by Cindy Schmidt, M.D., M.L.S.

updated August 2022

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Instructions:

1. This tutorial may NOT WORK PROPERLY IN INTERNET EXPLORER, Edge, or Google Chrome. Use Firefox or another browser. 

2. Use the Arrow icons below the instruction screen to go forwards and backwards in the tutorial.

3. If you want to skip between distant parts of the tutorial, you can use the "Menu/Contents" button above the instruction screen  to show the tutorial's "Table of Contents" and can click on the needed section of the tutorial.  If the "Contents" menu flickers or jitters, right-click on the light grey bar above the instruction screen and select the "refresh" or "reload" option.  Doing this one or more times should solve the problem.

4. Clicking the "Single-page view" link will produce a transcript of the entire tutorial.

Objectives

After completing this tutorial, the student will:

  • be familiar with The Cochrane Library, one of the resources frequently searched by those preparing formulary monographs.
  • know how to revise a PubMed, keyword search for use in the Cochrane Library
  • know how to designate the fields to be searched in The Cochrane Library
  • be familiar with the format of a Cochrane Review article and the features of a Cochrane Review that may be most helpful to the students
  • be familiar with the "Cochrane Trials" database

Activities Included in This Tutorial

  • Briefly review the content of the Cochrane Library so that you are aware of this resource in the future
  • Revise the PubMed tutorial keywords search for use in the Cochrane Library
  • Complete Cochrane Library exercises that will be graded via a Canvas quiz.

History -- Dr. Archibald Cochrane

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The Cochrane Library was named for Dr. Archie Cochrane, an early champion of systematic reviews and of meta-analyses.

Dr. Cochrane learned the value of evidence-based care during World War II.

While serving in the Allied forces, he was captured by the Germans. His experience as a prisonor-of-war-camp physician taught him that:

  • Doctors and their treatments are often unnecessary.

Dr. Cochrane often lacked access to the treatments that he would have prescribed in civilian life, but his fellow prisoners usually recovered anyway.

  • Only high quality clinical trials can provide the basis for scientifically justifiable treatments

Occasionally, Cochrane had access to more than one treatment but he rarely had any scientific data on which to base a treatment choice

 

History -- Dr. Archibald Cochrane

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Shortly before his 1988 death, Archie Cochrane wrote a forward for an Ob/Gyn text. In this forward, he urged the medical community to produce systematic reviews that would summarize all the high-quality evidence on important clinical questions. He emphasized that such reviews need to be updated on a regular basis.

Without such reviews, Cochrane said:

  • important effects of health care (good and bad) would not be identified promptly,
  • new research would duplicate old efforts
  • researchers and funding bodies would miss promising leads
  • people using health services would be ill-served

History -- Cochrane Collaborations

The Cochrane Collaborations were formed in 1992.

Members of the Cochrane Collaborations are experts who volunteer their time to write meta-analyses and systematic reviews in their areas of expertise. Together the members of a Cochrane Collaboration:

  • list the topics that are worthy of their attention,
  • create Cochrane protocols that guide the production of Cochrane reviews,
  • write Cochrane reviews
  • update or retire outdated Cochrane reviews

The Collaboration members work with paid editors who insure that writing quality and a uniform format are maintained.

The Cochrane Database of Systematic Reviews

The Cochrane Database of Systematic Reviews (CDSR) contains all the current and old versions of the protocols and reviews created by the Cochrane Collaborations.

The CDSR is published by Wiley and is one of several databases that are marketed together as the Cochrane Library.

The McGoogan Library pays a fee to license the Cochrane Library for on- and off-campus use by UNMC-affiliated individuals.

Why search the Cochrane Library?

  • To find high-quality systematic reviews
  • To complete the Searches Needed for a Systematic Review

Many journals require that authors of systematic reviews include a Cochrane Library search in their work (especially searches of the Cochrane Database of Systematic Reviews and The Cochrane Trials Database).

Because of the limited time available to you for this class project, we are not requiring a Cochrane Library or EMBASE search. If you were writing a document for publication or clinical use, you might be expected to complete keyword and subject headings searches in both databases.

Preparing to search the Cochrane Library

It's important to include keywords in a Cochrane Library search as this database includes unindexed records.  Also, one of the Cochrane Library databases, The Cochrane Trials database, includes records taken from other literature databases (PubMed/MEDLINE, EMBASE, etc.) and these records have been indexed with different subject heading systems. 

The PubMed tutorial that you completed earlier guided you through the steps involved in producing PubMed searches on the topic:

"How strong is the evidence supporting use of eculizumab (Solaris) in paroxysmal hemoglobinuria with thrombosis?"

