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?