This course presents a brief overview of evidence based
health care with some dental examples. The emphasis will be on how to search
for articles using two free electronic databases Cochrane Library and PubMed.
If you are a University of Adelaide student or staff member
and have any difficulties please contact me.
Mick Draper
Telephone
830 35335
Internal extension
35335
Email
michael.draper@adelaide.edu.au
Evidence Based
Health Care is (perhaps) a new paradigm in providing
objective health care.
Free access to databases such as Cochrane
Library, and PubMed,
plus cheap computers
have made it possible for practitioners to search
for outcomes based, objective research, and apply
the results to their patient populations.
It's also possible for patients to find a lot of information on many medical conditions. Patients may find information online and ask practitioners for their opinions.
Show me the evidence
Uni of Adelaide community can click here to read
Rachel C Vreeman, & Aaron E Carroll 2007. Medical myths BMJ 335:1288-1289 (22 December)
The authors examine the evidence for 7 commonly quoted medical myths
History of Evidence Based Practice
Evidence based practice comes from three approaches to medical practice that were used in the late 18th and early 19th centuries.
The Clinical Methods approach was to use received wisdom, experience, anecdote, and observation to decide how to proceed in each case.
The Pathophysiology approach was based on laboratory investigation and theoretical extension to practice. This was developed by Claude Bernard who thought that a scientific approach was the way forward. He thought that understanding the science of pathology would provide cures or prevention methods for many diseases. This is the method taught by med schools during most of the second half of the 20th century and was the received wisdom of that era.
The Epidemiological or Numerical approach was championed by Pierre Louis. He felt that received wisdom wasn't working for treatment of infectious diseases. He stated that ‘a therapeutic agent cannot be employed with any discrimination or probability of success in a given case, unless its general efficacy in analogous cases, has been previously ascertained’.
Pierre Louis is famous for challenging bleeding as a treatment for typhoid. Pathophysiologists noted that inflammation was associated with increased blood flow, and concluded that bleeding would be therapeutic! Louis’ numbers showed that bleeding didn't work. This also produced hostility as practitioners didn't want to treat their patients based on 'somebody else's numbers'.
Louis was only partially successful, but developments in the late 20th century in Britain and Canada increased the profile of clinical epidemiology.
Click here for an article on the history of evidence based practice. It describes the history of the three approaches to medicine in Europe in the 19th century and developments in the 20th century.
Swales, J. 2000. The troublesome search for evidence: three cultures in need of integration. Journal of the Royal Society of Medicine93 402-407.
Recent History of Evidence Based Practice
In Britain, Archie Cochrane worked on the health services provided to Welsh miners. He felt that the health care was inadequate and inconsistent. He looked for a method of evaluating health care and decided that randomized controlled trials were most useful because they reduced the bias that hindered other methods. Cochrane's ideal was for each specialty to produce a series of meta-analyses of all the trials in the discipline, and to regularly update these meta-analyses.
Definition of Meta-analysis
The process or technique of synthesizing research results by using various statistical methods to retrieve, select, and combine results from previous separate but related studies. From answers.com
A statistical method of combining the results of a number of different studies in order to provide a larger sample size for evaluation and to produce a stronger conclusion than can be provided by any single study. From GreenFacts.org
At McMaster University David Sackett founded the world's first department of clinical epidemiology. He and his colleagues compiled the evidence from trials as an aid to practitioners and policy makers. This led to examination of the costs involved in the treatments for various conditions, providing evidence for governments to decide how best to spend taxes in health care.
In 1991 the ACP journal club was launched by the American College of Physicians to provide practitioners with new evidence and its evaluation.
In 1995 the journal Evidence based medicine was launched on cd-rom and from 2000 was available as EBM online.
In 1988 the Oxford Database of Perinatal Trials was launched. This database collected evidence from many trials and synthesized the results in a single database. This developed into the Cochrane Collaboration and its Cochrane Library, a dynamic form of publication where authors publish systematic reviews on interventions and are required to keep the reviews updated as new evidence becomes available. Chronology of The Cochrane Collaboration
Cochrane Oral Health Group Abstracts
Abstracts of Cochrane Reviews from this group.
This is the quick way to check on Cochrane oral health systematic reviews.
Click on the button below to open this web site in a new window.
