What are diagnostic test accuracy reviews?
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?
Cochrane Early Career Professionals Network - Upcoming activities
The Early Career Professionals Network aims to provide its members with opportunities to enhance their knowledge, skills, and expertise by providing a platform for international networking with early career professionals or other members in the Cochrane community.
Though there is no one single definition of an ‘Early Career Professional/Researcher,’ bodies such as the European Research Commission, Economic and Social Research Council, and De Montfort University generally agree that an ECP is someone who is roughly within the first five years of their research activity. Informally, we also define an ECP as PhD students and post-docs.
This group has four main objectives, including international networking, representing trainees, active patient involvement, and knowledge translation.Upcoming Events:
Cochrane US mentoring program: past experiences and future possibilities / challenges
Date: 30 August 2022
Time: 16:00 BST (view in your time zone)
Register: Register for free!
Join Cochrane Early Career Professionals Network (ECP) as they host Cochrane US Mentoring Program founder, Tiffany Duque and former & current program participants. Hear Maria and Paola’s accounts of participating in and now working with the mentoring program - what they learned, how it has helped their careers, and what is next for them in Cochrane. Also, Year 2 mentee applicants are invited to attend to hear the final Y2 participants announced. Tiffany will talk about what is new for Year 2, and how you can get involved. Hosted by Ana Beatriz Pizarro, Year 1 program coordinator and Year 2 mentor. Come to listen and stay to ask questions! A great opportunity to learn and network! Everyone is welcome!
Ana Beatriz Pizarro, RN
Co-lead, Cochrane ECP & ExME
Member, Cochrane Editorial Board
Year 1 program coordinator
Tiffany Duque, MPH, RDN
Senior Officer, Cochrane Geographic Groups, Networks & Fields
Founder, Cochrane US Mentoring Program
Paola Andrenacci, RDN
Clinical Nutritionist - Argentina
Coordinator – Cochrane Mentoring Program
Year 1 mentee; Year 2 mentor
Maria Alejandra Barrios, MD
Professor of EBM & Director, EBM Research Center - Colombia
Year 1 mentee; Year 2 mentor
- Visit the Early Career Professionals Cochrane Network page on Cochrane Community
- View videos of past events
- Follow ECP on Twitter or check out the #CochraneEarlyCareer hashtag
Subscribe to the ECO Newsletter for a ‘one-stop-shop’ of resources, training, events, opportunities, features, blogs relevant to Early Career Researchers. Register for a Cochrane Account > My account > Communications tab > Sign up for all of the newsletters you’re interested in, including the Early Career Professionals Network newsletter.
The Cochrane-Wikipedia Partnership in 2023
Cochrane has a commitment to producing and sharing high quality health evidence to as broad an audience as possible. Cochrane partnered in 2014 with Wikipedia, with the joint goal of improving the quality and reliability of human health-related articles that people are accessing online.
Jennifer Dawson, PhD, is a Wikipedia Consultant for Cochrane. Her role includes maintaining and building further relations with Wikipedia, connecting new editors to the Wikipedia community, and supporting requests for engagement in Wikipedia work from the Cochrane community. We interviewed Jennifer to learn more about the Cochrane-Wikipedia partnership:
Why should we care about Wikipedia?
Millions of people around the world access health-related information on Wikipedia each day. Medical-related articles are available in over 286 languages on Wikipedia and often come up early on an internet search. The readership base varies broadly and includes members of the public, medical students, medical professionals, journalists, and policy makers (More info here). Given that so many people are consulting Wikipedia on a daily basis, we feel that Cochrane’s commitment to producing and sharing high quality health evidence includes sharing that evidence where people are accessing it.
What's Cochrane's Community contribution to Wikipedia?
As of 2023, 3400 Cochrane Systematic Reviews published in the past 10 years help inform evidence in medical articles shared on English Wikipedia. There are additional ongoing initiatives in other languages including Spanish, Dutch, and Farsi Wikipedias. Many Cochrane community members and volunteers participate in this initiative, collaborating with the Wikipedia editing community and using high-quality and trusted evidence to correct errors of omission, expand medical articles, and remove unreliable or outdated content shared on Wikipedia.
How can I get involved?
