Evidence-Based Practice Notes

Minimizing Bias

• Bias can be minimized or overcome by using Bayes’ Theorem.
  • Bayes’ Theorem involves updating prior beliefs based on new information.
    1. Start with a prior belief (A).
    2. Obtain new information (B).
    3. Update the belief accordingly (A given B).

Statistics/Research Usage

• Statistics and research can be used to:
  • Describe the world.
  • Assess causal effects between variables.
  • Predict outcomes.

Evidence-Based Practice (EBP)

• EBP is the integration of best research evidence with clinical expertise and patient values.
• It also encompasses the conscientious, explicit, and judicious use of current best evidence in making decisions about patient care (Sackett, 1996).
• EBP combines:
  • Research evidence
  • Clinical expertise
  • Patient values

Traditional vs. Evidence-Based Decision Making

• Traditional decision-making relies on:
  • Experience and judgment.
  • Clinical circumstances.
  • Patient preferences.
• Evidence-based decision-making incorporates:
  • Experience and judgment.
  • Clinical circumstances.
  • Patient preferences.
  • Scientific evidence.

The Necessity of EBP

• EBP is crucial because of:
  • The overwhelming volume of information.
    • Described as "drinking from a fire hydrant."
  • Waste in health research.
    • Chalmers & Glasziou (2009) indicate that 50% of health research resources are wasted at each step, resulting in 85% overall waste.
  • Mistakes arising from flawed theories.
    • Hormone replacement therapy, which theoretically reduced cardiovascular risk, increased the incidence of breast cancer in women.

Clinical Decision Example (Hypertension Treatment)

• Clinical decisions in hypertension treatment are based on:
  • Level of blood pressure.
  • Patient’s age.
  • Physician’s year of graduation from medical school.
  • Amount of target-organ damage.

Continued Skills

• It's important to keep clinical skills up to date.

Causes of Research Waste

• Low-priority questions are addressed.
• Important outcomes are not assessed.
• Clinicians and patients are not involved in setting research agendas.
• Over 50% of studies are designed without reference to systematic reviews of existing evidence.
• Over 50% of studies fail to take adequate steps to reduce biases (e.g., unconcealed treatment allocation).
• Over 50% of studies are never published in full.
• There is biased under-reporting of studies with disappointing results.
• Over 30% of trial interventions are not sufficiently described.
• Over 50% of planned study outcomes are not reported.
• Most new research is not interpreted in the context of systematic assessment of other relevant evidence.

Additional Reasons for EBP

• Knowledge evolves rapidly, demanding efficient methods to stay current.
• Resources (time and money) are limited.
• Variations exist in practice patterns, with reliance on authority over empirical evidence.
• A gap persists between current knowledge and its application to care.

Bridging the Gap

• EBP aims to bridge the gap between what we know and what we do.

Practitioner Status

• A study of 321 PTs in England & Australia found that:
  • Over 90% of treatment choices reflected initial training.
  • Research literature was the least important factor in choosing techniques; review articles fared only slightly better (Turner & Whitfield, 1997).

Barriers to EBP

• APTA survey identified top barriers:
  • Lack of time to read research.
  • Lack of available research for specific patient populations.
  • Lack of easy access to research.
  • Lack of time to learn how to apply EBP.
• Jette et al. (2003) found that:
  • Most PTs consider EBP important.
  • 34% had low confidence in search abilities.
  • 44% had low confidence in interpretation abilities.
  • Older PTs are less likely to have training, less familiar with systems, and have less confidence overall.

Barriers to EBP for Stroke

• Common barriers:
  • Insufficient time.
  • Lack of generalizability of research findings.
  • Lack of research skills.
  • Lack of understanding of statistics.
  • Inapplicability of research to unique patients.
  • Inability to critically appraise.
  • Isolation from peers.
  • Lack of information resources.
  • Lack of an organizational mandate.

Definition of Evidence

• "Not everything that can be counted counts, and not everything that counts can be counted." - Albert Einstein
• Emphasis on the best available external clinical evidence.

Practitioner Needs

• Practitioners need:
  • Theory: Justifications for treatment based on basic or applied work answering why something should work.
  • Evidence: Justifications for treatment based on applied work (on patients) answering if something works.

