Quality of Evidence Statement
HERC relies heavily on high quality evidence and
evidence-based guidelines in making prioritization decisions, coverage
guidances and other evidence-based reports.
The following source list illustrates how HERC and
the Value-based Benefits Subcommittee (VbBS) view various types of evidence. The existence of evidence in the form of a
high-quality study design does not necessarily mean that the overall evidence
on that topic will be considered high quality.
For instance, a high quality systematic review might find that the
available studies have significant potential for bias and may conclude there is
a low strength of evidence or insufficient evidence to support an intervention.
Lower quality evidence may sometimes be considered
in situations where higher quality evidence is difficult to obtain (for
example, in rare clinical conditions).
The commission includes other factors into its decision
making process, such as harms, treatment alternatives, health equity and the
needs of specific subgroups when relevant data exists.
HERC may consider various factors in evaluating a particular study,
including:
·
Potential for
bias
·
Clinical
significance of outcomes studied
·
Strength and
consistency of evidence, not just study quality
·
Study
relevance based on population and health system characteristics
·
Conflicts of
interests of the authors
The following
sources generally produce high quality evidence and are preferred by HERC:
- Agency for
Healthcare Research and Quality (AHRQ)
- Blue
Cross/Blue Shield Center for Clinical Effectiveness
- Canadian
Agency for Drugs and Technologies in Health (CADTH)
- Cochrane
Library (Wiley Online Library)
- Institute for
Clinical and Economic Review (ICER)
- Medicaid
Evidence-based Decisions Project (MED)
- National
Institute for Health and Care Excellence (NICE)
- Tufts
Cost-effectiveness Analysis Registry
- Veterans
Administration Evidence-based Synthesis Program (ESP)
- Washington State Health Technology Assessment Program
The following
types of study designs can be considered high quality and are preferred by
HERC:
- Systematic
reviews or metaanalyses of randomized controlled trials
- Systematic
reviews of prospective cohort studies
- Evidence-based
guidelines from trusted sources
The following
types of study designs/documents can be considered lower quality and are often
reviewed by HERC:
- Guidelines
issued by professional societies and advocacy organizations (e.g. American
Heart Association)
- Coverage
decisions by private health plans (e.g. Aetna)
- Well-conducted,
peer-reviewed individual studies (experimental or observational)
The following
types of evidence can be considered very low quality and are seldom reviewed by
HERC:
- Case reports,
case series
- Unpublished
studies (posters, abstracts, presentations, non-peer reviewed articles)
-
Individual studies that are poorly
conducted, do not appear in peer-reviewed journals, are inferior in design or
quality to other relevant literature, or duplicate information in other
materials under review by the Commission