Nearly half of all Cochrane Reviews are already shared on Wikipedia! Cochrane is presently the most frequently cited peer-reviewed medical journal on Wikipedia (More info here). But English Wikipedia includes over 36,000 health-related articles, so there are more Cochrane reviews that still can be shared on Wikipedia. There are two main ways you can get involved:
1. Add new Cochrane Evidence to Wikipedia - Every three months, a new list of Cochrane Reviews to consider for Wikipedia is generated. Reviews to consider for Wikipedia are organized by Cochrane Review Group and can be access here: Cochrane Review List (English).
2. Ensure that the evidence already shared on Wikipedia is accurate, unbiased, and up to date. - Volunteers are needed to review what is presently shared in Wikipedia. Wikipedia articles that include out dated versions of Cochrane Reviews need to be updated. Cochrane maintains a list of Reviews that need updating. This list is refreshed monthly to include recently updated Cochrane Reviews: Cochrane-Wikipedia Update Project.
How can I edit Wikipedia in languages other than English?
Cochrane has active projects in many different languages including Spanish, French, and Dutch. Please visit the “Projects” tab project page to learn more about specific projects: Cochrane-Wikipedia Projects.
How can I learn how to edit Wikipedia?
Cochrane has developed and collated numerous training resources. Our newest resource, the Wikipedian in Training Resource, is the best place to begin. This resource shares suggested first steps, ideas for how to practice editing, and an example of the general workflow of editing Wikipedia and sharing Cochrane evidence.
Jennifer can be found on Wikipedia at: JenOttawa and by email at email@example.com. Please visit the Cochrane-Wikipedia Project Page for more information.Friday, March 24, 2023 Category: The difference we make
Evidence Synthesis - What is it and why do we need it?
We come across 'evidence syntheses' on an almost day-to-day basis, but do we know what it is and why it's so imporant?
Cochrane Ireland and Evidence Synthesis Ireland are working together to create awareness and increase knowledge and capacity in evidence synthesis methods.
Evidence synthesis, sometimes called “systematic reviews”, involves combining information from multiple studies investigating the same topic to comprehensively understand their findings. This helps determine how effective a particular treatment or drug is, or how people have experienced a particular health condition or treatment. By using evidence synthesis effectively, policymakers, healthcare institutions, clinicians, researchers, and the public can make more informed decisions about health and healthcare.
Watch this short video to learn more about evidence synthesis and why we need it:
This video was created using a user-centred design approach, using members of the public at multiple stages. You can read more about its development in this paper: Development of a video-based evidence synthesis knowledge translation resource: Drawing on a user-centred design approach.
Polycystic Ovary Syndrome Awareness Month
September is Polycystic Ovary Syndrome Awareness Month and is an excellent time to focus on the latest Cochrane evidence.
Polycystic ovary syndrome (PCOS) is a common condition with three main features:
- menstrual cycle problems, such as irregular periods or having no periods (meaning the ovaries do not release eggs)
- high levels of "male" hormones – hirsutism (excessive hair growth) or elevated testosterone
- polycystic ovaries – the ovaries contain many fluid-filled sacs (follicles) that surround the eggs.
Being overweight worsens the clinical features of PCOS. These clinical features include reproductive issues such as irregular menstrual cycles reduced frequency of ovulation, reduced fertility, polycystic ovaries on ultrasound and high levels of male hormones such as testosterone. The elevated hormone levels can cause unwanted facial or body hair growth and acne. PCOS is also associated with metabolic features, with risk factors for diabetes and cardiovascular disease including high levels of insulin or insulin resistance and abnormal cholesterol levels. PCOS affects quality of life and can worsen anxiety and depression either due to its symptoms or due to the diagnosis of a chronic disease. There is no cure for PCOS, but symptoms can be treated.
Cochrane Gynaecology and Fertility (CGF) Group is concerned with the systematic evaluation of the management and treatment of menstrual disorders and subfertility. CGF carries out extensive searches for all relevant randomised controlled trials both published and unpublished; scrutinises each trial for its relevance and quality; critically appraises trials; draws conclusions based on pooling data about how their net result should be applied in healthcare; and produces structured reports (systematic reviews) for widespread dissemination to health care providers and planners, and to consumers.
CGF has published 19 systematic reviews on the effectiveness and safety of various interventions for the treatment and management of PCOS.
