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Cochrane Collaboration

NonprofitOxford, United Kingdom
About: Cochrane Collaboration is a nonprofit organization based out in Oxford, United Kingdom. It is known for research contribution in the topics: Systematic review & Randomized controlled trial. The organization has 1995 authors who have published 3928 publications receiving 382695 citations.


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Journal ArticleDOI
TL;DR: A freely available web-based “point and click” interactive tool which allows users to input their DTA study data and conduct meta-analyses for DTA reviews, including sensitivity analyses, and allows for sensitivity analyses to be conducted in a timely manner.
Abstract: Recommended statistical methods for meta-analysis of diagnostic test accuracy studies require relatively complex bivariate statistical models which can be a barrier for non-statisticians. A further barrier exists in the software options available for fitting such models. Software accessible to non-statisticians, such as RevMan, does not support the fitting of bivariate models thus users must seek statistical support to use R, Stata or SAS. Recent advances in web technologies make analysis tool creation much simpler than previously. As well as accessibility, online tools can allow tailored interactivity not found in other packages allowing multiple perspectives of data to be displayed and information to be tailored to the user’s preference from a simple interface. We set out to: (i) Develop a freely available web-based “point and click” interactive tool which allows users to input their DTA study data and conduct meta-analyses for DTA reviews, including sensitivity analyses. (ii) Illustrate the features and benefits of the interactive application using an existing DTA meta-analysis for detecting dementia. To create our online freely available interactive application we used the existing R packages lme4 and Shiny to analyse the data and create an interactive user interface respectively. MetaDTA, an interactive online application was created for conducting meta-analysis of DTA studies. The user interface was designed to be easy to navigate having different tabs for different functions. Features include the ability for users to enter their own data, customise plots, incorporate quality assessment results and quickly conduct sensitivity analyses. All plots produced can be exported as either .png or .pdf files to be included in report documents. All tables can be exported as .csv files. MetaDTA, is a freely available interactive online application which meta-analyses DTA studies, plots the summary ROC curve, incorporates quality assessment results and allows for sensitivity analyses to be conducted in a timely manner. Due to the rich feature-set and user-friendliness of the software it should appeal to a wide audience including those without specialist statistical knowledge. We encourage others to create similar applications for specialist analysis methods to encourage broader uptake which in-turn could improve research quality.

121 citations

Journal ArticleDOI
TL;DR: Evidence is provided that LT4 supplementation should be recommended to improve clinical pregnancy outcome in women with subclinical hypothyroidism and/or thyroid autoimmunity undergoing ART and in an ART setting where no data is available.
Abstract: BACKGROUND Previous meta-analyses of observational data indicate that pregnant women with subclinical hypothyroidism have an increased risk of adverse pregnancy outcome. Potential benefits of levothyroxine (LT4) supplementation remain unclear, and no systematic review or meta-analysis of trial findings is available in a setting of assisted reproduction technologies (ART). METHODS Relevant trials published until August 2012 were identified by searching MEDLINE, EMBASE, Web of Knowledge, the Cochrane Controlled Trials Register databases and bibliographies of retrieved publications without language restrictions. RESULTS From 630 articles retrieved, we included three trials with data on 220 patients. One of these three trials stated 'live delivery' as outcome. LT4 treatment resulted in a significantly higher delivery rate, with a pooled relative risk (RR) of 2.76 (95% confidence limits 1.20-6.44; P = 0.018; I(2) = 70%), a pooled absolute risk difference (ARD) of 36.3% (3.5-69.0%: P = 0.030) and a summary number needed to treat (NNT) of 3 (1-28) in favour of LT4 supplementation. LT4 treatment significantly lowered miscarriage rate with a pooled RR of 0.45 (0.24-0.82; P = 0.010; I(2) = 26%), a pooled ARD of -31.3% (-48.2 to -14.5%: P < 0.001) and a summary NNT of 3 (2-7) in favour of LT4 supplementation. LT4 treatment had no effect on clinical pregnancy (RR 1.75; 0.90-3.38; P = 0.098; I(2) = 82%). In an ART setting, no data are available on the effects of LT4 supplementation on premature delivery, arterial hypertension, placental abruption or pre-eclampsia. CONCLUSIONS Our meta-analyses provide evidence that LT4 supplementation should be recommended to improve clinical pregnancy outcome in women with subclinical hypothyroidism and/or thyroid autoimmunity undergoing ART. Further research is needed to determine pregnancy outcome after close monitoring of thyroid function to maintain thyroid-stimulating hormone and free T4 levels within the trimester-specific reference ranges for pregnancy.

