Evidence-Based Practice in Healthcare

Research Methods

• Research methods are discussed in module 13.
• A quiz review is presented in module 13.
• Quiz questions include: Which hypothesis (research vs. null) is involved in Type 1 and Type 2 Errors? What is probability? What is a p value?

Systematic Reviews & Meta-analyses

• A systematic review is a review and summary of studies based on a focused clinical question.
• If statistical methods are used to synthesize the studies, the review is known as a meta-analysis.
• A meta-analysis combines the statistical data from all included studies to arrive at a more precise estimate of the effect or outcome.
• Types of systematic reviews include Meta analysis, Integrative, Rapid, Scoping, Narrative, Scoping, and Realist.

Systematic Review: Process

• A systematic review starts with a clearly focused question called a PICO(T) question.
• PICO(T) includes: Population, Intervention, Comparison, Outcome, and Time.
• The researcher locates published and unpublished studies consistent with the PICO(T) question.
• Appraising the strength and quality of the evidence in each individual study is a key part.
• Synthesizing the overall strengths and weaknesses of the studies in aggregate is another key part.
• The researcher identifies studies based on inclusion and exclusion criteria (e.g., disease process, setting, population, geographic location, research method, statistical significance, sample size).
• Researchers develop an explicit, reproducible methodology to search for, identify, and collect the included studies.
• Using critical appraisal tools to assess the strength and quality of the evidence in each study, and overall is necessary.
• General appraisal questions from earlier modules (e.g., modules 4, 10, 12) are applicable to quantitative or qualitative studies.
• Determining the strength and quality of the evidence for practice based on internal and external validity; sampling, variable measurements, and data analysis are all factors that play a role.
• Methods are reviewed for applicability of findings to practice, considering the PICOT question.

Evaluation of Research Results: Terminology Used in Meta-Analysis

• Terminology used in meta-analysis includes confidence interval, likelihood ratio, predictive value, number needed to treat (NNT), odds ratio, relative risk, sensitivity, and specificity.

Relative Risk

• Relative Risk (RR) is the probability of an outcome in an exposed group versus an unexposed group.
• RR = 1 indicates no difference between groups.
• RR < 1 indicates a reduced probability.
• RR > 1 indicates an increased probability.
• Examples include evaluating the risk of developing lung cancer in smokers versus nonsmokers, or thyroid cancer in a nuclear-radiation-exposed group versus a control group.
• RR is calculated based on a table, such as the (A, B, C, D) table

Relative Risk Reduction

• Relative Risk Reduction (RRR) estimates the percentage of baseline risk removed by a therapy/intervention.
• Calculated as absolute risk reduction (ARR).
• ARR = (EER – CER) / CER; where EER is experimental group event rate and CER is Control group event rate

Odds Ratio

• Odds Ratio (OR) estimates the odds of an event occurring in a treatment group relative to the odds in a control group.
• OR = 1 indicates no difference between groups.
• OR < 1 indicates increased odds in the control group.
• OR > 1 indicates increased odds in the treatment group.
• OR = (a/b)/(c/d) = ad/bc. (a/b= odds of treatment group; c/d= odds of control group)
• Used frequently in case-control studies.

Sensitivity & Specificity

• Sensitivity is the ability of a test to detect true positives (few false negatives).
• Specificity is the ability of a test to detect true negatives (few false positives).
• Sensitivity and specificity have an inverse relationship.
• Predictive value of a test is determined by sensitivity and specificity of the test and the prevalence of the disease in the tested population.
• Values are calculated using a formula (e.g. True positives/ (true positives + false negatives) and True negatives/ (true negatives + false positives).

Predictive Value

• Predictive value is how clinicians use sensitivity and specificity.
• Positive predictive value (PPV) is the likelihood a patient has a disease given a positive test result.
• Negative predictive value (NPV) is the likelihood a patient does not have a disease given a negative test result.
• These values depend on the population being tested and the prevalence of the disease.