Here is the curated list of our Cochrane systematic reviews on PCOS:
- Metformin treatment before and during IVF or ICSI in women with polycystic ovary syndrome
- Metformin versus the combined oral contraceptive pill for hirsutism, acne, and menstrual pattern in polycystic ovary syndrome – Blogshot available
- Metformin for ovulation induction (excluding gonadotrophins) in women with polycystic ovary syndrome - Blogshot available
- Metformin during ovulation induction with gonadotrophins followed by timed intercourse or intrauterine insemination for subfertility associated with polycystic ovary syndrome
- Gonadotrophins for ovulation induction in women with polycystic ovarian syndrome - Blogshot available
- Laparoscopic ovarian drilling for ovulation induction in women with anovulatory polycystic ovary syndrome
- Lifestyle changes in women with polycystic ovary syndrome - Blogshot available
- Acupuncture for polycystic ovarian syndrome
- Inositol for subfertile women with polycystic ovary syndrome
- In vitro maturation in subfertile women with polycystic ovarian syndrome undergoing assisted reproduction
- Chinese herbal medicine for subfertile women with polycystic ovarian syndrome
- Ultrasound-guided transvaginal ovarian needle drilling for clomiphene-resistant polycystic ovarian syndrome in subfertile women
Review updates in development
- Statins for women with polycystic ovary syndrome not actively trying to conceive
- Aromatase inhibitors for subfertile women with polycystic ovary syndrome - Blogshot available
- Ovarian surgery for symptom relief in women with polycystic ovary syndrome
- Antidepressants for polycystic ovary syndrome
- Long versus short course treatment with metformin and clomiphene citrate for ovulation induction in women with PCOS
- Pulsatile gonadotrophin releasing hormone for ovulation induction in subfertility associated with polycystic ovary syndrome
- Clomiphene and other antioestrogens for ovulation induction in polycystic ovarian syndrome
Tuesday, August 30, 2022
Call for #CochraneLondon Social Media Ambassadors - Let's get social
If you are attending the Cochrane Colloquium and already share the work of Cochrane, health evidence, or evidence synthesis methodology with your social media followers, then sign up and be an official #CochraneLondon Ambassador! Report live from the Colloquium, interview speakers, share some of the insights from each day, and go behind the scenes - all while being recognized for your work!
Cochrane UK is hosting Cochrane’s Colloquium in London, UK, 4-6 September 2023. Cochrane’s Colloquium is a global health event for everyone with an interest in the use of evidence in healthcare decision making including those engaged in evidence production, co-production, dissemination, implementation and policy making, as well as those making individual healthcare decisions. Through talks, workshops, and other activities and presentations, we will be exploring this year's theme of “Forward together for trusted evidence”.
You can find Cochrane on Twitter, Facebook, YouTube, and Instagram. We want to open up the discussion and learning that will be had at our event to everyone who wants to be involved, not just attendees and not just our regular followers. By working with others on social media, we hope to explore some of the key conference themes and highlight the work of Cochrane to new audiences including patients, health practitioners, policy-makers, guideline developers, health and science journalists, and researchers.
#CochraneLondon Ambassadors would be comprised of those attending the colloquium that are very active on social media and maintain an established, public presence on either Twitter, Instagram, LinkedIn, Facebook, and/or TikTok. We are looking for a dedicated group of social media users who will actively post before and during the Colloquium using the #CochraneLondon hashtag to create and maintain the buzz around the upcoming event and during the event itself.
What we are looking for in volunteers:
- Attending the Colloquium - preference will be given to those attending the Colloquium, although we may be open to those who want to follow along on social media.
- Creators of content in any language - we are interested in working with English and non-English creators.
- Established on social media - we are looking for podcasters, bloggers, tweeters, Instagrammers, YouTubers, TikTokers...any social media platform is great! Specialize in one or have many! You are already comfortable on your chosen platform and know how to optimize it for your followers to follow along with your experiences (e.g. using video, live tweeting).
- Have an established audience interested in health or evidence-based medicine - your audience may be interested in one specific clinical area or health issue or have a more general interest.
What you'll do:
- Post in the lead-up to the Colloquium - share that you will be attending and then at the Colloquium, share the experience with your audience. We'll also invite you to share a short video of yourself or get a quote from you about why you are attending the event to be shared on our main accounts.
- Live post during the Colloquium - videos, photos, sharing quotes from sessions, live tweeting! We want to see (and share!) your experience at the Colloquium.
- Share using the official hashtag - use #CochraneLondon so that we can see your posts and help boost the signal from Cochrane's official accounts. We'd also like you to interact with others using the hashtag before, during, and after the Colloquium.
- Use your own voice and share your own opinions - we would like you to write in your style and share content that suits your audience. You are welcome to share your opinion on Cochrane or the topics being discussed but it's important that it is clear you are giving your own opinion and not 'speaking for Cochrane'. Please see our Spokesperson Policy.