After completing the PubMed lab, you had finished all the steps involved in producing:

1) a MeSH search for  trials.
2) a keyword search for unindexed records.
3) and, optionally, a keyword search for recent meta-analyses

When you completed the PubMed tutorial, you had revised the keyword search for use in searching Clinicaltrials.gov and/or EMBASE.  

You had removed the PubMed-specific tags (e.g. [tiab] tags) and filters.  These steps produced the following search strategy:

(Eculizumab* OR 219685-50-4 OR h5G1.1* OR h5g11 OR h5G1-1 OR 5G1.1 OR Soliris OR Elizaria OR Alexion OR Acveris ) AND (((intermittent OR paroxysmal ) AND ( haemoglobinur* OR hemoglobinur* OR haematur* OR hematur* OR haematinur* OR hematinur*)) OR PNH OR Marchiafava-Micheli) AND (Clot OR Clots OR budd-chiari OR embol* OR postthromb* OR thromb*)

Copy this strategy.  

Accessing The Cochrane Library

You should be viewing the Cochrane Library search page in an adjacent screen. 

Warning:  occasionally a partially functional version of the Cochrane Library will open.  If, during the course of this tutorial, you see an "Unlock abstract" or similar button, look for an "Open Athens" login or institutional login link.  You should be able to get to the fully functional version.

In the future, you will need to access the Cochrane Library using links on the Library's website.

To access Cochrane Library (or EMBASE or PubMed) from the Library Home page:

1. Click on "Literature Databases"

A screenshot shows use of the "Resources" menu to select "Literature databases"

2. Click on the relevant database link

3.  Login with your UNMC Net ID if asked to do so.

4. If you reach an error message or blank page, try refreshing the page or returning to the page  that contains the "Cochrane Library" link and clicking the link again.

There are also links to the Cochrane Library  on the homepage of the COP Research Guide (available through the Library link in Canvas).

Screenshot of Cochrane Library and EMBASE links on the COP Research Guide

 

Perform the Search

1) Paste your search statement into the Cochrane Library "Search" box.

screenshot of search box


2) Use the drop-down next to the search box to select the content you wish to search

(The default setting, "Title, Abstract, Keywords", usually retrieves all relevant results while avoiding retrieval of an overwhelming number of irrelevant results. Try this setting first. You can switch to the full-text option later if you initial search fails to retrieve results.)

 

4) Click the "magnifying glass" icon. 

If you happen to end up on the "Advanced Search" page, you will need to click the "Run Search" button  to make the results appear.

If you happen to end up on the "Search Manager" page, you will need to click the result number on the right-hand side of the page to make the results appear.

 

Features of the Result Page

 A screenshot shows the position of the tabs on the search results page.

  • The numbers of results in the various Cochrane Library databases are shown in the tabs above the search strategy (see green box in screenshot).
  • If the search retrieves any records from the Cochrane Database of Systematic Reviews (abbreviated name = "Cochrane Reviews") these will be shown by default, as seen in the figure above.
  • You could move to the results in a different database by clicking the tab for the database name, but at the moment we'll concentrate on the "Cochrane Database of Systematic Reviews "/"Cochrane Reviews" database. 
  • If more than one result is present, you can sort the results in different ways using the "Order by" menu above the result list to the left.

Focus on Cochrane Reviews/Cochrane Database of Systematic Reviews

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As you can see, the tutorial search produces 1 result for the "Cochrane Reviews" database.

This result is a full review (see review designation in the green oval in the figure).

A screenshot of the one Cochrane Reviews result.

 

Click on the title of the review "Eculizumab for treating patients with paroxysmal nocturnal hemoglobinuria" to see the review.

Focus on Cochrane Reviews/Cochrane Database of Systematic Reviews

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If you were writing a formulary monograph on our tutorial search topic (eculizumab use in PNH patients with thrombosis), you would want to pay special attention to the following aspects of this CDSR/Cochrane Reviews  article.  

  • The date when the review was published.

If the CDSR review is not recent, you might want to seek guidance from both the CDSR review and another, more recent, systematic review located by your PubMed search for indexed and unindexed systematic reviews.

Screenshot showing the "Published" date

 

There is a navigation box on the right-hand side of the page.  The "Abstract" is shown by defaultA screenshot of the "Contents" panel.

 
  • Click on the "Background" line in the navigation box.  If you were writing a systematic review on use of eculizumab in PNH, this section might help you decide what topics should receive attention in your background/introduction section.
  • Next, click on "Methods." The "Methods" section includes descriptions of search strategies,  inclusion/exclusion criteria, and outcomes of interest.  At the very least, this section of the CDSR review would give you an idea of the outcomes worthy of consideration in your formulary monograph.
  • Click on "Results."  The "Results" section provides information about  the findings of the critical review of the articles identified by the CDSR authors' searches,  reasons for exclusion of some articles,  the evaluation of bias of the included articles, and evaluation of the effect of the intervention.  You would want to see how your decisions about article quality and bias compare to those of the CDSR authors.
  • The "Authors' Conclusions" are divided into "Implications for Practice" and "Implications for Research."  You would want to decide whether you agreed with the CDSR authors' conclusions.
  • The "Data and Analyses" and "Figures and Tables" sections (see figure below) provide links to tables and graphs.  You might find these helpful when considering the merits of the author's conclusions.