121 citations

Journal ArticleDOI
15 Jan 2004-BMJ
TL;DR: Information provided by professional advocacy groups and governmental organisations is information poor and severely biased in favour of screening, and few websites live up to accepted standards for informed consent.
Abstract: Objective To investigate whether information on mammographic screening presented on websites by interest groups is balanced, is independent of source of funding, and reflects recent findings. Design Cross sectional study using a checklist with 17 information items. Setting 27 websites in Scandinavian and English speaking countries. Results The 13 sites from advocacy groups and the 11 from governmental institutions all recommended mammographic screening, whereas the three from consumer organisations questioned screening (P = 0.0007). All the advocacy groups accepted industry funding, apparently without restrictions. In contrast the three consumer organisations acknowledged the risk of bias related to industry funding, and two of them did not accept such funding at all. Advocacy groups and governmental organisations favoured information items that shed positive light on screening. The major harms of screening, overdiagnosis and overtreatment, were mentioned by only four of these groups, but by all three sites from consumer organisations (P = 0.02). In addition, the chosen information was often misleading or erroneous. The selection of information items for websites did not reflect recent findings, apart from the consumer sites, which were much more balanced and comprehensive than other sites (median of 9 information items v3 items, P = 0.03). Conclusions The information material provided by professional advocacy groups and governmental organisations is information poor and severely biased in favour of screening. Few websites live up to accepted standards for informed consent such as those stated in the General Medical Council9s guidelines.

121 citations

Journal ArticleDOI
TL;DR: Overall, there are important gaps in the availability of systematic reviews and primary studies for the all of the main categories of governance arrangements, but moderate‐ or high‐certainty evidence shows desirable effects (with no undesirable effects) for some interventions.
Abstract: Background One target of the Sustainable Development Goals is to achieve "universal health coverage, including financial risk protection, access to quality essential health-care services and access to safe, effective, quality and affordable essential medicines and vaccines for all". A fundamental concern of governments in striving for this goal is how to finance such a health system. This concern is very relevant for low-income countries. Objectives To provide an overview of the evidence from up-to-date systematic reviews about the effects of financial arrangements for health systems in low-income countries. Secondary objectives include identifying needs and priorities for future evaluations and systematic reviews on financial arrangements, and informing refinements in the framework for financial arrangements presented in the overview. Methods We searched Health Systems Evidence in November 2010 and PDQ-Evidence up to 17 December 2016 for systematic reviews. We did not apply any date, language, or publication status limitations in the searches. We included well-conducted systematic reviews of studies that assessed the effects of financial arrangements on patient outcomes (health and health behaviours), the quality or utilisation of healthcare services, resource use, healthcare provider outcomes (such as sick leave), or social outcomes (such as poverty, employment, or financial burden of patients, e.g. out-of-pocket payment, catastrophic disease expenditure) and that were published after April 2005. We excluded reviews with limitations important enough to compromise the reliability of the findings. Two overview authors independently screened reviews, extracted data, and assessed the certainty of evidence using GRADE. We prepared SUPPORT Summaries for eligible reviews, including key messages, 'Summary of findings' tables (using GRADE to assess the certainty of the evidence), and assessments of the relevance of findings to low-income countries. Main results We identified 7272 reviews and included 15 in this overview, on: collection of funds (2 reviews), insurance schemes (1 review), purchasing of services (1 review), recipient incentives (6 reviews), and provider incentives (5 reviews). The reviews were published between 2008 and 2015; focused on 13 subcategories; and reported results from 276 studies: 115 (42%) randomised trials, 11 (4%) non-randomised trials, 23 (8%) controlled before-after studies, 51 (19%) interrupted time series, 9 (3%) repeated measures, and 67 (24%) other non-randomised studies. Forty-three per cent (119/276) of the studies included in the reviews took place in low- and middle-income countries. Collection of funds: the effects of changes in user fees on utilisation and equity are uncertain (very low-certainty evidence). It is also uncertain whether aid delivered under the Paris Principles (ownership, alignment, harmonisation, managing for results, and mutual accountability) improves health outcomes compared to aid delivered without conforming to those principles (very low-certainty evidence). Insurance schemes: community-based health insurance may increase service utilisation (low-certainty evidence), but the effects on health outcomes are uncertain (very low-certainty evidence). It is uncertain whether social health insurance improves utilisation of health services or health outcomes (very low-certainty evidence). Purchasing of services: it is uncertain whether increasing salaries of public sector healthcare workers improves the quantity or quality of their work (very low-certainty evidence). Recipient incentives: recipient incentives may improve adherence to long-term treatments (low-certainty evidence), but it is uncertain whether they improve patient outcomes. One-time recipient incentives probably improve patient return for start or continuation of treatment (moderate-certainty evidence) and may improve return for tuberculosis test readings (low-certainty evidence). However, incentives may not improve completion of tuberculosis prophylaxis, and it is uncertain whether they improve completion of treatment for active tuberculosis. Conditional cash transfer programmes probably lead to an increase in service utilisation (moderate-certainty evidence), but their effects on health outcomes are uncertain. Vouchers may improve health service utilisation (low-certainty evidence), but the effects on health outcomes are uncertain (very low-certainty evidence). Introducing a restrictive cap may decrease use of medicines for symptomatic conditions and overall use of medicines, may decrease insurers' expenditures on medicines (low-certainty evidence), and has uncertain effects on emergency department use, hospitalisations, and use of outpatient care (very low-certainty evidence). Reference pricing, maximum pricing, and index pricing for drugs have mixed effects on drug expenditures by patients and insurers as well as the use of brand and generic drugs. Provider incentives: the effects of provider incentives are uncertain (very low-certainty evidence), including: the effects of provider incentives on the quality of care provided by primary care physicians or outpatient referrals from primary to secondary care, incentives for recruiting and retaining health professionals to serve in remote areas, and the effects of pay-for-performance on provider performance, the utilisation of services, patient outcomes, or resource use in low-income countries. Authors' conclusions Research based on sound systematic review methods has evaluated numerous financial arrangements relevant to low-income countries, targeting different levels of the health systems and assessing diverse outcomes. However, included reviews rarely reported social outcomes, resource use, equity impacts, or undesirable effects. We also identified gaps in primary research because of uncertainty about applicability of the evidence to low-income countries. Financial arrangements for which the effects are uncertain include external funding (aid), caps and co-payments, pay-for-performance, and provider incentives. Further studies evaluating the effects of these arrangements are needed in low-income countries. Systematic reviews should include all outcomes that are relevant to decision-makers and to people affected by changes in financial arrangements.