The Value of Randomized Controlled Trials
RCT's reduce the bias in testing treatments in clinical research. With neither practitioners or patients knowing who is receiving treatment and who is part of the control group much of the bias in testing interventions can be removed.
The value of randomized controlled trials was dramatically shown in testing of anti-arrhythmic drugs. Anti-arrhythmic drugs were used well into the 20th cent to treat ventricular extrasystole following myocardial infarction. A trial of these drugs was stopped when the test group showed higher mortality than the controls. PubMed record
There is still a gap between clinicians who are taught medical science and the need for being aware of individual biology, and those who use the tools of epidemiology such as the randomized controlled trial, and meta-analysis. In the 1960's Alvan Feinstein was concerned about the number of articles presented to conferences of clinical bodies in the USA that were on nonhuman, nondisease clinical research. He accused medical science institutions of being preoccupied with rat turd grinding in the lab. Feinstein applied mathematical techniques to clinical medicine. His many works focused on the goals and the methods required for effective clinical medicine that went beyond received wisdom from laboratory studies.
Evidence based practice should incorporate having the best available evidence, using clinical judgment based on the experience of the practitioner, being patient centred and continuing the evaluation and improvement of the processesof clinical practice
Definitions of Evidence Based Practice
Evidence based practice is ... The conscientious, explicit, and judicious use of current best evidence in decision making. It customizes worker experience with the various forms of evidence to the specific problem/situation under investigation. (Sackett, et al, 1997).
Evidence-based practice is "a total process beginning with knowing what clinical questions to ask, how to find the best practice, and how to critically appraise the evidence for validity and applicability to the particular care situation. The best evidence then must be applied by a clinician with expertise in considering the patient's unique values and needs. The final aspect of the process is evaluation of the effectiveness of care and the continual improvement of the process" (DePalma, JA 2000 Evidence-based clinical practice guidelines. Seminars in perioperative nursing9(3) 115-120.)
"Evidence based clinical practice is an approach to decision making in which the clinician uses the best evidence available, in consultation with the patient, to decide upon the option which suits that patient best". Source: Muir Gray JA. (1997) Evidence-based healthcare: how to make health policy and management decisions. London: Churchill Livingstone.
While these definitions are directed at the practitioner-patient relationship, you can see from the figures below why policy makers might be interested in EBP if it can reduce expenditure and stop useless or harmful treatment.
Trends in Australia's Health Expenditure
Date
Total Expenditure
(Aust$Billions)
% of GDP
Total Expenditure per Person
Aust $
2003/04
78.6
9.7
3,931
1993/94
36.9
8.3
2,049
1983/84
14.9
7.3
966
1973/74
3.1
5.5
231
Australia's expenditure on health has increased above the average of the OECD countries in the period 1993/94 to 2003/04
Need for objectivity and evidence of effectiveness in
clinical practice
Geographical variation in interventions
Need to cease ineffective treatments to contain costs
to national health systems and patients
Need to move from practitioner oriented outcomes to patient
oriented outcomes
Skills Required for Evidence
Based Practice
1 Acknowledge information gaps
2 Formulate answerable questions to
fill gaps
3 Know the sources of evidence
4 Know how to search sources
5 Quickly assess the usefulness of
information
6 Critically read the literature/Evaluate
clinical guidelines
7 Integrate best evidence, and clinical
judgment for the benefit of
individual
patients
8 Without bias, present intervention options to patients
9 Evaluate and record the effectiveness of the whole process
Sites for Learning Evidence Based Practice Introduction to Information Mastery
A significant online course covering clinical questions and how to read different types of articles. From Department of Family Practice College of Human Medicine Michigan State University.
Know the limitations of evidence
based health care
There may not be any information on a topic, or the evidence may only be at case level
The populations tested may not share the
same characteristics as your patients.
The patients in the trials may not have been compliant.
The methods used might not always be appropriate
The conclusions of the authors might not always match their results.
The time required to become efficient at evidence based practice might be daunting.
Time and Skill Constraints
Practitioners have only a few minutes each day for reading
PubMed has 17 million+
refs to search
Unpracticed users of Medline/PubMed can take more than 30 minutes to search
The relevance of many of the references can be low
Most practitioners are willing to learn the skills
required to perform quick effective searches, but often don't have time
to use them. Many busy practitioners prefer to use a product that regularly
updates the best practice for particular conditions.
