Trip Database Blog

Liberating the literature

Making Trip Pro available for health professionals in Africa

Ariadne Labs is a joint center for health systems innovation at Brigham and Women’s Hospital and the Harvard T.H. Chan School of Public Health. They approached Trip earlier in the year to take part in their Better Evidence initiative and this has resulted in Trip Pro being made available, for free, in 20 schools across 12 countries in Africa.

Searching for evidence to improve care during wartime

In little over 24 hours we’ve made some significant changes to the combat injuries filter. We’ve increased the yield of higher-quality articles from 2,000 to nearly 4,000. In conversation with people it’s become apparent that simply pointing to a large number of results isn’t great – as it suggests the user will have to browse the articles. In actual fact, they are more likely to have a clinical question.

So, we’re going to try to create an evidence table, pre-loaded with possible questions. As with the previous post, this table should be added to as and when people reach out. If you have suggestions, please send them to And, to be clear, we’re not experts in this domain, hence being very open to help.

TopicCombat setting (higher-quality evidence)Combat setting (all evidence)Any setting (higher-quality evidence)Any setting (all evidence)
Amputation121 results965 results1,613 results13,515 results
Antibiotics504 results4,100 results11,793 results148,176 results
Anxiety702 results2,628 results12,273 results87,007 results
Bullet wounds65 results522 results65 results522 results
Burns572 results2,719 results4,005 results28,571 results
Compartment syndrome174 results963 results947 results14,125 results
First aid93 results266 results402 results1,752 results
PTSD611 results2,979 results3,123 results17,085 results
Tranexamic acid42 results111 results696 results3,226 results
Venous thromboembolism164 results464 results3,192 results14,389 results

Thanks to Tom for highlighting refugee health. The following do not have any combat setting filter, they’re just total topic results:

TopicHigher-quality evidenceAll evidence
PTSD refugees207 results565 results
Refugee health648 results2,782 results
Refugee mental health455 results1,292 results
Unaccompanied minor refugees36 results92 results

Kate has highlighted the wonderful Evidence Aid. They have a number of pertinent evidence collections, including Health of refugees and asylum seekers.

Again, any suggestions via

Search filter for combat injuries

Earlier today I heard on the radio about two British surgeons running online training on military surgical techniques for surgeons/doctors in Ukraine. As Trip is a global repository of some of the best evidence available we thought it might be beneficial to try to bring together some of the best ‘combat’ evidence. To that end we have started work on a search filter. This is our starting list:

  • (shrapnel AND (wound OR injury))
  • military
  • soldier
  • (post-traumatic stress disorder AND (soldier or military))
  • (bomb AND injuries)
  • (bullet AND (wound OR injury))
  • (bomb AND (wound OR injury))

These translates to this search string, which is 20,000 results. If you restrict to ‘evidence based’ content (this search string) it drops to a more manageable 2,000 results. However, this is still too many so it possibly requires more filtering. For instance:

Can you help us improve our offering? I guess this comes in two parts (1) improve the filter to locate more military-related articles, and (2) suggestions for pre-formulated searches (such as the surgery or shrapnel searches above)

Any suggestions please send them to

UPDATE (15:26 on 06/03/2022)

Thanks to Becky I’ve added some additional terms:

  • “armed forces”
  • warfare
  • army
  • navy
  • airforce

This finds extra articles, unfiltered it’s now just over 28,000 results, and just over 2,600 higher quality articles.

UPDATE (11:52 on 07/03/2022)

Thanks to Lina we’ve identified a number of new terms:

  • gunshot
  • firearm
  • blast
  • explosion

This now gives just over 44,000 results, and just over 3,500 for higher-quality content.

Update (14:01 on 07/03/2022)

Thank you to Igor and Tracy we’ve identified some other useful terms:

  • shelling
  • grenade
  • “land mine”
  • landmine
  • artillery

This now gives just over 50,000 total results with nearly 4,000 higher-quality results.

Years covered by Trip

We’ve just been contacted by a doctor undertaking a systematic review and he asked, for writing up the search strategy, how far back do our records go. Unfortunately it is not possible to give a definitive answer!

In part this relates to the recent post Journal coverage in Trip where we highlight the nature of incorporating documents. We typically say that the bulk of our content is from the year 2000 onwards. However, as we grab all the RCTs and systematic reviews in PubMed, those are our earliest records. So, we’ve got some systematic reviews and and RCTs from the 1950s (although the definition of these research types may well have changed since then) and our earliest guideline appears to be from the late 1990s!.

New sources added to Trip

Trip is only as good as the content it searches, and as such, we are constantly exploring new sources of evidence to add. We are supported in this by our users who often contact us to alert us to content we don’t already include and we typically add new sources every month. This month has been particularly productive with 5 new publications. Four of these  (the Health Technology Assessments) were highlighted by a senior HTA investigator. The new sources are:

  • Adelaide Health Technology Assessment
  • AETSA HTA (Spain)
  • Government of Alberta HTA
  • Council for Choices in Health Care HTA (Finland)
  • American Diabetes Association – guidelines

If you know of a source you think would be useful for Trip and it’s users then please get in touch

An important collection of posts to help you use and understand Trip

We regularly post blog articles highlighting a particular aspect of Trip. As these grow, having them in one place makes sense, so here we go!