121 citations

Journal ArticleDOI
TL;DR: The incidence of invasive pneumococcal disease appeared consistently lower in western European countries compared with studies from the USA, and the use of studies of vaccine effectiveness based on the US population may lead to an overestimation of the benefits of its introduction in Europe.
Abstract: Summary We did a systematic search and synthesis of evidence on the incidence of invasive pneumococcal disease, symptomatic disease, and circulating Streptococcus pneumoniae serotypes in western Europe. Using data from studies published between 1992 and 2005 we calculated a weighted mean invasive pneumococcal disease and pneumococcal meningitis incidence rate per 100 000 children aged 2 years or younger within 95% confidence intervals, together with the prevalence of S pneumoniae serotypes and resistance to penicillin. Invasive pneumococcal disease incidence was 27·03 cases per 100 000 children under 2 years (95% CI 2·85–33·43). Heptavalent conjugate vaccine serotypes account for 43·18–75·32% of isolates among people aged under 18 years of age. 11% of isolates in individuals aged under 18 years were penicillin resistant. The incidence of invasive pneumococcal disease appeared consistently lower in western European countries compared with studies from the USA. Thus the use of studies of vaccine effectiveness based on the US population may lead to an overestimation of the benefits of its introduction in Europe.

121 citations


Authors

Showing all 2000 results

NameH-indexPapersCitations
Douglas G. Altman2531001680344
John P. A. Ioannidis1851311193612
Jasvinder A. Singh1762382223370
George A. Wells149941114256
Shah Ebrahim14673396807
Holger J. Schünemann141810113169
Paul G. Shekelle132601101639
Peter Tugwell129948125480
Jeremy M. Grimshaw123691115126
Peter Jüni12159399254
John J. McGrath120791124804
Arne Astrup11486668877
Mike Clarke1131037164328
Rachelle Buchbinder11261394973
Ian Roberts11271451933
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20231
202210
2021289
2020288
2019215
2018213