- Respond to comments and encourage discussion - discussion and debate is great! We are looking for people who use live tweeting or video to encourage people to be active participants. However, we don't encourage responding to abusive comments or comments not relevant to the matter under discussion. If individuals would like to raise issues with Cochrane outside of the scope of the social media conversation or have questions that Cochrane would be better suited to answer, please direct individuals to our 'Contact Us' page.
- Have a respectful voice and be a moderator - all posts and responses should be polite and respect others' views; even if you don't agree.
- Share your final thoughts and takeaway learning - we'd love for you to reflect on the experience in a blog post write-up. If you are interested, it may be possible to have your blog posted on one of our websites.
What selected #CochraneLondon Ambassadors will receive:
- Recognition on the official #CochraneLondon website - with your social media accounts noted to get extra exposure.
- Cochrane.org feature - be featured in a news item on Cochrane.org about the chosen Ambassadors that links out to your social media accounts; great for increasing your audience but also identifying others you may wish to collaborate with.
- Ambassador badge - your Colloquium name tag will get a special badge on it to make you easily identifiable as one of our Ambassadors.
- Access to ambassador area - a special area to meet up during breaks! A space beyond the bustle of the Colloquium to work on your laptop, conduct an interview, or charge your devices.
- Networking with others doing social media - join a special networking event on the first day to kick off the Colloquium and meet future collaborators.
- Network with Cochrane staff - a chance to meet and chat with Cochrane's Communication Department who run Cochrane and Cochrane Library social media accounts - ask them questions and network!
- Exclusive graphics - access to a folder of social media graphics you may use. We will also create some personalized ones with your headshot!
- Exclusive pictures - access to a folder of the Colloquium after each day and a chance to get new headshots taken.
- Certificate of Appreciation - an official digital Cochrane Certificate of Appreciation that can be added to your social media or resume.
- Cochrane Membership - membership points will be added to give you one year of Cochrane Membership.
How to apply:
Complete and submit this short survey by July 31, 2023 telling us about yourself, your social media accounts, and why you would like to get involved. Please note that this is an unpaid, volunteer opportunity. Those applying will be reviewed by the Colloquium Communications Committee and contacted directly.
Cochrane Clinical Answers related to COVID-19
Readable, clinically-focused, actionable answers to inform point-of-care decision-making for health professionals.
Cochrane Clinical Answers (CCAs) provide a readable, digestible, clinically-focused entry point to rigorous research from Cochrane Reviews. They are designed to be actionable and to inform point-of-care decision-making. Each CCA contains a clinical question, a short answer, and data for the outcomes from the Cochrane Review deemed most relevant to practicing healthcare professionals. The evidence is displayed in a user-friendly tabulated format that includes narratives, data, and links to graphics.
COVID-19 CCAs are available for free. Latest COVID CCAs:
- What are the benefits and risks of RNA‐based vaccines for preventing COVID‐19?
- What are the benefits and risks of inactivated virus vaccines for preventing COVID‐19?
- What are the benefits and risks of non‐replicant viral vector vaccines for preventing COVID‐19?
- What are the benefits and risks of protein subunit vaccines for preventing COVID‐19?
Get involved: The clinical answer is written either by a practicing clinician or by a CCA Editor, with the answer being peer-reviewed by a practicing clinician. If you would like to join the Clinical Answers authoring team, please contact the team at firstname.lastname@example.org. We are specifically looking for clinicians in the following areas: respiratory medicine; care of the elderly; cardiovascular medicine; pregnancy and childbirth; neurology - especially epilepsy; infectious disease; paediatrics; rheumatology; ENT; and urology.
Endometriosis Awareness Month 2022
March is Endometriosis Awareness Month. Endometriosis is an inflammatory condition where endometrial tissue (tissue similar to the lining of the uterus) grows outside of the uterus. It is estimated that 1 in 10 women have endometriosis (Zondervan 2020). Endometriosis frequently presents with the symptom of pain including dysmenorrhoea (painful periods), dyspareunia (pain during sexual intercourse), and chronic pelvic or abdominal pain. Endometriosis can cause infertility and for women with subfertility the prevalence rate ranges from 25% to 40% (Ozkan 2008).