Example: Spinal Stability

• Less Useful:
  • Devoid of muscle, the spine is unstable.
  • Strengthening key muscles can lead to a stable spine.
  • A more stable spine should decrease the risk of recurrence of LBP.
• More Useful:
  • A randomized clinical trial demonstrates that pain and function improve initially and at 1- and 3-year follow-up in patients with LBP undergoing specific stabilization exercises (O'Sullivan et al., 1997).

APTA Strategic Plan

• Goal: Transform the profession.
• Best practices in education will lead to physical therapist practice marked by value and associated with the use of evidence, best practice principles, and outcomes research.
• Strategies include:
  • Addressing unwarranted variations in clinical practice.
  • Integrating the movement system.
  • Engaging with the Education Leadership Partnership.
  • Providing professional development opportunities for faculty.
  • Advancing diversity and inclusion.
  • Promoting PT participation in primary care delivery models.
  • Assessing current strategies for advancing PT health services and outcomes research.

Fundamental Principles of Evidence

• Considerations:
  • Benefits and risk
  • Inconvenience
  • Costs
  • Patient values
• The evidence is never enough; a hierarchy of evidence exists.

Hierarchy of Evidence

• Address two questions:
  • Where does an individual article fall on the hierarchy?
  • Where does the preponderance of literature place the question?

Levels of Evidence (Individual Studies)

• 1a: Systematic Review of RCTs
• 1b: Individual RCT
• 2a: Systematic Review of Cohort Studies
• 2b: Individual Cohort Study
• 2c: Outcomes Study
• 3a: Systematic Review of Case-Control Studies
• 3b: Individual Case-Control
• 4: Case Series
• 5: Expert Opinion

Types of Studies in Hierarchy

• Case Study
• Systematic Review
• Meta-Analysis
• Case Control
• Clinical Practice Guideline
• Randomized Controlled Trial (RCT)
• Cohort Study

Randomized Controlled Trial (RCT)

• Definition: A study in which participants are randomly allocated to different clinical interventions.

RCT Advantages

• Good randomization washes out population bias.
• Easier to blind/mask compared to observational studies.
• Results can be analyzed with well-known statistical tools.
• Populations of participating individuals are clearly identified.

RCT Disadvantages

• Expensive in terms of time and money.
• Volunteer biases may lead to a non-representative population.
• Does not reveal causation.
• Loss to follow-up can be attributed to treatment.

Example: Beta-Alanine Study

• Study: No Effect of β-alanine on Muscle Function and Kayak Performance (Bech et al., 2018).
• Purpose: To investigate if β-alanine supplementation counteracts muscular fatigue or improves athletic performance.
• Methods: Elite kayak rowers supplemented with β-alanine or placebo for 8 weeks.
• Results: No detectable effect of β-alanine supplementation on kayak ergometer performance.
• Conclusions: Two-minute MVC characteristics are unaffected by β-alanine supplementation in elite kayakers.

Cohort study

• A study design where one or more samples (called cohorts) are followed prospectively and subsequent status evaluations with respect to a disease or outcome are conducted to determine which initial participants exposure characteristics (risk factors) are associated with it

Cohort study Advantages

• Subjects in cohorts can be matched, which limits the influence of confounding variables
• Standardization of criteria/outcome is possible
• Easier and cheaper than a randomized controlled trial (RCT)

Cohort study Disadvantages

• Cohorts can be difficult to identify due to confounding variables
• No randomization, which means that imbalances in patient characteristics could exist
• Blinding/masking is difficult
• Outcome of interest could take time to occur

Case-Control Study

• Definition: A study that compares patients who have a disease or outcome of interest (cases) with patients who do not have the disease or outcome (controls).
  • Looks back retrospectively to compare how frequently the exposure to a risk factor is present in each group to determine the relationship between the risk factor and the disease.

