BDent1 - Finding the Best Evidence

BDent1 EBD: Finding the best evidence Jeremy Cullis Faculty Liaison Librarian (Dentistry) Dentistry Library University of Sydney Email: [email_address] Blog: http:// www.dentistrylibrary.blogspot.com

EBD: finding the best evidence

Aim of the session:

By the end of the session you will be

able to use a literature search to find the best evidence to

support decision-making in clinical situations and health care planning

Evidence-based dentistry (EBD) is an approach to oral health care that requires the judicious integration of systematic assessments of clinically relevant scientific evidence, relating to

the patient's oral and medical condition and history,

with the dentist's clinical expertise and the patient's treatment needs and preferences.

<http://www.ada.org/prof/resources/positions/statements/evidencebased.asp#definition >

Best evidence is:

Scientifically valid and clinically relevant research…into the accuracy of diagnostic tests, the power of prognostic markers, and the efficacy and safety of therapeutic, rehabilitative, and preventative regimes.

Straus et al, “Evidence based medicine…” 3 rd ed. 2005, p.1.

EBM or EBD – why do we need it?

“ My students are dismayed when I say to them “half of what you are taught as medical students will in 10 years have been shown to be wrong. And the trouble is, none of your teachers knows which half.”

Dr Sydney Burwell, Dean of Harvard Medical School, 1956, as cited by Straus et al, “Evidence based medicine…” 3 rd ed. 2005, p.31.

Constant need for valid up-to-date information

Traditional sources such as textbooks are out-of-date very quickly

Dentists are often time poor

No time to follow up questions

Need answers quickly

Need for quality information and synthesized evidence

The EBD process

Formulate an answerable question:

You have to make sure the question you are asking is specific and answerable.

This can help to:

Focus your information needs

Suggest effective search strategies

Formulating an answerable question

Use the PICO system

P opulation / Problem

I ntervention/ Exposure

C omparator

O utcome

Are school-based fluoride varnish programs effective in preventing approximal caries ?

Answerable question:

Population

In children with approximal caries

Intervention

Do school-based fluoride varnish programs

Comparator

No interventional programs

Outcome

Reduce the incidence of approximal caries

Types of clinical questions

Therapy or intervention questions

Prognosis questions

Aetiology or causation questions

Diagnosis questions

The most frequently asked questions are about diagnosis and therapy

Simple search strategy

P atient population/disease -> approximal caries

AND

I ntervention -> school-based programs AND fluoride varnish

(No comparator C or outcome O in this example)

Types of EBD Searches:

Finding systematic reviews:

Search the Cochrane Database of Systematic Reviews

Search in Medline then apply the EBM Reviews limit.

Limit Medline search to Meta analysis.pt .

B . Finding primary studies :

Search in Medline then apply a Clinical Queries Limit

What is a systematic review?

“… a summary of the medical literature that uses explicit methods to systematically search, critically appraise, and synthesize the world literature on a specific issue…Systematic reviews may, but need not, include some statistical method for combining the results of individual studies [meta-analyses].”

Straus et al, “Evidence based medicine…” 3 rd ed. 2005.

What is the

EBM Reviews: the Cochrane Database of Systematic Reviews?

A full-text database of the regularly updated systematic reviews of the effects of health care prepared by the Cochrane collaboration .

What is the EBM Reviews limit in Medline?

The EBM Reviews limit is a limit built into Medline which narrows your search result to studies which appear in one of the EBM Reviews databases:

EBM Reviews: the Cochrane database of Systematic Reviews : Consists of the full-text of regularly updated systematic reviews of the effects of health care (Therapy)

EBM Reviews: ACP Journal Club : consists of two electronic EBM journals: ACP Journal Club and Evidence- Based Medicine (All Question types)

EBM Reviews: Database of Abstracts of Reviews of Effectiveness (DARE): Abstracts of reviews performed by groups other than Cochrane groups (All Question types)

What if I can’t find a systematic review, or I need to find a primary study that is relevant to my question?