There are subscription services that provide up to date best practice
information. The University of Adelaide
Library has access to MD Consult. This database includes searchable clinical ebooks, ejournals, review journals, a drugs database, news, practice
guidelines, patient handouts, and cases on a wide area of clinic medicine. Other services include
The ability to acknowledge a gap in your knowledge
is a clinical skill.
Do you know enough about diagnosis, & intervention
for a condition, as presented, to manage the patient to the best outcome?
Do you know what you don't know?
2. Formulating
Questions
If you ask the wrong questions you may be flooded with
information, or find nothing relevant to your patients.
Do you need to get evidence that relates exactly to your
patient or group of patients, or all the evidence that relates to all patient
groups? (age, sex, ethnicity, medically compromised, outcome desired by patient)
What sorts of intervention can you provide, what sorts
of interventions will need referral?
Do you need to compare different interventions?
PICO Principle To help formulate questions and begin to produce a search
strategy it can be useful to use the PICO method. This focuses your thoughts
on the concepts that you need to include in your searches. Most evidence
based practice questions can be formulated in 4 parts.
Population(s), patient(s), participants,or problem(s)
Who are the patients? What is the
clinical problem or concern with this patient?
Consider the conditions they suffer, their age,
ethnicity, gender, geographical location etc.
Are you interested in therapy, diagnosis,
aetiology, prognosis, prevention, or education
Are there co existing problems?
Has the patient been exposed to a
harmful agent? (drugs, pollutants, poisons)
Interventions or indicators
What is the intervention, diagnostic test,
exposure, prognostic factor?
What do you want to do for the patient?
Prescribe a drug, run a diagnostic test, or use surgery?
Comparator(s) or control(s)
Do you want to
compare two interventions, a drug and placebo, intervention and no treatment, two or more diagnostic tests?
You might not
always need to include comparison in your search.
Outcome
What outcome
are you trying to achieve, measure, prevent or avoid?
(relieve
symptoms, restore or improve function, prevent or reduce the number of
events) You don't need to include a particular outcome if you are looking for all
outcomes of a particular set of interventions.
halitosis
chlorhexidine + Zn
Listerine
volatile sulphur compounds
bad breath
essential oil mouth wash
volatile sulfur compounds
oral malodour
oral flora
oral malodor
patient satisfaction
Here are 3 web sites that might help with using PICO. Formulating Patient Centered Questions
From The Library of the University of Illinois at Chicago
The Well Built Clinical Question
from Duke University Medical Center Library and Health Sciences
Library, UNC-Chapel Hill
Focusing Clinical Questions
from Centre for Evidence Based Medicine
3. Sources of
Evidence
Textbooks
Textbooks can be out of date when published.
Textbooks often include 'established
knowledge' that doesn't change (much) such as anatomy, physical
properties of dental materials, drug adverse effects.
Texts can sometimes provide useful summaries.
Electronic textbooks These are designed to overcome the problem of being out
of date and having insufficient citations for readers to locate original
articles.
Here are 2 online books held by The University of Adelaide
Library
Harrison's On Line The online version of
Evidence based
practice journals There are now more journals that are specifically aimed
at evidence based practice.
Bandolier including Bandolier Learning Zone with info on how to understand clinical trials, statistics, clinical guidelines, and articles (including Bisphosphonates and jaw osteonecrosis)
Personal collection
Most practitioners will keep an electronic and/or paper
collection of books, reprints, and other material used in everyday practice.
The University of Adelaide community has access to a site licence for the
bibliographic database management system called EndNote. You can get information
on where to get this and how to use it from the
University of Adelaide
Library EndNote site.
Article types and their usefulness
for evidence based health care
Laboratory experiments While test tube experiments are
essential in all areas of medicine including dentistry, clinicians can't
base treatment on the results.
Animal experiments Some useful result have come from
animal experiments, and while these may indicate the usefulness of human
trials, clinicians can't use these articles.
Case reports These are often memorable and can
serve as a reminder for diagnosis and treatment, but you can't base a practice
on small populations (1 patient) where bias may be present.