Case-Control Study Advantages

• Good for studying rare conditions or diseases
• Less time needed to conduct the study because the condition or disease has already occurred
• Lets you simultaneously look at multiple risk factors
• Useful as initial studies to establish an association
• Can answer questions that could not be answered through other study designs

Case-Control Study Disadvantages

• Retrospective studies have more problems with data quality because they rely on memory
  • People with a condition will be more motivated to recall risk factors (also called recall bias).
• Not good for evaluating diagnostic tests because it’s already clear that the cases have the condition and the controls do not
• It can be difficult to find a suitable control group

Case Report

• Definition: An article that describes and interprets an individual case, often written in the form of a detailed story

Case Report Information

• Unique cases that cannot be explained by known diseases or syndromes
• Cases that show an important variation of a disease or condition
• Cases that show unexpected events that may yield new or useful information
• Cases in which one patient has two or more unexpected diseases or disorders
• Case reports are considered the lowest level of evidence, but they are also the first line of evidence, because they are where new issues and ideas emerge

Systematic Review

• Definition: A document often written by a panel that provides a comprehensive review of all relevant studies on a particular clinical or health-related topic/question

Systematic Review advantages

• Exhaustive review of the current literature and other sources (unpublished studies, ongoing research)
• Less costly to review prior studies than to create a new study
• Less time required than conducting a new study
• Results can be generalized and extrapolated into the general population more broadly than individual studies
• More reliable and accurate than individual studies
• Considered an evidence-based resource

Systematic Review disadvantages

• Very time-consuming
• May not be easy to combine studies

Meta-Analysis

• Definition: A subset of systematic reviews; a method for systematically combining pertinent qualitative and quantitative study data from several selected studies to develop a single conclusion that has greater statistical power
  • Used to establish statistical significance with studies that have conflicting results
  • Develop more correct estimate of effect magnitude

Meta-Analysis Advantage

• Greater statistical power
• Confirmatory data analysis
• Greater ability to extrapolate to general population affected
• Considered an evidence-based resource

Meta-Analysis Disadvantage

• Difficult and time consuming to identify appropriate studies
• Not all studies provide adequate data for inclusion and analysis
• Requires advanced statistical techniques
• Heterogeneity of study populations

Practice Guidelines

• Definition: A statement produced by a panel of experts that outlines current best practice to inform health care professionals and patients in making clinical decisions

Practice Guidelines Advantages

• Created by panels of experts
• Based on professional published literature
• Practical guidance for clinicians
• Considered an evidence-based resource

Practice Guidelines Disadvantages

• Slow to change or be updated
• Not always available, especially for controversial topics
• Expensive and time-consuming to produce
• Recommendations might be affected by the type of organization creating the guideline

GRADE

• Lower quality if: Study limitations, Inconsistency, Indirectness, Imprecision, Publication bias
• Higher quality if: Large effect, Dose response

Steps in EBP

• Identify the need for information and develop a question
• Conduct a search for the best possible evidence
• Critically appraise the evidence
• Integrate the evidence with clinical expertise and patient values
• Evaluate the effectiveness and efficacy of your efforts

EBP methodology

• Precisely defining a question related to a patient problem or question
• Accessing and synthesizing evidence useful in answering the questions
• Applying the knowledge to patient care

The Evidence Cycle

1. Ask
2. Acquire
3. Appraise
4. Apply
5. Assess

Background vs Foreground

• Background
  • General knowledge about disease or intervention
  • Foundational knowledge about clinical condition
  • Reflect a desire to understand the nature of an individual’s desire or need
• Foreground
  • Help you obtain specific knowledge
  • Assist in developing diagnosis, prognosis, or plan of care for a specific patient

Example: ACL

• Background:
  • What is the typical mechanism of injury for an ACL?
• Foreground
  • For individuals 35-50 who are post-surgical ACL repair does the use of a CPM machine improve their return to sporting activities?

Defining the Question: PICO

1. Patient (or Problem)
   • How would I describe a group of patients similar to mine?
2. Intervention (or cause, prognosis)
   • Which main intervention am I considering? Be specific.
3. Comparison (or control)
   • What is the main alternative? Be specific.
4. Outcome(s)
   • What do I hope to accomplish?

How Much Do You Need To Read?

• Clinicians need only about 20 articles per year and 5 to 50 articles in a specialty
• Need to consume 1-2% of published evidence
• How do we identify what we need to know?