Obtaining an overview of Trip

Getting the most from Trip – highlighting two videos that give users – both new and experienced – to get better results from Trip

Subscribing to Trip

The difference between free and Pro Trip

Institutional subscriptions – the costs involved in obtaining institutional access


Understanding the full-text icons on Trip

Advanced search tip

Deleting ‘Recent’ search activity

Pyramids are back

Using Trip via mobiles or tablets


Adding new content to Trip

Journal coverage in Trip

Years covered by Trip

Sources searched by Trip – a bit dated with some content no longer available and other content added, but it still gives a good account of what we cover.

This blog will expand over time as relevant articles are added. If you’d like to suggest new topics to cover then please let us know via

Journal coverage in Trip

As well as our secondary evidence content, Trip also includes a large number of journal articles. The coverage is complicated and this post sets out what we include, journal wise, in Trip.

Key Primary Research: We include all the journal articles from the big 5 internal medicine journals – NEJM, Lancet, JAMA, BMJ and Annals of Internal Medicine. In addition we include all the content from the wonderful EvidenceAlerts.

PubMed’s core content: We include all the articles from PubMed’s core content (~110 journals)

Additional journal coverage: For our clinical areas (we have around 30 and cover topics such as cardiology, oncology) we selected the top journals based on Impact Factor for each area. These were then reviewed to ensure they were clinically focussed (many are at the academic scale of things, so these were excluded).

In total we grab all the articles from around 550 journals.

Randomised controlled trials (RCTs): We grab all the randomised controlled trials from ANY journal in PubMed (I believe they cover 5000 journals).

Systematic Reviews: As with RCTs we attempt to grab all the systematic reviews from PubMed. And we have a separate system to identify systematic reviews in non-PubMed journals.

In total we have approximately 4.5 million journal articles (compared to 33 million in PubMed).

Full-text: Final point! For Pro subscribers we offer links to full-text to approximately 70-75% of all our journal articles (~ 3.1-3.4 million articles).

Getting the most from Trip

Trip is well known for being easy to use. However, that doesn’t mean people don’t need a bit of ‘on boarding’ to help them get to grips with the site. To this end we’ve created two videos to help. The first, less than three minutes long, is a high-level take on Trip and should be enough to get people well versed in the basics. The second is longer and covers more ground.

  • An introduction to the Trip Database – covers the philosophy of Trip, basic searching, an overview of the results page, the use of colours and the evidence pyramid and how to restrict your search to specific evidence types e.g. systematic review or clinical guidelines.
  • Part 2: An introduction to the Trip Database – covers a brief history of Trip, the difference between ‘free’ and ‘Pro’, PICO and advanced searches, explaining results icons, exporting results and registering on Trip.

We hope you find them useful.

Remember, if you need additional help using Trip then reach out to us via, it may be for a specific query or possibly suggestions a new video topic.

Case studies of using Trip

Ahead of our 25th birthday later this year we thought it would be interesting to start collecting how users use Trip! This will be interesting for us at Trip to understand but it should be interesting for other Trip users to understand how others use the site.

So, we invite you to submit yours via We’re not expecting long essays, perhaps 1-3 paragraphs. Some great examples are below:

Example One, from a family physician in the USA

After reading an oncologist opinion suggesting that new diabetes in the elderly should prompt consideration of pancreatic cancer, I searched TRIP for information to both inform my background thinking and help me navigate between over-testing on the one hand and missing an important diagnosis on the other. TRIP seemed to afford the broadest search “net”, and a search with the terms “new onset diabetes pancreatic cancer” lead to two useful resources

  • A population study to characterize risk factors
  • The initial publication of a clinical risk model

Information from both articles has been directly useful in helping me think through with several patients whether their diabetes is likely “just diabetes” or might be a sign of something more sinister in need of further.

Example Two, from a medical student in Bosnia and Herzegovina

As a medical student interested in therapy comparison and evidence-based medicine, I find it very useful Trip Database’s PICO search tool which provides you with a very systematic and targeted search for papers. Moreover, I truly like that the research results are classified into different categories (e.g. systematic review, primary research, ongoing research, guidelines, etc.) as this makes trawling through the articles much easier.

Example Three, from a professor of dentistry in the USA

Trip and PubMed are the two database we teach to all our dental students and residents for the last 15-20 years. The students use Trip in both the classroom and clinic. It is great. It allows them to quickly keep up to date with the best evidence on patient care.

Thank you so much for developing this worldwide tool for healthcare.

Example Four, from a nurse and academic in Canada

I have been using it for many years (20+) and usually to support nursing students at a variety of academic centres in North America. I know from firsthand experience that many nursing students to whom I suggested using TRIP delivered discussion posts or assignment papers that clearly showed the influence of TRIP resource finding.

So, please, if you can share a case study, that’d be great and send them via

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