Evidence-based practice for researchers concentrates on the types, quality, and conduct of research studies that gather evidence that may be informative for clinical practice or clinical decision making. It also involves the process of gathering and synthesizing scientific evidence from various sources and translating it to be applied to clinical practice.
Study Designs that Gather Evidence
The design of a study has great impact on the trustworthiness of its results and hence, the level of scientific evidence it can provide. Various entities have come up with a hierarchical system for grading levels of scientific evidence based on the strengths and weaknesses of various study designs. In general, the highest level of evidence that can inform clinical practice comes from randomized controlled trials and systematic reviews or meta-analyses of randomized controlled trials. However, in some cases other study designs (cohort, case-control, cross-sectional, case studies, etc.) can also provide information useful for clinical decision-making. Below is a list of common study designs and the situations in which they may best be used to inform clinical practice.
Summary of Different Study Designs
|
Study Design
|
Description
|
Answers Questions About
|
| Meta-analysis
|
A special case of a systematic review in which data is statistically combined from multiple studies to calculate a summary measure of effect.
|
Treatment Prevention Harm
|
| Systematic Reviews
|
A systematic, objective, transparent approach to summarizing the scientific literature on a single topic.
|
Treatment Prevention Harm
|
| Randomized Controlled Trial
|
A group of subjects are randomly assigned to treatment/intervention and control group and outcomes are measured prospectively.
|
Treatment Prevention Harm
|
| Cohort
|
A group of subjects, usually without disease/outcome at baseline, are observed over time for the development or progression of disease. Exposures or risk factors are hypothesized or known and assessed prior to development of disease.
|
Incidence Risk or Preventive Factors Prognosis
|
| Case-control
|
Patients are grouped based on disease/no disease status and risk factors for disease are retrospectively recalled or collected from medical records.
|
Risk or Preventive Factors
|
| Cross-sectional
|
Risk factor and disease status are collected at a single point in time.
|
Prevalence
|
| Case Report / Case Series
|
Detailed report of a single patient or groups of patients.
|
Unique or rare conditions New treatment regimes
|
Databases
Finding and Interpreting Systematic Reviews and Meta-Analyses
Finding, interpreting, and applying information from individual randomized controlled trials or systematic reviews and meta-analyses to your clinical practice is a crucial part of evidence-based practice. Researchers also need ready access to the most up-to-date research in clinical practice to assess gaps and areas with high need for further investigation.
General Evidence-Based Practice Databases
The Cochrane Collaboration is considered one of the definitive sources for systematic reviews and meta-analyses informing healthcare decision-making. Multiple resources are available including the Cochrane Library, a database of systematic reviews, resources, and training on how to do systematic reviews, free software for data analysis, and reporting guidelines.
Cochrane databases (available at
Cochrane Library):
Other general evidence-based practice databases:
Rheumatology Relevant Databases
Primary Care/Internal Medicine/Rheumatology
- BMJ Evidence-Based Medicine – systematically searches a wide range of international medical journals applying strict criteria for the validity of research. Articles are summarized and commentary on their clinical applicability is added.
- BMJ Clinical Evidence – reliable and relevant reviews of healthcare interventions.
- Essential Evidence Plus – clinical questions and reviews geared toward family practice in the form of Info Poems (Patient Oriented Evidence that Matters).
Physical Therapy
- Physiotherapy Evidence Database (PEDro) - details and abstracts of randomized controlled trials, systematic reviews and evidence-based clinical practice guidelines in physiotherapy which are rated based on quality.
Occupational Therapy
- OT Search – subscription service managed by the American Occupational Therapy Association to a bibliographic database covering the literature of occupational therapy and its related subject areas.
- OT Seeker – database containing abstracts of systematic reviews, randomised controlled trials and other resources relevant to occupational therapy interventions.
- Occupational Therapy Critically Appraised Topics (OT CATs) – critically appraised topics on occupational therapy from the University of Western Sydney.
Nursing
Guides for Interpreting Systematic Reviews and Meta-Analyses
Navigating the scientific literature can be a daunting task for busy clinicians and researchers. Systematic reviews and meta-analyses may provide a condensed synthesis on a given topic, but as with any scientific study, have inherent strengths and weaknesses. Several published guides are available to help readers digest and apply the information gleaned from these types of Evidence-Based Practice studies.
Evaluation Tools
The type of study design and how a study is executed, data analyzed and reported all play an integral role in the overall study quality and its ability to inform scientific evidence. A variety of different study quality rating tools and systems to rate the level of evidence exist. A sample of tools and level of evidence scales are below.
Tools to Rate Study Quality
Standardized Reporting Guidelines
Reporting guidelines are helpful resources for both the planning and publication of research studies. First developed to assist authors with the critical pieces of information to include in published manuscripts, are now also important for doing systematic reviews and meta-analyses and during the planning phase of many clinical and observational studies.
Systematic Reviews / Meta-Analysis Reporting Guides
- MOOSE – Meta-analysis of Observational Studies in Epidemiology: A Proposal for Reporting
- QUORUM – Improving the Quality of Meta-Analyses of Randomized Controlled Trials: Quality of Reporting Meta-analyses
Controlled Trials and Observational Study Reporting Guides
- CONSORT – Consolidated Standards of Reporting Trials
- STROBE – Strengthening the Reporting of Observational Studies in Epidemiology
- TREND - Transparent Reporting of Evaluations with Non Randomized Designs
- STARD - Standards for Reporting of Diagnostic Accuracy