Phase I trials
Usually conducted on small numbers
of healthy volunteers to look for adverse effects. These results aren't
appropriate for clinicians working with patients. These trials don't always go to plan e.g. TGN1412.
Phase II trials (Case Series)
Mostly these use small numbers
of selected patients, or a series of patients often without a control group
to test the outcome of an intervention. Results of Phase II Trials are
not usually considered sufficiently objective and rigorous enough to use
in clinical decisions.
Phase
II trial of Viagra (Sildenafil) as an antihypertensive agent in mature
patients.
Phase III trials
Large long term trials on patients,
usually with randomized control, double or single blinding, control groups,
placebos etc. These trials can be used to make clinical decisions.
Phase IV trials These are usually post marketing trials on very large
numbers of patients to gauge the long term safety and find rare adverse
effects of interventions. Useful for clinical decision making.
Systematic Reviews These are peer reviewed articles
that bring together all the objective studies on interventions for particular
conditions. Sometimes authors do this to compare interventions, and sometimes
to join study results to increase the size of the population tested. If
the original articles are not randomized controlled trials, then the authors
should explain why they are used in the analysis and what adjustments were
made in the statistical analysis to include them. These are useful for
clinical decisions, often called the gold standard.
Cohort Studies Patients with a particular condition are followed over
time and compared with a control group. Cohort studies aren't as reliable
as controlled trials but are useful in situations where it wouldn't be
ethical to run a randomized trial. Types of cohort studies include
Longitudinal Studies where particular groups or individuals
within a cohort are studied.
Follow-up Studies study the effect of exposures, procedures,
or characteristics such as a disease.
Prospective Studies study the incidence or mortality
of subgroups after their selection.
Cohort studies can be used for making clinical decisions.
Clinical Practice Guidelines Should be evidence based serial statements to assist
in diagnosis and treatment of particular conditions. Care should be taken
to ensure that these are NOT based only on expert opinion. Look carefully
at the evidence summary to ensure that the evidence is both comprehensive
and up to date. You'll also need to see if it's possible to follow through
with the guideline in your situation. Find out how good the evidence is
for each step of the guideline.
Guidelines
for the removal of wisdom teeth From NICE (National Institute for Clinical
Evidence UK)
Dental
Check-ups NICE Guideline.
What type of study will (best) answer your question?
Clinical examination
Prospective
Diagnostic testing
Prospective
Prognosis
Cohort Study>Case Control >Case Series
Therapy
RCT
Aetiology or Harm
Cohort Study>Case Control>Case Series
Prevention
RCT>Cohort Study>Case Control>Case Series
Cost
Economic analysis
From Duke University Medical Center Library
4. Know how to search sources
This will be the focus of our hands
on sessions where we'll use Cochrane Library, and PubMed.
5 - 6. Assessing
the literature
This will be covered by other parts
of your course. You should develop the ability to quickly decide if an
article is worth reading.
Quickly find out
Does this article show a significant
useful clinical effect?
If not, dismiss the article for your purpose.
If it does, you need to ensure that the result is
objective.
Is this article applicable to your patients?
Is the intervention feasible?
A free online course on Epidemiology and Biostatistics from Tufts University.
Tufts state that (t)his course teaches the basic skills needed to critique the medical literature
by providing a fundamental understanding of epidemiology and biostatistics.
Articles on appraisal The
Consort Statement A checklist and flow diagram to help improve
the quality of reports of
randomized controlled trials. It's also useful for those assessing
such articles. All reports of rct's should have at least the mininum set of recommendations listed in the statement
Trisha Greenhalgh's series of articles called How
to read a paper.
Barr Smith Library has the 3 editions of Greenhalg's book How to read a paper: the basics of evidence-based medicine. The third edition is in the Main Collection of the Library at 616 G813h.3
Susan E. Sutherland has written several articles on finding
and assessing literature on evidence based dentistry. While some of this
information is a bit dated the principles remain useful.
Click
here for
Sutherland, Susan E. 2001. Evidence-based Dentistry: Part I.
Getting Started. Journal of the Canadian Dental Association 67:204-6. This is a short introductory article that lists the skills needed for evidence based practice.
Click here
for
Sutherland, Susan E. 2001. Evidence-based Dentistry: Part II. Searching
for Answers to Clinical Questions: How to Use MEDLINE. Journal of the
Canadian Dental Association67:277-80. This article is a bit dated and quite general in covering the use of Medline (PubMed).