A screenshot showing the location of the "data and analyses " link.

Focus on Cochrane Reviews/Cochrane Database of Systematic Reviews

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Scan the relevant sections of the CDSR article  to find answers to the questions below.

The following questions are part of your Canvas-based quiz. You can either record the answers now and enter them in Canvas later, or you can open a new tab or window, go to Canvas and enter answers as you progress through the tutorial .

1. Studies were only considered for review if they were randomized controlled trials published in peer-reviewed journals.

Hint:  "types of studies" included, inclusion criteria, search strategies, etc. are described in the "Methods."

2. Which of the following diagnostic criteria were used to determine whether patients would be included?

3.  Was the database "International Pharmaceutical Abstracts" included among the databases searched for relevant articles?

4.  According to the flow chart, 4161 database records were reviewed.  How many trials met the inclusion criteria for this Cochrane Review?

Hint:  Look at the "Figures and Tables"

5.  Do the authors recommend use of eculizumab in PNH patients?

  • Please also note the search strategies included in Appendices 2 - 5. The location may vary, but the search strategies will be shown in every CDSR review and in some Cochrane protocol.

Return to the "Advanced Search" page

Let's move on to briefly consider the search results from other Cochrane Library databases.

To return to the Cochrane Library search results page, click on the "Search" or "Advanced Search" or "Search Manager" browser tab.

A screenshot showing the "Advanced search" tab

"Cochrane Protocols" (Cochrane Reviews in progress)

 If you write a systematic review or prepare a formulary monograph and include a Cochrane Library search, be sure to check the "Cochrane Protocols" tab.  A Cochrane protocol can be quite helpful to those writing a systematic review on a similar topic.

A screenshot showing the position of the "protocols" tab.

A Cochrane protocol is created at the beginning of the process of writing a Cochrane systematic review. The authors:

  • describe the issue to be studied,
  • list the interventions and outcomes of interest,
  • outline the criteria for including or excluding a study from their review, and,
  • frequently, list the search strategies that will be used

Full reviews are, of course, more useful.

Full reviews include:

  • all the information included in the protocol,
  • lists of the articles included and excluded from the review
  • reasons for inclusion or exclusion,
  • results of tests for bias,
  • analyses of the combined data if possible, and
  • conclusions for research and practice

Cochrane Library "Trials" Database

 

Let's now move on to the The Cochrane Library's "Trials" database.  This database  is also known as the "Cochrane Central Registry of Controlled Trials". 

The "Trials" database is maintained to support production of Cochrane Reviews. Records are obtained from many sources, e.g. PubMed, EMBASE, ClinicalTrials.gov, meeting proceedings, etc..

To reach the search results in the "Trials" database:

  • Click the "Trials" tab.

A screenshot shows the position f the "trials" tab.

  • Use the "Order by" menu to select the "Year first published -- New to Old.."
A screenshot show selection of the "Year first published -- New to Old..." option
  • Use the "Results per page" menu (on the right-hand side of the page) to select the "100" option so that you can see all search results on a single page.
A screenshot of the "results per page" menu

"Cochrane Trials" record types -- Clinical Trial Registry records

As mentioned earlier, the Cochrane Central Register of Controlled Trials (abbreviated "Cochrane Trials") contains records for a variety of different sources. 

 

Clinical Trial Registry records

Many of "Cochrane Trials" records provide links to descriptions of ongoing trials that have been entered in clinical trial registries.  To see the records that correspond to trials registered with the US government's clinical trials registry, ClinicalTrials.gov:

  • Open your browser's find feature (Command-f on a Mac or Control-f on a Windows machine)
  • Look for instances of --

https://clinicaltrials.gov

There were about 2 clinicaltrials.gov records included among the 83 "Cochrane Trials" search results when this tutorial was last updated.  There were another 6 records from the World Health Organization's trial registry (web address prefix =  https://trialsearch.who.int )

 

"Cochrane Trials" record types -- Conference Abstracts

Many  "Cochrane Trials" records contain conference abstracts.   New scientific findings are often presented in  posters and presentations at scientific meetings before they are disseminated in published journal articles.   The Cochrane Trials database and EMBASE are the two databases licensed by UNMC that will be most helpful if you need to find information presented at scientific meetings.

