Clinical Queries – Diagnosis – Maximized Sensitivity – Ovid MEDLINE

Background

The Challenge: How to find useful information quickly?
Biomedical information repositories such as Ovid MEDLINE and Embase on Ovid, contain tens of millions of database records on past and currently available medical literature. Updated on a regular basis, they are large, diverse, highly structured and relentlessly dynamic general purpose resources. This can present challenges to health care professionals in clinical settings, for whom (a). only a sub-set of the database is relevant to them, and (b). they need to be able to quickly locate references that they can be sure are both clinically relevant and scientifically sound.

The Solution: Tested and trusted search filters
An important category of tried, tested and trusted database search filters are validated search filters. These are search strategies made available by subject matter and information experts who have constructed and developed them using a reference set of data as a ‘gold standard’. The resulting search filters are then tested against a test set of references in order to assess their effectiveness in terms of targeted and reliable information retrieval. Where they consistently exceed a certain threshold they are deemed ‘validated’. Although such search filters, as is here the case, may only be comprised of 4-6 search expression lines, the fact of their validation accords them a preferred status in terms of being an information retrieval option. In short, validated search filters are high quality, reliable ‘knowledge assists’ that help both clinicians and those that advise them on information retrieval matters, e.g. librarians and information specialists, to find useful information quickly.

The Source: Clinical Queries from McMaster University in Canada
As used here by Focused Searches, the phrase ‘clinical queries’ refers to database search filters that have been developed by the Health Information Research Unit (HIRU), based at McMaster University in Canada. Made available as part of their Hedges Project, the clinical query validated search filters cover dedicated ‘purpose categories’ surrounding human health disorders. The purpose categories are causation (etiology), course (prognosis), diagnosis, treatment and therapy, clinical predictions, the economics around human health disorders, studies of quality improvement of health services as well as continuing education of health care professionals. For fuller information on clinical queries, their origins as well as a list of accompanying references, please see  https://hiruweb.mcmaster.ca/hkr/hedges/ .

How to make best use of clinical queries?
This Focused Search presents the clinical query for the HIRU ‘purpose category’ Diagnosis, in three versions. The first version (see #1 in the table below), when used in combination with a human health disorder, has been tuned for maximized sensitivity. This is a broad search that will seek to return the highest proportion of relevant results pertaining to treatments and therapies related to the specified human health disorder. It may also include some less relevant results. By contrast its counterpart (see #2 in the table below) which is tuned for maximized specificity, constitutes a narrow search. It will seek to return the highest possible proportion of least relevant results. Being then such a targeted search, designed to include only the most relevant results, it may in doing so miss some of these otherwise wished for references. A third option (see #3 in the table below) is a search that has been tuned to seek a middle way between the broad and narrow search options, that is, to obtain the best balance between sensitivity and specificity.

CQ – Diagnosis - MEDLINE
Filter Type	Ovid Filter	Sens / spec / prec / acc(%)
1. Maximizes sensitivity	< Launch search on Ovid >	99 / 74 / 1 / 74
2. Maximizes specificity	< Launch search on Ovid >	65 / 98 / 11/ 98
3. Best balance of sensitivity and specificity	< Launch search on Ovid >	93 / 92 / 3 / 92

Adapted from https://hiruweb.mcmaster.ca/hkr/hedges/medline/

Are these search filters still up to date?
Yes, the clinical query validated search filters are up to date. For further information, please refer to the publications listed in Re: Search Filter - Currency: in the References section below.

Why does the Focus Search display as a list of search lines?
The format of the rendered Focused Search for this clinical query is in two parts. The first part is a single line which contains all the clinical query’s relevant terms and expressions. The second part splits the constituent terms and expressions into their component sub-parts and then lists these line by line. At the bottom of the list of component sub-parts the OR operator is then used to obtain an overall result for all the terms and expressions in combination. This result should always be the same as the very first line. The aim of unpacking the clinical query line by line in this way is to ensure the purpose behind each line is understood as is the Ovid syntax used in the line’s construction.

Ovid Syntax Check

• The expression ‘di.fs’ indicates a search on the MeSH subheading ‘diagnosis’, but as a floating subheading (.fs), i.e. not bound to a specific MeSH term.
• An .mp or ‘multi-purpose’ search, searches across a set of default fields for the database.
• ‘tw’ stands for ‘text word’, a field in Ovid MEDLINE covering both title (TI) and abstract (AB).
• The character ‘:’ is a wildcard denoting truncation. Ovid now more usually uses ‘$’ or ‘*’.
• Search lines can be connected one after the other using the OR operator. Alternatively the search line can be grouped together using the expression ‘or/2-4’ where ‘or’ refers to the OR operator and  the numbers 2-4 refer to the search lines #2, #3 and #4.

Search Stategy

Copy Strategy Launch Search

Reviewers

Primary: Michael Fanning

Secondary: Darlene Ennis

Review Date: 2024-07-15

Expiry Date: 2025-07-15

Original search produced by:

McMaster University

References:

Re: McMaster University, Health Information Research Unit, Hedges Project
For information on clinical queries, as well as a list of accompanying references, please see https://hiruweb.mcmaster.ca/hkr/hedges/

Re: Search Filter - Construction:
Haynes RB, Wilczynski NL. Optimal search strategies for retrieving scientifically strong studies of diagnosis from MEDLINE: analytical survey. BMJ. 2004;328:1040-2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC403841/

Re: Search Filter - Currency:
Navarro-Ruan T, Haynes RB. Preliminary comparison of the performance of the National Library of Medicine's systematic review publication type and the sensitive clinical queries filter for systematic reviews in PubMed. Journal of the Medical Library Association: JMLA. 2022 Jan 1;110(1):43. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8830395/

Wilczynski NL, McKibbon KA, Walter SD, Garg AX, Haynes RB. MEDLINE clinical queries are robust when searching in recent publishing years. Journal of the American Medical Informatics Association. 2013 Mar 1;20(2):363-8. Full text link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3638187/

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OvidGO! / Skills Videos
What is a bibliographic database?
What is the structure of a database?
What is Ovid MEDLINE?
What are Boolean Operators?
What are wildcards?
Subject heading searching

Citation:

OvidGO! Portal. Focused Searches: Clinical Queries – Diagnosis – Maximized Sensitivity – Ovid MEDLINE [Internet]. London (UK): Ovid Training Team (Editors); 2024 [updated 25 October 2024; cited 30 October 2024]. Available from: https://tools.ovid.com/ovidgo/searches/view.php?id=72