Cochrane Gynaecology and Fertility group has published over 20 intervention reviews and protocols investigating the effectiveness and safety of treatments for the management of endometriosis. In addition, they have published five diagnostic test accuracy reviews assessing the effectiveness of various tests in the diagnosis of endometriosis. They are joining #EndometriosisAwarenessMonth by sharing an updated collection of their reviews on endometriosis that focus on pain-related outcomes and fertility outcomes. The treatments include pharmacological interventions (hormonal therapy, immune-modulators, anti‐inflammatory drugs), surgery, and alternative medicine. Throughout Endometriosis Awareness Month, they will be also sharing blogs that include relevant Cochrane evidence and other information to help inform women’s decisions about endometriosis diagnosis and treatment.
Get Social with Cochrane!
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:
- Twitter - @CochraneCollab @CochraneLibrary @CochraneConsumr @Cochrane_Crowd
- Facebook - Cochrane, Cochrane Library and Cochrane Consumer Network
- Instagram - @Cochraneorg
We love to engage with our Community and retweet or share to Instagram stories! 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:
Collection of Cochrane evidence on diagnosing tuberculosis
The Union Conference, a world conference on lung health, is taking place 8-11 November 2022. To mark this, Cochrane Infectious Diseases have released an updated collection on diagnosing tuberculosis, which highlights Cochrane Reviews relevant to this topic.
Tuberculosis continues to cause great suffering worldwide. According to the World Health Organization (WHO), in 2021 an estimated 10.6 million people developed tuberculosis, an increase of 4.5% from 2020.
This collection includes selected systematic reviews from Cochrane Infectious Diseases and other international teams that underpin three WHO consolidated guidelines on systematic screening for tuberculosis disease and on rapid diagnostics for detection of tuberculosis and tuberculosis drug resistance. The collection highlights how Cochrane evidence contributes within a wider landscape of tuberculosis evidence and guidelines.
Lead image credit: The Global Fund/Jonas GratzerMonday, November 7, 2022
VIDEO: What are systematic reviews?
A systematic review attempts to identify, appraise and synthesize all the empirical evidence that meets pre-specified eligibility criteria to answer a specific research question. Researchers conducting systematic reviews use explicit, systematic methods that are selected with a view aimed at minimizing bias, to produce more reliable findings to inform decision making.
Here is a video from Cochrane Consumers and Communication that explains what a systematic review is clearly and simply for people who may not be familiar with the concepts and terminology of systematic reviews: what they are, how researchers prepare them, and why they’re an important part of making informed decisions about health - for everyone.
Cochrane evidence provides a powerful tool to enhance your healthcare knowledge and decision making. This video from Cochrane Sweden explains a bit about how we create health evidence, including systematic reviews, and other activities of Cochrane.
Cochrane evidence in different languages
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 44,000 translations of Cochrane health evidence summaries across 15 languages as of January 2023.
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
Most translated Cochrane Reviews:
- Acupuncture and related interventions for smoking cessation (15 languages)
- Vitamin C for preventing and treating the common cold (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.
What is Cochrane?
Cochrane exists so that healthcare decisions get better.
Cochrane is a global independent network of researchers, professionals, patients, carers, and people interested in health. Many of our contributors are world leaders in their fields - medicine, health policy, research methodology, or consumer advocacy - and our groups are situated in some of the world's most respected academic and medical institutions.
Cochrane contributors work together to produce credible, accessible health information that is free from commercial sponsorship and other conflicts of interest. This is vital for us to generate authoritative and reliable information, working freely, unconstrained by commercial and financial interests. We gather and analyze the best available evidence to help people make informed decisions about health and health care. These are called systematic reviews. Our work is recognized as representing an international gold standard for high quality, trusted information.
The need for Cochrane's work is even greater than it was when we started in 1993. As access to health evidence increases, so do the risks of misinterpreting complex content; meanwhile the likelihood of any one person getting a complete and balanced picture decreases. Our mission to provide accessible, credible information to support informed decision-making has never been more important or useful for improving global health.
It’s hard to stay up-to-date with the latest health evidence. Listen to leading experts and Cochrane review authors explain in plain language the evidence and findings of their high-impact reviews. In 5 minutes or less, healthcare professionals to patients and families can understand the latest trusted evidence to help make better informed decisions.
For 20 years, Cochrane has produced systematic reviews which are internationally recognized as the highest standard in evidence-based health care resources. Cochrane works collaboratively with contributors around the world to produce authoritative, relevant, and reliable evidence.
