Science without sense…double nonsense

Píldoras sobre medicina basada en pruebas

Posts tagged HTA
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The hereafter

We have already seen in previous posts how to search for information in Pubmed in different ways, from the simplest, which is the simple search, to the advanced search methods and filtering  of results. Pubmed is, in my modest opinion, a very useful tool for professionals who have to look for biomedical information among the maelstrom of papers that are published daily.

However, Pubmed should not be our only search engine. Yes, ladies and gentlemen, not only does it turn out that there is life beyond Pubmed, but there is a lot of it and interesting.

The first engine I can think of because of the similarity to Pubmed is Embase. This is an Elsevier’s search engine that has about 32 million records of about 8500 journals from 95 countries. As with Pubmed, there are several search options that make it a versatile tool, something more specific for European studies and about drugs than Pubmed (or so they say). The usual when you want to do a thorough search is to use two databases, with the combination of Pubmed and Embase being frequent, since both search engines will provide us with records that the other search engine will not have indexed. The big drawback of Embase, especially when compared to Pubmed, is that its access is not free. Anyway, those who work in large health centers can have the luck to have a subscription paid through the library of the center.

Another useful tool is provided by the Cochrane Library, which includes multiple resources including the Cochrane Database of Systematic Reviews (CDSR), the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Methodology Register (CMR), the Database of Abstracts of Reviews (DARE), the Health Technology Assessment Database (HTA) and the NHS Economic Evaluation Database (EED). In addition, the Spanish-speakers can resort to the Cochrane Library Plus, which translates into Spanish the works of the Cochrane Library. Cochrane Plus is not free, but in Spain we enjoy a subscription that kindly pays us the Ministry of Health, Equality and Social Services.

And since we speak of resources in Spanish, let me bring the ember to my sardine and tell you two search engines that are very dear to me. The first is Epistemonikos, which is a source of systematic reviews and other types of scientific evidence. The second is Pediaclic, a search tool for child health information resources, which classifies the results into a series of categories such as systematic reviews, clinical practice guidelines, evidence-based summaries, and so on.

In fact, Epistemonikos and Pediaclic are meta-searchers. A meta-searcher is a tool that searches in a series of databases and not in a single indexed database like Pubmed or Embase.

There are many meta-search engines but, without a doubt, the king of all and one not to be missed is TRIP Database.

TRIP (Turning Research Into Practice) is a free-access meta-search engine that was created in 1997 to facilitate the search for information from evidence-based medicine databases, although it has evolved and nowadays also retrieves information from image banks , documents for patients, electronic textbooks and even Medline (Pubmed’s database). Let’s take a look at how it works.

In the first figure you can see the top of the TRIP home page. In the simplest form, we will select the link “Search” (it is the one that works by default when we open the page), we will write in the search window the English terms we want to search for and click on the magnifying glass on the right, with what the search engine will show us the list of results.

Although the latest version of TRIP includes a language selector, it is probably best to enter the terms in English in the search window, trying not to put more than two or three words to get the best results. Here we can use the same logical operators we saw in Pubmed (AND, OR and NOT), as well as the truncation operator “*”. In fact, if you type several words in a row, TRIP automatically includes the AND operator between them.

Next to “Search” you can see a link that says “PICO”. This opens a search menu in which we can select the four components of the structured clinical question separately: patients (P), intervention (I), comparison (C) and outcomes (O).

To the right there are two more links. “Advanced” allows advanced searches by fields of the record as the name of the journal, title, year, etc. “Recent” allows us to access the search history. The problem is that these two links are reserved in the latest versions for licensed users. In previous version of TRIP they were free, so I hope that this little flaw will not spread to the whole search engine and that, soon, TRIP will end up being a payment resource.

There are video tutorials available on the web of the search engine about the operation of the diverse modalities of TRIP; but the most attractive thing about TRIP is its way of ordering the results of the search, since it does so according to the source and the quality and the frequency of appearance of the search terms in the articles found. To the right of the screen you can see the list of results organized into a series of categories, such as systematic reviews, evidence-based medicine synopsis, clinical practice guidelines, clinical questions, Medline articles filtered through Clinical Queries, etc.

We can click on one of the categories and restrict the list of results. Once this is done, we can still restrict more the list based on subcategories. For example, if we select systematic reviews we can later restrict to only those of the Cochrane. The possibilities are many, so I invite you to try them.Let’s look at an example. If I write “asthma obesity children” in the search string, I get 1117 results and the list of resources sorted to the right, as you see in the second figure. If I now click on the index “sistematic review” and later on “Cochrane”, I’ll have a single result, although I’ll recover the rest just clicking any of the other categories. Have you ever seen such a combination of simplicity and power? In my humble opinion, with a decent management of Pubmed and the help of TRIP you can find everything you need, no matter how hidden.

And to finish today’s post, you’re going to allow me to ask you a favor: do not use Google to do medical searches or, at least, do not depend exclusively on Google, not even Google Scholar. This search engine is good for finding a restaurant or a hotel for holidays, but not for a controlled search for reliable and relevant medical information as we can do with other tools we have discussed. Of course, with the changes and evolutions that Google has accustomed us to, this may change over time and, maybe, in the future I will have to rewrite this post to recommend it (God forbid).

And here we will leave the topic of bibliographic searches. Needless to say, there are countless more search engines, which you can use the one you like the most or the one you have accessible on your computer or workplace. In some cases, as already mentioned, it is almost mandatory to use more than one, as in the case of systematic reviews, in which the two large ones (Pubmed and Embase) are often used and combined with Cochrane’s and some other that are specific for the subject matter. Because all the search engines we have seen are general, but there are specifics of nursing, psychology, physiotherapy, etc., as well as specific disease. For example, if you do a systematic review on a tropical disease it is advisable to use a specific subject database, such as LILACS, as well as local magazine searchers, if any. But that is another story…