Evidence-Based Medicine
Since the 1980s, when McMaster Medical School in Canada termed the process of integrating scientific information into medical practice, Evidence-Based Medicine (EBM), it was formally adapted by the Evidence-Based Medicine Working Group, and a new paradigm for medical practice emerged. 1 Later, other health fields, like oral health care, began incorporating the same principle in their practice, and it became the most reliable way to practice dentistry. 2 Evidence-Based Dentistry (EBD) gives dentists the opportunity to perform dental treatment based not only on their daily experiences, but also on reliable scientific information, guaranteeing a greater predictability in the resolution of cases and longevity of the treatments offered to their patients. Nevertheless, it is important to emphasize, that clinical decisions should not be based only on scientific evidence. These decisions have to incorporate equal proportions of evidence, clinical expertise, and patient needs to achieve the “best clinical decision”. 3
The process of integrating scientific evidence into clinical practice is not easy. This is especially true for clinicians who are not familiar with the modern strategies available in searching for scientific information, as well as the search terms most frequently used for this purpose. Our aim is to outline an efficient strategy to help clinicians search and recognize the best scientific evidence that will be most applicable to their daily clinical practice.
How To Find The Best Evidence To Apply In Clinical Practice
EBD can be used to find the best scientific evidence to apply in daily dental practice and to reach the best decision for each clinical case. EBD consists of following a sequence of four proposed steps to search for evidence in every health field. 1 The use of this kind of guide makes it easier to search for the best and most appropriate answer to a clinical problem. It involves:
1. Converting information needs into answerable questions
2. Efficiently tracking down the best evidence to answer the question and critically appraising the evidence for its validity and usefulness
3. Integrating appraisal results with clinical expertise and patient values
4. Evaluating the outcomes
1. Defining the question of interest
The first step in making a more efficient search of information is to define what questions need to be answered. With the clinical challenges in mind, we determine the deficiencies and obstacles in solving the clinical case, and transform those obstacles into questions.
To formulate the questions of interest, the clinician must start defining the nature of the question. This falls into four main areas: 4,5
a) Therapy and prevention – to assess the effect of interventions on the patient
b) Harm or etiology – aiming to evaluate how exposure to risk factors influences patient outcomes
c) Diagnosis – to assess the performance of a test in patients presenting different conditions
d) Prognosis – to assess and estimate the future course of disease based on prognostic factors
In addition to the nature of the question, it is important to identify the main components of the question. The questions usually have four main components and to help identify
these components, several acronyms exist, like PICO or PECOT. 4 The acronym PICO arises from the following four components:
P: Patient population: What group of patients do you need information from (e.g. species, gender, age)?
I: Intervention: What is the procedure or treatment that you want to take (e.g. medical procedures, therapeutics, surgical techniques)?
C: Comparison: What do you want to compare (e.g. different treatments, medical versus surgical procedures)?
O: Outcomes: What is the effect of the intervention (e.g. return to normal function, reduction in severity of clinical signs, increased expected life span)?
Another acronym that can be used is PECOT that additionally includes the Exposure (not only interventions but the risk factor, intervention or prognostic factor), and Time. 6
Independent of the acronym used to formulate the questions, what is important is that the questions refine the information needed for the case efficiently and effectively. An example of a case using the PICO format is shown in (Fig. 1).
2. Finding the evidence and critically appraising the evidence
This is the most difficult part of the process for clinicians, because multiple databases exist in which current literature can be found, and many different types of studies can be found in these databases. To clarify and simplify this process the selection of databases and the type of study most appropriate to answer the question will be explained here in a few key steps.
The best sites to find appropriate information are those produced by academic centers (university and hospital sites), government-sponsored sites, professional organization sites and sites of medical search engines. 1 Each of these sites provides access to different levels of evidence, which differ in the degree of processing and summary.
The databases can also be divided according to the levels of evidence available, and are: 6
1. Those that provide access of all levels of evidence (comprehensive resources)
For example: The American Dental Association’s Center for Evidence-Based Dentistry(http://ebd.ada.org/en/evidence/),Trip(www.tripdatabase.com), SUMSearch(http://sumsearch.org), Epistemonikos(www.epistemonikos.org)
2. Those that provide access to summaries and guidelines
Such as: UptoDate(www.uptodate.com), (https://dynamed.ebscohost.com) and National Guideline Clearing house (www.guideline.gov).
3. Those that provide access only to pre-appraised research
This research includes systematic reviews and synopses, like in journal Evidence-Based Dentistry (www.nature.com/ebd/index.html), Journal of Evidence-Based Dental Practice (www.journals.elsevier.com/journal-of-evidence-based-dental-practice/), Dental Elf (www.thedentalelf.net) and Cochrane Oral Health Group (http://ohg.cochrane.org/reviews).
4. Those that provide access to non-pre-appraised research
They provide access to primary studies. These include information found in larger databases such as PubMed (www.ncbi.nlm.nih.gov/pubmed/), Embase (www.elsevier.com/online-tools/embase) and the Cochrane Central Register of Controlled Trials (www.cochrane.org/editorial-and-publishing-policy-resource/cochrane-central-register-controlled-trials-central). In large databases such as PubMed, it is possible to use filters such as Clinical Queries (www.ncbi.nlm.nih.gov/pubmed/clinical) to conduct more specific searches, and to take advantage of tools such as “Related Citations” to find additional relevant material. 7
In selecting the best site to consult, dentists should keep in mind that the resource should be based on the current best evidence. It should be both comprehensive yet specific enough to cover the question of interest, and it should be up to date and available to the practitioner who wants to use it. 6
Regardless of the level of processing and summary involved, all levels of evidence should be used with caution; some data is truly informative, while other data is skewed through bias to support a point. For instance, the claim from a Colgate study indicating, “More than 80% of dentists recommend Colgate” led consumers to believe that Colgate was recommended over and above other brands. This was based on deceptive statics, where the dentists in the study were allowed to recommend more than one brand, including both Colgate and its competitor. In this way, the company allowed the consumer to assume that 4/5 dentists would choose Colgate over its competitors. (Yoo Jung Kim et al 2016).