Click here
for
Sutherland, Susan E. & Stephanie Walker. 2001 Evidence-based Dentistry:
Part III. Searching for Answers to Clinical Questions: Finding E-vidence
on the Internet. Journal of the Canadian Dental Association67:320-3. Lists organizations and web sites that are more reliable than information found using search engines such as Yahoo and Google.
Click here
for Sutherland, Susan E. 2001. Evidence-based Dentistry: Part IV. Research
Design and Levels of Evidence. Journal of the Canadian Dental Association
67:375-8.
Click here
for
Sutherland, Susan E. 2001. Evidence-based Dentistry: Part V. Critical
Appraisal of he Dental Literature: Papers About Therapy. Journal of
the Canadian Dental Association67:442-5.
Click
here for Sutherland, Susan E. 2001. Evidence-based Dentistry: Part VI. Critical
Appraisal of the Dental Literature: Papers About Diagnosis, Etiology and
Prognosis. Journal of the Canadian Dental Association67:582-5.
Users'
Guides to Evidence-Based Practice The full text pre-publication
version of a series of articles on evidence based practice published in
JAMA. Covers Background, Primary Studies, and Integrative Studies. From
Centre for Health Evidence.
Appraisal Tools CASP Critical Appraisal Tools Covers how to appraise various sorts of studies including systematic reviews,
RCT's, cohort studies, & case control studies.
Critical
appraisal and using the literature This tool will teach you
how to appraise the value of research articles of various kinds using worked
examples. Follows the CASP method. From The University of Sheffield School
of Health and Related Research.
An Introduction
to Information Mastery This is an extensive course on
how to find and appraise the literature. From Department of Family Practice,
College of Human Medicine, Michigan State University.
Does learning critical appraisal
help? Maybe. Click
here to see the Cochrane systematic review
Hyde C, Julie Parkes, Jonathan Deeks, Ruairidh Milne 2000. Systematic
review of effectiveness of teaching critical appraisal.
Bias Is this a systematic review? If not, be aware that this is a probably single study
that may have design faults that can produce biased results.
If it is a systematic review, check to see that the literature
surveyed is complete and up to date. Cochrane Systematic Reviews should
be using only randomized controlled trial articles for the meta analysis.
If results other than RCT's are used, the author(s) should tell you this
and explain why other studies were included in the review.
Were patients randomly assigned to the treatment group
and was the assignment hidden from the patients and clinicians? If not stop reading,
or read this only if there are no randomized trials
on
the topic.
Were the prognostic indications similar for each group
(treatments and controls) at the start of the trial? If not was there some statistical
adjustment for this difference?
If not and there was no adjustment, stop
reading.
Was there sufficient follow up of the patients after
the treatment? Are all the patients who started the trial accounted
for at the end? Anything less than 80% follow
up should be considered of doubtful use. The length of follow
up required will be determined by the condition(s) studied. Does the article
have anything to say about compliance during the trial?
Were patients analysed in the groups to which they
were assigned? (Intention to treat)
Patients should be analysed in their original group whether
they have received the assigned treatment or not, otherwise
the initial randomization is jeopardized.
Were patients and clinicians blind to the treatments? Blinding removes psychological factors and 'extra treatment'
from the trial.
Did the groups receive equal treatment apart from the
intervention?
If the treating clinicians are able to determine which
patients receive the intervention (e.g. surgery), then different blinded
clinicians should be assessing the outcomes.
Statistics Is the best study type used for the investigation
This relates to the hierarchy of evidence. What is
the best study type to use for a drug intervention? If this type of study
isn't available what is the next best?
You might need to find information on Power Analysis to determine whether the authors had a sufficiently large sample size in their study. Use any internet search engine to find sites that discuss Power Analysis.
Authors of systematic reviews will often use statistics such as Odds Ratios, or Risk Ratios Odds Ratio and Relative Risk from Bandolier
7. Integrate
best evidence, and clinical judgment for
the benefit of individual patients
Do your patients
have the same condition(s) as those reported? Are they in the same age
group? Are there other environmental or biological differences?
Are the patients in the study so
different from yours that it would be unwise to use the study results?
