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How to evaluate a clinical study and research resources

Jan. 14, 2015
There's a method to evaluating research and clinical studies, which are designed to help practitioners during their practice of oral care. Maria Perno Goldie, RDH, MS, offers some tips for making the most of the current research.

Dental hygienists and dental clinicians administer treatment or preventive maintenance. Clinicians use and recommend products and procedures. In order to make decisions based on evidence, it is crucial that practitioners are able to understand and assess clinical studies. This article will discuss the steps in evaluating a clinical study, delineate between evidence-based practice and research, and provide other resources for evidence-based decision making.

Clinicians must read research articles in order to gain new knowledge, and they must also evaluate what they read. In order to critically evaluate an article, clinicians should follow an orderly process to determine the strengths and weaknesses of the study and subsequent article. This will help assess the validity of the research conclusions and their usefulness in clinical practice. The suitability of the research question and design, and the materials and methods used by the investigators, should be evaluated. The statistics used must also be appropriate to the study design. In order to be useful, the study results should be directly applicable to patients.

There are 10 questions that can guide the process of evaluating a research study. They are – Is the study question relevant? Does the study add anything new? What type of research question is being asked? Was the study design appropriate for the research question? Did the study methods address the most important potential sources of bias? Was the study performed according to the original protocol? Does the study test a stated hypothesis? Were the statistical analyses performed correctly? Do the data justify the conclusions? Are there any conflicts of interest?(1)

Clinical research questions are most often about the effectiveness of a treatment, the cost effectiveness, the safety, the incidence or prevalence of a disease, risk factors, prognosis, and other predictions of clinical outcomes. A PICO question can be posed, as many clinical or research questions can be divided into four components.

ntervention/indicator (treatments and therapies, use of a specific diagnostic test, treatment, adjunctive therapy, medication or the recommendation to the patient to use a product or procedure.)
omparator/control (the alternative you are considering)
utcome (alternative you are considering, and it should be specific and limited to one alternative choice in order to facilitate an effective computerized search.

Questions could be in regard to therapy or prevention, diagnosis, etiology, or prognosis. A PICO Worksheet and Search Strategy page and other useful information to assist in your search are available for download.(2,3) There is also a link to many other PICO resources.(4) For more on Evidence-Based Decision Making, visit the website in the fifth reference.(5)

After the question is formulated, search for the evidence. There are many ideas in the references to help with a search. Perform a critical appraisal of the results, and then decide what action to take from the findings. Finally, evaluate the new or modified practice you wish to implement or recommend to patients.

There are different types of studies located at different levels of the hierarchy of evidence. The closer to the top of the pyramid, usually the better the evidence. All types of studies, from laboratory studies to evidence-based guidelines, are important, but most of our treatment should be based on randomized controlled trials and above in the hierarchy of evidence.

Another good research resource is the National Center for Dental Hygiene Research & Practice (NCDHRP) Dental Hygiene Research Toolkit by Denise Bowen, RDH, MS, editor.(6) It contains an overview of the research process, research ethics and protocol requirements, review of the literature, research design and methods, scientific writing and dissemination of research findings, the DHNet, and registering your study with the National Institutes of Health (NIH). There is also an Educator's Guide for Teaching Research, Best Practices for Incorporating Dental Hygiene Research & Evidence Based Decision Making (EBDM) Into Dental Hygiene Curriculum.(7) The American Dental Hygienists’ Association (ADHA) has a Research Center and a National Dental Hygiene Research Agenda.(8,9)

(6) (7)

We have discussed evidence quite a bit in this article and in the last few years. As we know, evidence-based medicine (EBM) and evidence-based dentistry (EBD) seek to apply the best available evidence gained from the scientific method to clinical decision making. It strives to assess the strength of evidence of the risks and benefits of treatments, including no treatment, and diagnostic tests. But what is the difference between EBM or EBD and research? There are three important differences between research and evidence-based practice.(10) While both are systematic, each serves a different purpose. Research is used to conduct an investigation, the results of which will add to existing evidence. Evidence-based practice attempts to search for and appraise best evidence, some of which will be provided by research.

Another important difference between research and evidence-based practice relates to the different endpoints of each. Research concludes with the outcome specified at the beginning of the study, which could contain a statement of relationships between variables, a description or exploration of current practice, or the results of the testing of a specific hypothesis or theory. These would then be used to provide recommendations for additional research or recommendations for changes in practice. Evidence-based practice ends by making clinical decisions, which might involve changing practice based on the new evidence. An example of this process is seen in the formation of the new guidelines on premedication, which is the first article of this e-newsletter.

The third important difference is how the existing evidence is used. Research is less concerned with existing evidence, relying instead on other research evidence in order to build up adequate validation to conduct the investigation. In comparison, evidence-based practice relies on a variety of evidence, including that arising from patients’ individual needs.

The bottom line is that EBM and EBD have their origins in practice, and draw on research, along with other evidence, to bring about changes in practice.

Maria Perno Goldie, RDH, MS, is the editorial director of RDH eVillage FOCUS.

1. Young JM, Solomon MJ. How to Critically Appraise an Article. Nat Clin Pract Gastroenterol Hepatol. 2009;6 (2):82­91.
2. https://www.libraries.psu.edu/content/dam/psul/up/tutorials/ebpt/PICOWorksheetSearchStrategy.pdf.
3. http://guides.lib.purdue.edu/content.php?pid=296535&sid=2435417.
4. http://www.usc.edu/hsc/ebnet/ebframe/basicslinks.htm#P.
5. http://www.usc.edu/hsc/ebnet/.
6. https://dent-web10.usc.edu/dhnet/research_kit.pdf.
7. https://dent-web10.usc.edu/dhnet/educator_guide.pdf.
8. http://www.adha.org/research-center.
9. https://www.adha.org/resources-docs/7111_National_Dental_Hygiene_Research_Agenda.pdf.
10. Carnwell R. Essential differences between research and evidence-based practice. Nurse Researcher, Volume 8, Number 2, p. 55-68.