You can view and search our entire catalogue of hundreds of podcasts or subscribe via Apple Podcast, Google Podcasts, or Spotify for the latest updates.Monday, March 7, 2022
Clinical Trials Day 2023
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:
Advocacy on 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. Cochrane’s community is active in campaigning for improved clinical trial transparency.
During the last 12 months, there have been major milestones in this area. At last year’s World Health Assembly, WHO Member States adopted a resolution on clinical trials which references transparency obligations. As well as demonstrating high-level political support for the importance of robust, transparent clinical trial practices, the resolution has spearheaded a number of activities as part of its implementation.
In addition, the UK Government recently announced new stricter legislation formalising the requirements to register and report on clinical trials in a timely manner. This is in line with our long-term advocacy recommendations.
However, there is still much more to be done in this area.
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.
"While it is heartening to have seen some significant improvements in clinical trial transparency in recent years, there is still much more to be done worldwide," says Emma Thompson, Cochrane Advocacy and Partnership Lead."Cochrane will continue to push for the fulfilment of this key ethical, and often legal, responsibility."Cochrane's clinical trial transparency advocacy:
- Cochrane and Cochrane Germany participate in live session on driving clinical trial reporting
- 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
- Read the Evidently Cochrane blog post 'Retention to clinical trials: how can we keep participants involved?'
- Read the Cochrane Review 'Strategies to improve retention in randomised trials'
- Clinical Trial Transparency: A guide for policymakers - English, German, Italian
- Strategies to improve retention in randomised trials
- Factors that impact on recruitment to randomised trials in health care: a qualitative evidence synthesis
Friday, May 19, 2023
Updated review: Insufficient evidence for use of Omega-3 supplements in treating depression
Updated Cochrane research concludes that there is insufficient evidence for the use of Omega-3 fatty acid supplements in treating major depressive disorder.
Omega-3 fatty acids are widely thought to be essential for good health and are naturally found in fatty fish such as mackerel; other seafood; and some nuts and seeds.
Omega-3 fatty acids have been widely promoted globally for a variety of health concerns, and are readily available as an over-the-counter supplement. These supplements have hugely increased in popularity over the last decade, together with a range of other supplements including ginseng, garlic, green tea, vitamins, minerals, and herbal products.
There have been various studies that have suggested a role for Omega-3 fatty acid supplementation in treating major depressive disorder. Adults with major depressive disorders are characterized by depressed mood or a lack of pleasure in previously enjoyed activities for at least two weeks, in the absence of any physical cause, that impact on everyday life.
Figures published in 2018 estimated prevalence rates for major depressive disorders of 163 million cases in 2017, and global incidence rates of 242 million cases, resulting in 33 million years lived with disability globally, an increase of 12.6% since 2007.
This updated Cochrane Review, published recently in the Cochrane Library, gathered together data from 28 randomized trials involving a total of 1944 participants. The trials investigated the impact of giving an Omega-3 fatty acid supplement in a capsule form and compared it to a dummy pill. In one study, involving 40 participants, researchers also investigated the impact of the same supplementation compared to an anti-depressant treatment.
The Cochrane authors found that, whilst people who were given Omega-3 fatty acids reported lower symptom scores than people with the dummy pill, the effect was small and there were important limitations that undermined their confidence in the results. Their analyses showed that although similar numbers of people experienced side effects, more data would be required to understand the risks of taking Omega-3 fatty acids.
Lead author Katherine Appleton from Bournemouth University said, “This is an update of an existing Cochrane Review, using the same methods as we previously used, with some refinements. The update includes 8 randomised controlled trials published since 2015, in addition to the 20 trials included in the previous review.
Our conclusions however remain unchanged. We found a small-to-modest positive effect of Omega-3 fatty acids compared to placebo for depressive symptomology, but the size of this effect is unlikely to be meaningful to people with depression, and we considered the evidence on which this conclusion was based to be of low or very low quality. All studies contributing to our analyses were of direct relevance to our research question, but most of these studies are small and of low quality. We also found insufficient evidence to clearly determine the effects of omega-3 oils on negative side effects or when compared with anti-depressants.”
She added, “At present, we just don’t have enough high-quality evidence to determine the effects of Omega-3 fatty acids as a treatment for major depressive disorder. It’s important that people who suffer from depression are aware of this, so that they can make more informed choices about treatment.”
- View the full update review
- View the Cochrane Common Mental Disorders Group page
- Read the press release for previous version in Spanish and Russian
Tuesday, December 7, 2021