Strategies for Searching the Literature Using PubMed
Course Number: 340
Course Contents
PubMed Clinical Queries in Action
To further demonstrate searching with PubMed Clinical Queries let’s review a second case scenario.
Case Scenario #2 Eric is a twenty-seven-year-old bartender who has used chewing tobacco for 9 years. He is a frequent user who chews almost five hours a day. Eric knows he can’t quit by will power alone because he has tried in the past. He wants to know if using a nicotine patch rather than behavioral counseling can help him permanently quit.
To locate the highest level of evidence, begin with the Clinical Queries feature (Figure 17) by typing in the main problem of interest, chewing tobacco cessation. In this case we also will combine it with the Intervention, nicotine patch, and the Comparison, behavior counseling, using the "and" Boolean operator.
Figure 17. Search Results for Chewing Tobacco Cessation, Nicotine Patch and Behavior Counseling.
Figure 17. Search Results for Chewing Tobacco Cessation, Nicotine Patch and Behavior Counseling.
The results of the search identified 33 citations under Clinical Study Categories, the Broad Scope and 18 under the Narrow Scope.
In reviewing the title of the citations it should occur to the user that perhaps ‘chewing tobacco’ is not the correct indexing term since ‘smokeless tobacco’ is used and nowhere is ‘chewing tobacco’ used in the title of any citation. In this case, you should search the MeSH Database to determine the correct term. You discover that the MeSH term for chewing tobacco is smokeless tobacco and see that it is the correct indexing term in the MeSH hierarchy (Figure 18a). Searching for smokeless tobacco cessation (using the correct MeSH term from chewing tobacco) results in the MeSH term Tobacco Use Cessation (Figure 18b).
Figure 18a. MeSH Database Search for Chewing Tobacco.
Figure 18b. MeSH Database Search for Smokeless Tobacco Cessation.
The MeSH term for nicotine patch is Tobacco Use Cessation Devices and is a new MeSH term introduced in 2019 (Figure 18c). Finally Behavioral Counseling is not a MeSH term and typing counseling provides several options to choose from (Figure 18d.). Directive Counseling is probably the closest definition to what we are investigating for Eric. However, we can see that it is indexed under Counseling and for this search we select Counseling as the MeSH term to capture a broader scope in potential relevant articles (Figure 18e).
Figure 18c. MeSH Database Search for Nicotine Patch.
Figure 18d. MeSH Database Search for Counseling.
Figure 18e. MeSH Database Description for Directive Counseling.
A new search can be generated right from the MeSH database by adding MeSH terms to the search builder as you explore terms. This is done by selecting the search term (if there is more than one listed) and clicking on the Add to search builder button on the right side of the screen. Terms can be combined with the Boolean operators AND/OR/NOT and a search can be generated (Figure 19a). When all of the terms are added, and combined with your choice of Boolean operator, click on Search Pubmed (Figure 19b.) Based on the MeSH terms a new search query is run and 3 potentially relevant citations are identified (Figure 19c.). The search query can be highlighted and copied using CTRL+C and pasted into clinical queries as well for the same results (Figure 19d).
Figure 19a. PubMed Search Builder in MeSH Database.
Figure 19b. PubMed Search Builder with MeSH terms for Eric.
Figure 19c. PubMed Results of Search for Smokeless Tobacco AND Tobacco Use Cessation AND Tobacco Use Cessation Devices AND Counseling.
Figure 19d. Clinical Queries Results of Search for Smokeless Tobacco AND Tobacco Use Cessation AND Tobacco Use Cessation Devices AND Counseling.
As demonstrated, there is no one correct way to conduct a search and for someone who is not familiar with Boolean operators and combining terms, the filters feature or the MeSH database, so the Clinical Queries feature is an excellent starting point. For example, if the Clinical Queries search just included “chewing tobacco cessation,” 840 citations are identified (Figure 20). Changing the search to include the MeSH terms, Tobacco Use Cessation AND Smokeless Tobacco results in 109 or 32 citations broad/narrow respectively (Figure 21.). However, all of these do not necessarily focus the search on the chief concern of Eric, which is the effectiveness of the nicotine patch as compared to behavioral counseling on quitting chewing tobacco.
Figure 20. Results of Clinical Queries Search for Tobacco Use Cessation.
Figure 21. Results of Clinical Queries Search for MeSH terms Tobacco Use Cessation AND Smokeless Tobacco.
Figure 21. Results of Clinical Queries Search for MeSH terms Tobacco Use Cessation AND Smokeless Tobacco.
To narrow the 109 or 32 citations, scan down the page and click on See all (109) or See all (32) to apply filters. It brings up all 109/32 citations on the Results page and by selecting the Publication dates filter, you can identify those published within the last 5 years, narrowing the results from 109 to 14 citations (Figure 22). Adding article type filters, one is a meta-analysis (Figure 23.) and two are systematic reviews (Figure 24.). However, there’s no guarantee that any of the abstracts address the real problem of whether a nicotine patch will be more effective than behavioral counseling in helping Eric permanently quit using smokeless tobacco.
Figure 22. Clinical Queries Search Results with 5 Year Limit.
Figure 23. Clinical Queries Search Results with 5 Year Limit and Meta-Analysis Filter.
Figure 24. Results of Clinical Queries Search Filter 5 year limit and Systematic Reviews.