Cochrane systematic reviews can help us to make healthcare decisions based on up-to-date research evidence. They are systematic because they search for and analyse evidence in a systematic way, according to predetermined and published methods. Each systematic review answers a specific healthcare question by gathering all the relevant studies, assessing the reliability of these studies, then summarising their results to produce a summary of all of the available evidence.

One type of systematic review is a diagnostic test accuracy (DTA) review. In addition to investigating test accuracy, they ideally also investigate why the results may vary among studies, compare the performance of alternative tests, and help the reader to put the evidence in a clinical context. Watch the video below and read on to learn more about DTA reviews.

Cochrane DTA reviews are a type of systematic review that aim to evaluate the accuracy of diagnostic tests. They want to find out whether a new test is more accurate than an existing test, or whether it is quicker, cheaper or easier to perform. Answers to these questions help patients and healthcare workers make informed decisions about which test to use, based on up-to-date evidence. 

DTA reviews evaluate how well diagnostic tests (index tests) identify or exclude a particular disease or condition (the target condition). We know that diagnostic tests make errors, even when they are correctly performed. There are two types of test errors: false positive test errors (the index test suggests the target condition is present when it is not) and false negative test errors (the test suggests the target condition is absent when it is not). Cochrane DTA reviews can cover all types of diagnostic tests, from antibody tests to X-rays, for any disease or condition. It is really important that diagnostic tests provide accurate results so that people can receive prompt treatment or take preventive measures if necessary, and to avoid unnecessary testing, treatment and anxiety. 

DTA reviews search for all relevant test accuracy studies, appraise the studies for reliability, and combine their results. This gives the best possible estimate of the accuracy of an index test based on all the available evidence. DTA reviews are systematic because they search for and analyze evidence in a systematic way, according to predetermined and published methods.

Test accuracy studies most often report accuracy using sensitivity and specificity. 

• Sensitivity means the proportion of people with the target condition who are correctly detected by the index test. 
• Specificity means the proportion of people without the target condition who are correctly identified by the index test. 

Therefore, the nearer the sensitivity and specificity are to 100%, the better the test.

An alternative way to report test accuracy is using positive and negative predictive values, which tell us about the usefulness of a positive index test result and a negative index test respectively – this helps patients understand how reliable their test results are. Predictive values measure the number of positive index test results that will be true positives and the number of negative index test results that will be true negatives. The nearer the positive and negative predictive values are to 100%, the better the test. 

• View Cochrane DTA training for authors
• Visit the Cochrane Screening and Diagnostic Test Methods group website
• Read the Students 4 Best Evidence blog post 'Diagnostics Studies: how to get started with appraising the evidence'
• Learn more: What is the difference between a Cochrane systematic review of interventions and a Cochrane diagnostic test accuracy review?

Friday, March 22, 2024

We aim to put Cochrane evidence at the heart of health decision-making all over the world. This not only means producing high-quality and relevant systematic reviews but making sure that our evidence is accessible and advocating for evidence. Join us on social media to learn more about the work we do, our community, and the health evidence we produce.

You can access Cochrane evidence and news on your favourite social media platform! Follow us on:

• X - @CochraneCollab @CochraneLibrary @CochraneConsumr 
• Facebook - Cochrane,  Cochrane Library and Cochrane Consumer Network
• YouTube
• Instagram - @Cochraneorg
• LinkedIn

We love to engage with our Community   Be sure to tag a Cochrane social media account  so that we see the post. 

Share a picture of you enjoying Cochrane training, using the Cochrane Handbook, or share the latest Cochrane evidence. Your social media posts can earn you contribution points to work towards gaining full Cochrane Membership! Share, tag us, and add  your contribution to your free account. 

If you're interested in learning more about sharing on social media, check out these resources:

• Cochrane social media tips
• Checklist for disseminating health evidence
• Guide to choosing images when sharing health evidence

Wednesday, August 14, 2024

Only about 6% of the world’s population are native English speakers, and 75% of people don’t speak English at all.

Many people do not have access to high-quality health information, because it is not available in a language that they understand. We translate Cochrane evidence to make it more accessible, and to reduce the linguistic barrier to global evidence-informed health decisions.

Cochrane groups in different parts of the world lead our knowledge translation activities in different languages. They translate Cochrane Reviews and related content, such as podcasts or blogshots. They also produce and share information in their language, do social media, work with professional societies, policy makers, patient groups or the media in their country, and offer training.

We have published more than 49,000 translations of Cochrane health evidence summaries across 20 languages as of January 2024.

Read Cochrane evidence on cochrane.org in different languages. You can see all available languages on the top of each page on cochrane.org, and click on it to switch the language. Or click here:

• Simplified Chinese
• Traditional Chinese
• Croatian
• Dutch
• French
• German
• Hindi
• Hungarian
• Indonesian
• Japanese
• Korean
• Malay
• Persian
• Polish
• Portuguese
• Romanian
• Russian
• Spanish
• Tamil
• Thai

Most translated Cochrane Reviews:

• Vitamin C for preventing and treating the common cold (16 languages)
• Acupuncture and related interventions for smoking cessation (15 languages)
• Smoking reduction interventions for smoking cessation (15 languages)
• Pilates for low back pain (15 languages)

Cochrane podcasts in different languages: Cochrane podcasts are a short audio summary of a Cochrane review and have been recorded in 40+ languages.

