Fine-tuning with subheadings: Searching for adverse effects and complications in Pubmed and SveMed+

The majority of all MeSH terms can be limited with subheadings. At present there are 83 subheadings. There are strict rules that decide which subheadings can be used with the different MeSH terms. Like the MeSH terms, subheadings are organised in hierarchical structures.  If you limit a MeSH term with a subheading in Pubmed or SveMed+, both will "be exploded", that is to say, you will get all the articles with the terms subordinate to the one you searched for. This also applies to the subheading.

But to get back to the subject  - in this case, adverse effects related to treatment methods or pharmaceutical preparations - the subheading "Adverse Effects" (AE) should be used in the search. Adverse effects often cause diseases or other problems - these causes can be searched out using the subheading "Etiology" (ET).

"Bleeding in the gastrointestinal tract after a gastric bypass operation"

Gastric Bypass/Adverse Effects
Gastrointestinal Hemorrhage/Etiology

"Drug allergy caused by antibiotics"

Anti-Bacterial Agents/Adverse Effects
Drug Hypersensitivity/Etiology

But can't diseases cause adverse effects? Well no, diseases can cause complications and secondary disease. I those cases you would use the subheading "Complications" (CO). Here's an example: to limit your search to articles that only deal with elderly people with bone fractures caused by osteoporosis, you use the subheading "Complications" (CO).  The complication causes "Etiology" (ET) an osteoporotic fracture.

"Bone fractures in elderly people with osteoporosis after falling"

Osteoporosis/Complications
Osteoporotic Fractures/Etiology

"Type 2 diabetes caused by morbid obesity"

Obesity, Morbid/Complications
Diabetes Mellitus, Type 2/Etiology

If you do not know exactly how the illnesses are linked and what causes what, then both diseases are given the subheading "Complications" (CO).

"Colonic disorders and helicobacter infection - which disease occurred first?"

Irritable Bowle Syndrome/Complications
Helicobacter Infections/Complications

How are subheadings used in Pubmed and SveMed+ from a purely technical point of view?

In Pubmed, there are several ways of limiting the search with subheadings. One way is to select Advanced search and then under All Fields scroll forward and choose MeSH terms. You write the term in the search field and click on Show index list to the right.

Then a list with the term will open up with all the permitted subheadings. Here you can also see how many articles there are in Pubmed with the specific term limited to each individual subheading. On Youtube you can see more about how Advanced search builder works.

Another way is to use MeSH Database to seek out the relevant MeSH terms and then limit by choosing one or more of the permitted subheadings. The search is built up with the help of Search builder. If you want to learn how you can use the MeSH database and subheadings, look at NLM's tutorial.

In SveMed+, click on the Advanced search tab and write in a term in the MeSH term field. When you have written in the term, you put a slash (/) directly after the last letter. Then all the possible subheadings will come up in a drop-down menu.

If you have any questions on how to search with subheadings please email ub@ki.se.

Klas Moberg

Librarian at KIB who works mostly with reading and indexing articles for the databases SveMed+ and Pubmed.