179 research outputs found

    Cluster over individual randomization: are study design choices appropriately justified? Review of a random sample of trials

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    Taljaard, M., Goldstein, C. E., Giraudeau, B., Nicholls, S. G., Carroll, K., Hey, S. P., … Weijer, C. (2020). Cluster over individual randomization: are study design choices appropriately justified? Review of a random sample of trials. Clinical Trials. Copyright © The Author(s), 2020. DOI: https://doi.org/10.1177/174077451989679

    Electronic search strategies to identify reports of cluster randomized trials in MEDLINE: low precision will improve with adherence to reporting standards

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    BACKGROUND: Cluster randomized trials (CRTs) present unique methodological and ethical challenges. Researchers conducting systematic reviews of CRTs (e.g., addressing methodological or ethical issues) require efficient electronic search strategies (filters or hedges) to identify trials in electronic databases such as MEDLINE. According to the CONSORT statement extension to CRTs, the clustered design should be clearly identified in titles or abstracts; however, variability in terminology may make electronic identification challenging. Our objectives were to (a) evaluate sensitivity ( recall ) and precision of a well-known electronic search strategy ( randomized controlled trial as publication type) with respect to identifying CRTs, (b) evaluate the feasibility of new search strategies targeted specifically at CRTs, and (c) determine whether CRTs are appropriately identified in titles or abstracts of reports and whether there has been improvement over time. METHODS: We manually examined a wide range of health journals to identify a gold standard set of CRTs. Search strategies were evaluated against the gold standard set, as well as an independent set of CRTs included in previous systematic reviews. RESULTS: The existing strategy (randomized controlled trial.pt) is sensitive (93.8%) for identifying CRTs, but has relatively low precision (9%, number needed to read 11); the number needed to read can be halved to 5 (precision 18.4%) by combining with cluster design-related terms using the Boolean operator AND; combining with the Boolean operator OR maximizes sensitivity (99.4%) but would require 28.6 citations read to identify one CRT. Only about 50% of CRTs are clearly identified as cluster randomized in titles or abstracts; approximately 25% can be identified based on the reported units of randomization but are not amenable to electronic searching; the remaining 25% cannot be identified except through manual inspection of the full-text article. The proportion of trials clearly identified has increased from 28% between the years 2000-2003, to 60% between 2004-2007 (absolute increase 32%, 95% CI 17 to 47%). CONCLUSIONS: CRTs should include the phrase cluster randomized trial in titles or abstracts; this will facilitate more accurate indexing of the publication type by reviewers at the National Library of Medicine, and efficient textword retrieval of the subset employing cluster randomization

    Leadership and early strategic response to the SARS-CoV-2 pandemic at a COVID-19 designated hospital in South Africa

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    While many countries are preparing to face the COVID-19 pandemic, the reported cases in Africa remain low. With a high burden of both communicable and non-communicable disease and a resource-constrained public healthcare system, sub-Saharan Africa is preparing for the coming crisis as best it can. We describe our early response as a designated COVID-19 provincial hospital in Cape Town, South Africa (SA).While the first cases reported were related to international travel, at the time of writing there was evidence of early community spread. The SAgovernment announced a countrywide lockdown from midnight 26 March 2020 to midnight 30 April 2020 to stem the pandemic and save lives. However, many questions remain on how the COVID-19 threat will unfold in SA, given the significant informal sector overcrowding and poverty in our communities. There is no doubt that leadership and teamwork at all levels is critical in influencing outcomes

    Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR

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    New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100x larger than during its dormant state. The X-ray flux one month after reactivation was at least 800x larger than during quiescence, and has been decaying exponentially on a 111+/-19 day timescale. This high-flux state, together with a radio-derived rotational ephemeris, enabled for the first time the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV pulsed fraction is comparable to the smallest observed for magnetars. The overall pulsar geometry inferred from polarized radio emission appears to be broadly consistent with that determined 6-8 years earlier. However, rotating vector model fits suggest that we are now seeing radio emission from a different location in the magnetosphere than previously. This indicates a novel way in which radio emission from magnetars can differ from that of ordinary pulsars. The torque on the neutron star is varying rapidly and unsteadily, as is common for magnetars following outburst, having changed by a factor of 7 within six months of reactivation.Comment: Published in ApJ (2018 April 5); 13 pages, 4 figure

    A multidisciplinary study of a small, temporarily open/closed South African estuary, with particular emphasis on the influence of mouth state on the ecology of the system