• Learn more about Cochrane's multi-language projects
• Learn how you can get involved in translation at Cochrane

Monday, February 12, 2024

Clinical Trials Day is celebrated on 20 May marking the day in 1747 on which James Lind is believed to have begun the first known controlled trial, comparing different treatments for scurvy which was common among sailors in the British Royal Navy. Watch a video explaining the trial to see history in the making.

Learn about Cochrane systematic reviews and how clinical trials are used:

Continuing to fight for greater clinical trial transparency 

Registering and reporting the results of clinical trials is an ethical, and often legal, responsibility. However, it is well documented that the results of many studies are never published. This contributes to research waste and can even lead to people being harmed.   

Continuing with Cochrane’s long-term advocacy and campaigning around improved clinical trial transparency, we have been involved in major milestones in this area. Here are some of the highlights from the past 12 months: 

Supporting global policy 
Cochrane has continued to support WHO with the implementation of resolution WHA75.8 on strengthening clinical trials globally. This includes through responding to and disseminating a public consultation on clinical trials best practice and inviting WHO colleagues to present about the resolution in a session at the Cochrane Colloquium in London. Cochrane’s Editor in Chief, Dr Karla Soares-Weiser, is also contributing to the technical advisory group established to support the resolution in a personal capacity. 

Cochrane Denmark, Norway and Sweden advocating to end research waste in Nordic countries
Cochrane Denmark, Cochrane Norway, and Cochrane Sweden, along with AllTrials campaign, the Dam Foundation, Melanomföreningen, and TranspariMED, jointly published a report that found that 475 academically led clinical trials involving 83,903 patients completed during 2016-19 in Denmark, Iceland, Finland, Norway and Sweden have never made their results public in any form. This gained widespread media coverage, including calls from the Norwegian State Secretary for the Ministry of Health to action the findings from the report.  

Following the publication of the report, Cochrane groups in Nordic countries have continued to keep attention on the topic by engaging with universities and sending questionnaires to researchers connected to the reported missing trials to investigate why clinical trial data hasn’t been published. To support institutions in reporting in clinical trials, Cochrane Norway and the Dam Foundation also held a webinar aimed at addressing some of the challenged and issues around clinical trial reporting.  

Supporting clinical trial transparency in the EU 
Representatives of Cochrane, Cochrane France and Cochrane Germany met with the European Medicines Agency (EMA) to discuss how to support the EMA’s Clinical Trials Information System (CTIS) in its transparency objectives in order to benefit health research. The CTIS contains details on clinical trials currently underway and results summaries for completed trials. This is a valuable resource for researchers to identify studies which might not otherwise be accessible for evidence synthesis.  

Cochrane Germany push for German university hospitals to publish all clinical trial data
Most recently, Cochrane Germany, alongside the German Network for Evidence-Based Medicine, HTA.de and the BIH Quest Center, published a policy position paper that highlighted that one third of all clinical trials led by German university hospitals between 2014-2017 remained unpublished for five years after completion. They called on the Federal Ministry of Health and the Federal Ministry of Education and Research to create appropriate framework conditions for complete study registration and timely publication of results in Germany and to propose a regulation. 

Cochrane’s systematic reviews rely upon the results of clinical trials. To assess the effectiveness and safety of healthcare interventions, we need to know what trials were done, how they were conducted and what their findings were. Without access to detailed information from all clinical trials, we cannot have a full picture of the evidence. 

 

“Cochrane is pleased to be at the forefront of some significant improvements in clinical trial transparency. However, we must ensure that this momentum continues as there is much more to be done globally. We will continue advocating for clinical trial transparency and will fight for this key ethical and legal responsibility to be met.” says Catherine Spencer, Cochrane Chief Executive Officer. Cochrane's clinical trial transparency advocacy: 

• Cochrane Germany reports that one third of all German university clinical trials remain unpublished
• Cochrane Denmark, Sweden, and Norway find that hundred of Nordic Trials remain unpublished 
• Cochrane encourages participation in WHO consultations following resolution
• Article by Cochrane France on clinical trial transparency and COVID-19 trials 
• Cochrane Convenes report, which covers key issues around clinical trials in emergency conditions 
• Cochrane participates in a session on Clinical Trials and COVID-19
• Cochrane Sweden host webinar on clinical trial transparency
• Cochrane Germany article on clinical trial transparency in the EU and advocacy activities in Germany 
• Cochrane's statement to the 74th World Health Assembly 
• Cochrane shows support for WHO-ICMRA statement on transparency and data integrity
• Cochrane signs letter asking medicines regulators in Europe to address unpublished clinical trials
• US FDA begins enforcement of clinical trial transparency regulation
• Cochrane Belgium partners on clinical trial transparency report
• Cochrane Austria launches joint trial transparency report
• Cochrane Sweden highlights under-reporting of Swedish clinical trials

Cochrane Library systematic reviews of interest: 

• Strategies to improve retention in randomised trials
• Factors that impact on recruitment to randomised trials in health care: a qualitative evidence synthesis

Cochrane training resources of interest: 

• Cochrane Evidence Essentials - Module 2: Randomized controlled trials
• Testing Treatments 

 

Friday, May 17, 2024