Does the evidence give a clear indication
of whether an intervention is likely to help? This will influence what
you tell your patients. How much harm is the patient likely to suffer if
there is no intervention? If there is no clear indication, objective evidence
can still be presented to patients (and their families).
The judgment of whether to suggest
an intervention will sometimes come down to your experience and your knowledge
of the biology of the patient. Possible contraindications, and adverse
effects should be presented to the patient along with any benefits of the
intervention.
How to incorporate evidence in
your practice
BMJ article series Getting research
findings into practice
Click
here for Sheldon, T.A., G.H. Guyatt, &
A. Haines 1998. Getting research findings into practice: When to act on
the evidence. BMJ 1998; 317: 139-142 ( 11 July )
Click
here for Glanville, J., M. Haines, &
I. Auston 1998. Getting research findings into practice: Finding information
on clinical effectiveness. BMJ 1998; 317: 200-203 ( 18 July
)
Click
here for Haynes, B. & A. Haynes 1998.
Getting research findings into practice: Barriers and bridges to evidence
based clinical practice. BMJ 1998; 317: 273-276 ( 25 July
)
Click
here for Straus, S.E. & D.L. Sackett
1998. Getting research findings into practice: Using research findings
in clinical practice. BMJ 1998; 317: 339-342 ( 1 August )
Click
here for Lilford, R.J., S. G. Pauker, D.
A. Braunholtz, & J. Chard 1998. Getting research findings into practice:
Decision analysis and the implementation of research findings. BMJ
1998; 317: 405-409 (8 August)
Click
here for Bero, L.A., R. Grilli, J.M. Grimshaw,
E. Harvey, A.D. Oxman, M.A. Thomson 1998. Getting research findings into
practice: Closing the gap between research and practice: an overview of
systematic reviews of interventions to promote the implementation of research
findings. BMJ 1998; 317: 465-468 (15August)
Click
here for Garner, P., R. Kale, R. Dickson,
T. Dans, & R. Salinas 1998. Getting research findings into practice:
Implementing research findings in developing countries. BMJ 1998;
317:
531-535 (22 August)
Click
here for Buchan, Heather 2004. Gaps between
best evidence and practice: causes for concern. Medical journal of Australia180
(6 Suppl): S48-S49.
8. Present the
intervention options to the patient
How you present a range of decision options can influence what the patient decides. How you frame questions is known to be important.
Click here for access in the BSL to
Tversky, A., & D. Kahneman 1981 The framing of decisions and the psychology of choice. Science 211(4481) 453-458.
Click here for access in the BSL to
Godolphin, W. 2003 The role of risk communication in shared decision making. BMJ. 327(7417):692-3.
Clinicians should present the evidence
to patients in an objective way. If the intervention has potential to harm
the patient, then it is most important that the patient understands this.
The patient should be encouraged to suggest acceptable outcomes.
Shared decision making often results in better outcomes and increased patient satisfaction.
Click here for a PubMed Search designed by Mick Draper on
dentistry, and attitudes to health, and patient participation in decision making, and prognosis, outcome, or patient satisfaction
MedlinePlus
Patient information on more than 700 common conditions, a medical dictionary,
an encyclopaedia, and drug information. From US National Library
of Medicine and US National Institutes of Health
Oral Health Resources Site that includes consumer level information on Preventing cavities, gum disease, and mouth and throat cancer; Benefits of water fluoridation, guides for parents on brushing children's teeth. From (US) National Center for Chronic Disease Prevention and Health Promotion.
Record your questions, the relevant
articles you find, and whether you are modifying your treatments.
A patient centred approach assists treatment when combined with results from evidence based knowledge.
You should record your answerable questions and find that experience produces increasing the number
of successful searches as your questions become more relevant.
You should be getting to know the appropriate MeSH and recording these. You should be quicker
and better at critical appraisal. Your presentations to patients should
be more objective and related to their concerns.
This site was compiled by Mick
Draper The Barr Smith Library, The University of Adelaide, South Australia.
Go
to Part 2 of Evidence Based Dentistry, Using Cochrane Library
Go to Part
3 Evidence Based Dentistry, Using PubMed in Evidence Based Dentistry
The University of Adelaide Last Modified
16/05/2008
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