To find a Primary Study, use the Ovid Medline Clinical Queries Limits to limit your subject search.

Limits for the Four question types:

Therapy

Diagnosis

Aetiology

Prognosis

3 Levels of emphasis for each question:

Specificity (Narrowest)

Optimised

Sensitivity (Broadest)

Creating a search Strategy is one of the most important steps

What is your clinical question?

What are the three or four key concepts in your question?

Are there any similar words (synonyms) that describe each of the key concepts?

Are there any specific keywords that could limit your search?

How are you going to combine these keywords together to search?

[Search Strategy, Internet for Dentistry and Oral Health Available at: http://www.vts.intute.ac.uk/acl/tutorial?sid=1139338&op=preview&manifestid=210&itemid=12066 , Accessed 16 th of August, 2008]

Articles – Dentistry EBP (All available online) :

Sutherland, SE 2001, 'Evidence-based dentistry: Part I. Getting started .' Journal of the Canadian Dental Association , vol. 67, no. 4, pp. 204-6.

Sutherland, SE 2001, 'Evidence-based dentistry: Part II. Searching for answers to clinical questions: how to use MEDLINE ', Journal of the Canadian Dental Association , vol. 67, no. 5, pp. 277-80.

Sutherland, SE & Walker, S 2001, 'Evidence-based dentistry: Part III. Searching for answers to clinical questions: finding evidence on the Internet ', Journal of the Canadian Dental Association , vol. 67, no. 6, pp. 320-3.

Sutherland, SE 2001, 'Evidence-based dentistry: Part IV. Research design and levels of evidence', Journal of the Canadian Dental Association , vol. 67, no. 7, pp. 375-8.

Sutherland, SE 2001, 'Evidence-based dentistry: Part V. Critical appraisal of the dental literature: papers about therapy ', Journal of the Canadian Dental Association , vol. 67, no. 8, pp. 442-5.

Sutherland, SE 2001, 'Evidence-based Dentistry: Part VI. Critical Appraisal of the Dental Literature: Papers About Diagnosis, Etiology and Prognosis ', Journal of the Canadian Dental Association , vol. 67, no. 10, pp. 582-5.

Articles – EBM

Guyatt, GH, Sackett, DL & Cook, DJ 1993, 'Users' guides to the medical literature. II. How to use an article about therapy or prevention. A. Are the results of the study valid? Evidence-Based Medicine Working Group', JAMA , vol. 270, no. 21, pp. 2598-601.

---- 1994, 'Users' guides to the medical literature. II. How to use an article about therapy or prevention. B. What were the results and will they help me in caring for my patients? Evidence-Based Medicine Working Group', JAMA , vol. 271, no. 1, pp. 59-63.

Jaeschke, R, Guyatt, G & Sackett, DL 1994, 'Users' guides to the medical literature. III. How to use an article about a diagnostic test. A. Are the results of the study valid? Evidence-Based Medicine Working Group', JAMA , vol. 271, no. 5, pp. 389-91.

Jaeschke, R, Guyatt, GH & Sackett, DL 1994, 'Users' guides to the medical literature. III. How to use an article about a diagnostic test. B. What are the results and will they help me in caring for my patients? The Evidence-Based Medicine Working Group', JAMA , vol. 271, no. 9, pp. 703-7.

Laupacis, A, Wells, G, Richardson, WS & Tugwell, P 1994, 'Users' guides to the medical literature. V. How to use an article about prognosis. Evidence-Based Medicine Working Group', JAMA , vol. 272, no. 3, pp. 234-7.

Levine, M, Walter, S, Lee, H, Haines, T, Holbrook, A & Moyer, V 1994, 'Users' guides to the medical literature. IV. How to use an article about harm. Evidence-Based Medicine Working Group', JAMA , vol. 271, no. 20, pp. 1615-9.

Oxman, AD, Sackett, DL & Guyatt, GH 1993, 'Users' guides to the medical literature. I. How to get started. The Evidence-Based Medicine Working Group', JAMA , vol. 270, no. 17, pp. 2093-5.