with 3190 patients, 13 published with 13,287 patients). 32 trials enrolled only hospitalized patients (including 3 with only intensive care unit patients). Risk of bias was low for 29/33 trials. Of 8495 patients who received convalescent plasma, 1997 died (23%), and of 7982 control patients, 1952 died (24%). The combined risk ratio for all-cause mortality was 0.97 (95% confidence interval: 0.92; 1.02) with between-study heterogeneity not beyond chance (I-2 = 0%). The RECOVERY trial had 69.8% and the unpublished evidence 25.3% of the weight in the meta-analysis. Conclusions: Convalescent plasma treatment of patients with COVID-19 did not reduce all-cause mortality. These results provide strong evidence that convalescent plasma treatment for patients with COVID-19 should not be used outside of randomized trials. Evidence synthesis from collaborations among trial investigators can inform both evidence generation and evidence application in patient care.
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| 2. |
- Hampton, Stephanie E., et al.
(författare)
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Ecology under lake ice
- 2017
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 20:1, s. 98-111
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Forskningsöversikt (refereegranskat)abstract
- Winter conditions are rapidly changing in temperate ecosystems, particularly for those that experience periods of snow and ice cover. Relatively little is known of winter ecology in these systems, due to a historical research focus on summer ‘growing seasons’. We executed the first global quantitative synthesis on under-ice lake ecology, including 36 abiotic and biotic variables from 42 research groups and 101 lakes, examining seasonal differences and connections as well as how seasonal differences vary with geophysical factors. Plankton were more abundant under ice than expected; mean winter values were 43.2% of summer values for chlorophyll a, 15.8% of summer phytoplankton biovolume and 25.3% of summer zooplankton density. Dissolved nitrogen concentrations were typically higher during winter, and these differences were exaggerated in smaller lakes. Lake size also influenced winter-summer patterns for dissolved organic carbon (DOC), with higher winter DOC in smaller lakes. At coarse levels of taxonomic aggregation, phytoplankton and zooplankton community composition showed few systematic differences between seasons, although literature suggests that seasonal differences are frequently lake-specific, species-specific, or occur at the level of functional group. Within the subset of lakes that had longer time series, winter influenced the subsequent summer for some nutrient variables and zooplankton biomass.
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| 3. |
- Boehmer, John P, et al.
(författare)
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Adjudication of mortality events in a heart failure-arrhythmia trial by a multiparameter descriptive method: comparison with methods used in heart failure trials and methods used in arrhythmia trials.
- 2008
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Ingår i: Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing. - : Springer Science and Business Media LLC. - 1383-875X. ; 23:2, s. 101-10
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Mortality events in studies of cardiovascular disease are currently adjudicated using different methodologies depending on the investigators' preferences. Traditionally, deaths have been categorized by a single term, such as sudden, ischemic, or pump failure, a method that can be referred to as "categorical". In contrast, deaths may be categorized using several specific pieces of information about the event, a method that can be referred to as "multiparameter descriptive." Herein, we describe an adaptation of this descriptive method in a trial of patients with heart failure and arrhythmias. METHODS AND RESULTS: Case examples were selected from two clinical trials of an investigational implantable cardioverter-defibrillator (ICD)-biventricular pacing system in patients with symptomatic heart failure and a class I indication for ICD implantation, and the complete results for one of the trials are given. Deaths were classified according to the new descriptive method, and also according to published categorical methods for heart failure and arrhythmia trials. The descriptive method preserved traditional arrhythmia and heart failure trial single category classifications of death. Furthermore, there was agreement between the arrhythmia and heart failure category classifications in 126 of the 148 of the mortality events adjudicated (85%). CONCLUSION: A descriptive method for the classification of death retains more data and allows for comparison among trials using different classification schemes. This may allow greater mechanistic insight into study populations that have diverse and frequently multiple etiologies of death.
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