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    In 2005/2006 a multidisciplinary research programme that included studies on the hydrodynamics, sediment dynamics, macronutrients, microalgae, macrophytes, zoobenthos, hyperbenthos, zooplankton, ichthyoplankton, fish and birds of the temporarily open/closed East Kleinemonde Estuary was conducted. Particular attention was given to the responses of the different ecosystem components to the opening and closing of the estuary mouth and how this is driven by both riverine and marine events. Using a complementary dataset of daily estuary mouth conditions spanning a 14-year period, five distinct phases of the estuary were identified, including closed (average = 90% of the days), outflow (<1%), tidal (9%) and semi-closed (<1%). The open-mouth phase is critical for the movements of a number of estuary-associated fish (e.g. Rhabdosargus holubi) and invertebrates (e.g. Scylla serrata) between the estuary and sea. The timing of this open phase has a direct influence on the ability of certain estuaryassociated fish (e.g. Lithognathus lithognathus) and invertebrates (e.g. Palaemon peringueyi) to successfully recruit into the system, with a spring opening (October/November) being regarded as optimal for most species. The type of mouth-breaching event and outflow phase is also important in terms of the subsequent salinity regime once the berm barrier forms. A deep mouth breaching following a large river flood tends to result in major tidal inputs of marine water prior to mouth closure and therefore higher salinities (15–25). Conversely, a shallow mouth breaching with reduced tidal exchange during the open phase often leads to a much lower salinity regime at the time of mouth closure (5–15). The biota, especially the submerged macrophytes, respond very differently to the above two scenarios, with Ruppia cirrhosa benefiting from the former and Potamogeton pectinatus from the latter. River flooding and the associated outflow of large volumes of water through the estuary can result in major declines in zooplankton, zoobenthos, hyperbenthos and fish populations during this phase. However, this resetting of the estuary is necessary because certain marine invertebrate and fish species are dependent on the opening of the estuary mouth in order to facilitate recruitment of larvae and post-larvae into the system from the sea. Slight increases in the numbers of certain piscivorous and resident wading bird species were recorded when the estuary mouth opened, possibly linked to increased feeding opportunities during that phase

    When is a randomised controlled trial health equity relevant? Development and validation of a conceptual framework

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    Background Randomised controlled trials can provide evidence relevant to assessing the equity impact of an intervention, but such information is often poorly reported. We describe a conceptual framework to identify health equity-relevant randomised trials with the aim of improving the design and reporting of such trials.Methods An interdisciplinary and international research team engaged in an iterative consensus building process to develop and refine the conceptual framework via face-to-face meetings, teleconferences and email correspondence, including findings from a validation exercise whereby two independent reviewers used the emerging framework to classify a sample of randomised trials.Results A randomised trial can usefully be classified as 'health equity relevant' if it assesses the effects of an intervention on the health or its determinants of either individuals or a population who experience ill health due to disadvantage defined across one or more social determinants of health. Health equity-relevant randomised trials can either exclusively focus on a single population or collect data potentially useful for assessing differential effects of the intervention across multiple populations experiencing different levels or types of social disadvantage. Trials that are not classified as 'health equity relevant' may nevertheless provide information that is indirectly relevant to assessing equity impact, including information about individual level variation unrelated to social disadvantage and potentially useful in secondary modelling studies.Conclusion The conceptual framework may be used to design and report randomised trials. The framework could also be used for other study designs to contribute to the evidence base for improved health equity

    Acceptability of Male Circumcision for the Prevention of HIV/AIDS in the Dominican Republic

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    Male circumcision (MC) is an effective strategy to prevent HIV infection in heterosexual men. To our knowledge, there are no studies of the acceptability of this procedure in the Dominican Republic (DR). The main objective of this study was to assess the acceptability of MC to prevent HIV transmission among men ages 18 to 50 years in the Altagracia Province in the Dominican Republic. Because differences in culture and beliefs between Haitians and Dominicans could potentially influence their acceptability of MC, we conducted a comparative analysis based on national origin.A survey was administered to a convenience sample of 368 men. The questionnaire was divided in 3 sections: 1) Background demographics (including national origin), 2) Male circumcision and 3) Sexual health. Stratified and logistic multivariate regression analyses were performed to identify factors associated with the acceptability of MC.The sample consisted of 238 (65%) Dominicans and 130 (35%) Haitian immigrants. Almost all participants were uncircumcised (95%) and about half (52%) were single. The overall acceptability of MC was 29%. The number of men willing to be circumcised increased to 67% after an information session explaining the benefits of the procedure. 74% of men reported that they would be willing to circumcise their sons after hearing that information. In multivariate analysis, Haitian nationality (OR=1.86, 95% CI 1.01-3.41), knowing that circumcision improves hygiene (OR=2.78, 95% CI 1.29-6.0) and not believing that circumcision decreases sexual pleasure (OR=2.18, 95% CI 1.20-3.94) were associated with a higher acceptability of the procedure. Although age was not significantly associated with the willingness to be circumcised in the multivariate analysis, stratified analysis based on national origin suggested that younger Dominicans (<30 years of age) are more likely to accept the procedure when compared to their older counterparts (OR=2.17, 95% CI 1.14-4.12).An important number of sexually active men in the DR may be willing to be circumcised if educational resources detailing the benefits of the procedure are made available. These educational activities would constitute a great opportunity to teach about sexual health and reinforce safe sex practices
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