The clinician should be able to differentiate evidence that inspires confidence from evidence that does not. Notably, evidence resources can be applied to a hierarchic “pyramid of evidence” to rank the evidence from strongest to weakest 1 (Fig. 2).
Determining the nature of the question by using the acronyms discussed like PICO or PECOT helps with evaluation of the types of studies. For questions regarding therapy or prevention—well designed and conducted randomized controlled trials should be preferred over observational studies, which are superior to unsystematic clinical observations or case reports. 4 For questions of harm, etiology and prognosis— generally the most appropriate designs are observational studies, with the lowest risk of bias4 in which the researcher compares outcomes between groups exposed and unexposed to the risk or prognostic factor of interest. The preferred study designs for questions regarding diagnostic test properties are cross-sectional studies, in which the properties of the diagnostic test are compared against those of a reference standard. 4
Within each level of evidence, clinicians must evaluate resources as stronger or weaker after a thorough appraisal based on clinical epidemiology: study design, bias and statistical interference. These parameters will permit a critical appraisal of the evidence. 3,6
After choosing the most appropriate study design to answer clinical questions, it is important to evaluate the literature selected according to the question proposed. There is another acronym to help at this stage – RAAM. 3 It can help to identify the studies that are more representative of clinical doubt.
R: Is the study population representative of your patient?
A: In intervention studies, what was the allocation of the animals in the experimental design? Was it randomized or was it stratified?
A: Were all the animals accounted for at the end of the study?
M: Were the measurements of outcomes evaluated objectively? Were evaluators blinded?
If the study/studies selected after the search were judged appropriate to answer the specific clinical doubt, it is possible to pass to the next step in the four-step guide, where this information is integrated by the clinician to the patient’s condition.
3. Integrating the evidence
The scientific evidence will lead to the best option in solving the clinical problem. However, some questions must be answered before trying to apply evidence-based-data into your daily clinical practice. These questions are related to the patient’s biological, cultural and financial situation: Is the patient in agreement with the treatment proposed? Can he or she afford the recommended procedures? Are the options within the cultural, ethical and religious limits? There are also questions of clinical abilities and infrastructure: Does the clinician have the skills and knowledge needed to perform the procedures suggested by the scientific evidence? Does the clinic have the equipment necessary for it? If the clinician and the clinical structure are not ready to implement the best choice of treatment found in the literature, is the patient is willing to seek a referral center that provides this type of treatment, such as a university, hospital or a specialist?
After answering these questions it is time to integrate the best evidence, your clinical expertise, with the patient’s needs and client’s preferences, to decide the best plan of treatment for case resolution.
4. Evaluating outcomes
With the health care industry experiencing an explosion of research which promises to shift the paradigm towards the detection, diagnosis, and management of oral diseases, the outcomes need to be evaluated once the EBD process is applied: Did you find the expected results? If not, how did the results differ? The failures or success with respect to the diagnostics, treatment plan, or prognosis can be documented and used as evidence in the ‘‘clinical expertise’’ portion of EBD. These experiences may also be published as case reports, case series or observational studies, contributing to the evidentiary portion of EBD.
Evaluation of your individual EBD outcome or performance is equally important to the evaluation of clinical decision outcomes. This process should include self-evaluation procedures for every step of the EBD process. Did the clinical question yield the appropriate results? Were too many or too few resources located? Was the critical appraisal process cumbersome? Were the articles internally and externally valid? How did you integrate the client’s preferences, patient’s needs, and your clinical expertise with the evidence? Were the outcomes of your clinical decision what you expected? Critical self-assessment of the EBD process allows practitioners to sharpen their EBD skills and identify areas for improvement. An example of a clinician using EBD approach is given for a couple of cases in (Fig. 3).
Summary
Moving forward, we would strongly recommend that practitioners carefully review the scientific data available on the internet because EBD is not easy for beginners; however, it is necessary when looking to provide the best treatment outcomes for our patients. To integrate EBD in your clinical practice you may begin by identifying one pertinent clinical question every day and going through the four steps. In addition, over time your clinical knowledge will increase with EBD, allowing the dental practice to explore new areas of specialty or cutting-edge advances in the dental field. OH
1. School of Dentistry and Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada.
2. Department of Pediatric Dentistry, Bauru Dental School, University of Sao Paulo Bauru, Sao Paulo, Brazil.
Supported: Canadian Institutes of Health Research (CIHR grant #106657). WLS is recipient of a CIHR New Investigator Award (grant #113166).
Oral Health welcomes this original article.
References
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6. Brignardello-Petersen, R., et al., A practical approach to evidence-based dentistry: How to search for evidence to inform clinical decisions. J Am Dent Assoc, 2014. 145(12): p. 1262-7.
7. Agoritsas, T., et al., Sensitivity and predictive value of 15 PubMed search strategies to answer clinical questions rated against full systematic reviews. J Med Internet Res, 2012. 14(3): p. e85.