The abstract is often the only section of a conference poster or presentation that is published. So, the information in the Cochrane Trials or EMBASE record is usually the only information available (there's no corresponding full-text article for most of these conference presentation/poster records).

The part of a "Cochrane Trials" record shown on the search results page may not tell you whether an the item represented is a conference abstract or a full journal article.   

  • Find the "Cochrane Trials" record for "Predictors for improvement in patient-reported outcomes: post hoc analysis of a phase 3 randomised, open-label study of eculizumab and ravulizumab in complement inhibitor-naïve patients with paroxysmal nocturnal haemoglobinuria ( PNH )" published in 2022. 

The record for PR033 cost-utility analysis....

In this record, there are clues that this item is conference abstract.   The article is in "Suppl 1" of volume 197.  Journal supplements often contain conference proceedings.  The item is only a single page long.  It begins on page 136 and extends to page 137.  To determine whether a "Cochrane Trials" record does, in fact, represent a conference abstract,

  • click on the title
  • scroll down below the abstract to find the "Information" section.
  • look for a "Conference Details" area and/or a "Conference Abstract" entry in the "Publication type" area.
The "Information" section of the detailed record. "Conference Details" is underlined.
 
Scan the abstract .  The following questions are part of your Canvas-based quiz. You can either record the answers now and enter them in Canvas later, or you can open a new tab or window, go to Canvas and enter answers as you progress through the tutorial :
 

6.  When you want to know what's being discussed at scientific conferences before the findings are published in journal article form, which databases should you search?

 
 

7.  Use the browser's find feature to look for instances of the letters thromb

Are post-eculizumab thrombosis rates discussed in this abstract?

 
 

8.  Based on this study, which of the following lab values is more closely correlated with quality of life in PNH patients?

When this tutorial was last updated (August 2024), many, perhaps most, of the items retrieved by the search were records for conference abstracts. 
 
It's important to notice whether an item of interest is a conference abstract or a regular journal article. 
  • Conference abstracts have not been subjected to rigorous peer review. 
  • When an item is a conference abstract, the information in the "Cochrane Trials" record is all that is available in that journal issue.  If a full-text article exists concerning the study discussed in the abstract, that article would be published in a different journal issue or, potentially, a different journal.  It may have a different article title and may even have a somewhat different list of authors.

"Cochrane Trials" record types -- Journal Articles

 Some of "Cochrane Trials" records represent full journal articles. 
  • Find the article entitled

Long-term safety and efficacy of sustained eculizumab treatment in patients with paroxysmal nocturnal haemoglobinuria

 

published in

British Journal of Haematology, 2013, volume 162, issue 1

screenshot of record for British Journal of Haematology article

  • Click on the article title to see the detailed record.
  • If you scroll down to the "Information" section, you will see that the "Publication type" is "Journal article."
  • If this article was of interest to you, you would want to see the full-text

Cochrane Trials -- full-text access

There are several paths to full-text.  Not all paths are present in all records.

A screenshot of a "Cochrane Trials" record for a journal article shows the doi and EMBASE links.

  • Method 1: DOI
    • click on the doi link (green arrow in screenshot above)  
    • Look for "Open Athens" or "institutional" logins if asked to login.
  • Method 2:  Library Catalog.
    • Open a new browser tab and use it to go to the Library's homepage.
Screenshot of the Electroic Journal Finder
    • Click the "Resources" menu located above the picture.
    • Click on the "Library Catalog" option
    •  Search for the journal's title.
    •  If a source for online access is located, click the link to that source. 
    • Search the journal's/journal vendor's website for the article title.
  • Method 4:  Google Scholar
    • If you haven't set Google Scholar to show "GetIt@UNMC" links, start by doing so.
      • Go to scholar.google.com
      • Click on the "menu" icon (a stack of several horizontol bars)
      • Click on the cogwhell/settings icon
      • Click on "Library Links"
      • Search for UNMC, select our library's links
      • Click the "Save" button
        Screenshot of the "Library Links" page.
    • Copy the article title of interest from the Cochrane Trials result page.
    • In Google Scholar,  type a quote (") in the search box, paste in the article title,  type a closing quote, and hit the "Enter" key on your keyboard
    • A "hit" for the article of interest will usually appear. 
    • Look to the right of the "Hit" .  Links to freely available full-text and "GetIt@UNMC" links appear in this position.
Screenshot of Google Scholar hit with "GetIt@UNMC" link on the right.
 
 

9. Which of the methods below will be useful when looking for the full text version of an article identified by a Cochrane Trials record? Assume that UNMC licenses the full-text version.

Congratulations! Time for the Canvas Quiz

 Congratulations!  You've finished the tutorial.  Please, use the answers you recorded while completing the tutorial to complete the Quiz available through the "Cochrane Library and EMBASE Tutorial and Quiz" link in Canvas.