Likelihood Ratio

• Likelihood ratio (LR) is a measure of how much a given test result is expected in patients with a specified disorder versus patients without the disorder.
• It measures the power of a test to change the pre-test probability into the post-test probability of a disease being present for a patient.
• Large LR values indicate strong evidence for a diagnosis.
• LR can be positive or negative.

Number Needed to Treat (NNT)

• NNT is a measure of the effectiveness of an intervention.
• It represents the number of people who need to receive a treatment/intervention for one patient to experience a benefit.
• Lower NNT values are associated with cost-effective interventions.
• High NNT values are associated with higher costs and relatively lower efficacy.

Confidence Intervals (CI)

• CI is a range of values based on a sample of a population.
• The likelihood that the population parameter will fall within a certain range on repeat testing.
• CI of 95% is most common, which means in a normal distribution of values, it contains all values within two standard deviations of the population mean.

Types of Systematic Reviews

• Types categorized by the methods they employ–including meta-analysis, integrative reviews, rapid reviews, scoping reviews, narrative reviews, and realist reviews.

Meta-Analysis

• Statistical techniques to assess and combine studies of the same design to get a precise estimate of effect.
• Provides Level I evidence.
• Determines the impact of a number of studies.

Effect Size

• Calculated using the difference in average scores between two groups in studies.

Forest Plot

• Visually depicts the results of analyzing multiple studies.
• Shows the results in an easy-to-understand graphical format.

Integrative Review

• Critical review of an area without statistical analysis or hypothesis synthesis.
• Broadest category of review.
• May include theoretical/methodological studies or results of different research studies (quantitative or qualitative).
• Statistics are not used for summarizing or drawing conclusions.
• Although systematic reviews are useful, they must also be reviewed for potential bias and critiqued for scientific rigor.

Cochrane Collaboration

• Largest repository that prepares and maintains health care interventions and reviews.

Systematic Review Tools

• Tools like PRISMA and MOOSE are used in the process.

Clinical Practice Guidelines

• Guidelines that serve as practice standards.
• Link research to practice.
• May be evidence based (a scientific process) or expert based (using the opinion of experts).

Critical Appraisal

• Method for evaluating the quality/strength of guidelines, evidence, studies, etc that are being used in the practice.
• Questions include, but are not limited to those about the PICO question applicability, the review’s comprehensiveness, the dates of inclusion, criteria for assessment, whether studies were conducted individually or collectively, the method of study combination, and whether the clinical conclusions are relevant and supported.

Developing EBP: Clinical Inquiry

• Strategy 1: Asking a focused clinical question that outlines the population, intervention, comparison, and outcome.
• Question categories including prognosis, harm, therapy, and diagnosis categories.

Developing EBP: Literature Search

• Factors influencing a literature search (information literacy, librarian consultation, electronic indexes/databases, tutorials to search databases).
• Screening results (peer-reviewed journals, similar settings/samples, study sponsorship).

Developing EBP: Critical Appraisal

• Criteria for appraising therapy, diagnosis, prognosis, and harm articles.

The Iowa Model

• The Iowa Model framework includes methods and structures that guide a process that ensures EBP strategies are employed in practice
• Includes the stages of a clinical question, development of a team, evidence collection/synthesis, and dissemination/implementation of the resultant findings.
• Includes strategies for addressing the EBP topic and for managing the different areas of the process, including user adoption, social systems, implementation strategies, and evaluation of the results.

Using the lowa Model

• Methods for reading and critiquing articles, for deciding which studies to use, defining summary tables, identifying critical evaluation points for research designs and findings; and identifying strategies for promoting EBP implementation.

Evidence-Based Practice & the AGCNS

• Challenges and expectations for meeting EBP expectations (e.g., building capacity, education of clinicians, engaging patients), and the emerging body of knowledge in translation science.

Test your knowledge on evidence-based practice (EBP) and related concepts in healthcare research. This quiz covers key elements such as systematic reviews, meta-analysis, and clinical practice guidelines. Challenge yourself to understand the measures and frameworks utilized in EBP.