One of the trends in modern medical practice is the growing popularity of evidence based medicine (EBM), also called evidence based health care. In the United States the leading advocate of EBM is theUS Preventive Services Task Force. Their methodology is widely used within the Department of Health and Human Services. Under the EBM protocol, studies are reviewed and assigned a rating:
Level I: Evidence obtained from at least one properly designed randomized controlled trial.Level II-1: Evidence obtained from well-designed controlled trials without randomization.Level II-2: Evidence obtained from well-designed cohort or case-control analytic studies, preferably from more than one center or research group.Level II-3: Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled trials might also be regarded as this type of evidence.Level III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.
From these studies possible interventions are rated on a scale of efficacy
- Grade A. Recommended. There is high certainty that the net benefit is substantial.
- Grade B. Recommended. There is high certainty that the net benefit is moderate or there is moderate certainty that the net benefit is moderate to substantial.
- Grade C. No recommendation. Clinicians may provide the service to selected patients depending on individual circumstances. However, for most individuals without signs or symptoms there is likely to be only a small benefit.
- Grade D. The Task Force recommends against this service. There is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits.
- I statement. The current evidence is insufficient to assess the balance of benefits and harms.
Via: Red State
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