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How we work

What is evidence-based medicine?

Evidence-based medicine is the use of clinical methods and decision-making that have been thoroughly tested by properly controlled, peer-reviewed medical research to aid the delivery of optimal clinical care to patients.

What is the evidence-based review process?

Washington State contracts with the Center for Evidence-Based Policy (Oregon EPC), Oregon Health and Science University to independently review prescription drugs comparing the safety, efficacy, and effectiveness of drug classes and provide updates regularly. As a part of the review process, health care specialists:

  • Provide feedback to help ensure the concerns of patients and practitioners are thoroughly considered.
  • Develop key questions to guide the reviews, specifying the clinical conditions (diagnoses and disease(s)) of interest and define the population, interventions and outcomes (expected benefits, potential risks or harms).
  • Distinguish intermediate outcomes (e.g. laboratory test results or biometric measures) from true health outcomes (e.g. death, morbidity, functioning, and quality of life) and focus the research on true health outcomes when possible.

How is evidence found?

The Oregon Evidence-Based Practice Center uses several search techniques to gather clinical evidence for the reviews. These techniques include:

  • Searching major databases of the world's medical literature
  • Systematic reviews found in the Cochrane Collaboration Library
  • In addition, the Center can accept published or unpublished information from all reasonable sources as long as it can be publicly compared with information acquired by more traditional methods.

What is the process for determining acceptable research?

Research topics are determined through three-steps:

  1. Identify eligibility research.
  2. Identify relevant evidence.
  3. Prepare evidence-based practice tables.

Identify eligibility research and relevant evidence

Randomized controlled trials (RCT's) involving head-to-head comparisons of drugs are the optimal design for this process, but other evidence may be valuable or necessary for decision makers:

  • RCT's with placebo controls.
  • Large, well designed studies on populations not typically included in RCT's—for longer-term outcomes and potential adverse events.
  • Articles or titles and abstracts of research studies, reviewed against the eligibility criteria.

Decide which items to use or set aside

If an article or study is excluded from consideration, the reason for doing so is recorded as part of the final documentation.

Evidence practice tables

After the acceptable information sources are identified, the information is placed into detailed evidence tables that provide crucial information on study purpose and design, populations, diagnoses or conditions, interventions, outcomes, and other data.

The Oregon Evidence-Based Practice Center will coordinate communications between researchers and participating organizations to make certain that the eligibility criteria and evidence tables meet the needs of the participating organizations.

Peer reviews

Peer review is an integral part of the standards required by the Agency for Healthcare Research and Quality (AHRQ) for developing systematic reviews. Comments from reviewers are all given serious consideration. 

Peer reviewers

  • Comment on factual matters, presentation, interpretation, missing information, readability/usability, and similar matters.
  • Identify omissions, unwarranted conclusions or inferences, unintentional bias, inadvertent over-or under-emphasis, and unnecessarily tedious, obscure, or misleading writing.

Preparing the final review

  • During or following the peer review, the authors of the systematic review begin necessary revisions.
  • All legitimate points raised by the peer review are addressed in the final draft of the systematic review. For example, if reviewers note important missing data or studies, these are obtained and data from them are added to evidence tables and text, as appropriate.
  • Once the authors have completed the final evidence report, they will make it available for distribution as determined by the participating organizations.
  • The authors of the report may also submit the report, or a summary, for publication in a scientific journal. These journals further enhance the credibility and impact of the reports and of the evidence-based process within the scientific community.

What are evidence-based practice centers?

In 1997, the AHRQ began promoting evidence-based practice in everyday health care through establishment of 13 Evidence-Based Practice Centers (EPCs). Evidence-based practice is the conscientious use of current best evidence in making decisions about patient care. 

The EPC's develop evidence reports and technology assessments on clinical conditions or health services that are common, expensive, and/or are significant for the Medicare and Medicaid populations. With this program, AHRQ became the lead federal agency and a science partner with private and public organizations in their efforts to improve the quality, effectiveness, and appropriateness of health care by assisting the translation of evidence-based research findings into clinical practice.

AHRQ conducts and funds research that develops and presents evidence-based information on health care outcomes, quality, cost, use, and access. Included in AHRQ's legislative mandate is support for the establishment and distribution of scientific evidence. The research results assist practitioners, clinicians, patients, and policymakers in making evidence based decisions regarding the quality and effectiveness of health care.

More than 100 reviews and analyses of scientific literature have been conducted and used by care systems, organizations, health plans, public and private purchasers, states, and other entities as a foundation for developing and implementing their own clinical practice guidelines, clinical pathways, review criteria, performance measures, and other clinical quality improvement tools, as well as for formulating evidence-based policies related to specific health care technologies. Summaries of EPC reports may be reviewed by visiting AHRQ's website.