Question

describe an evidence-based practice used in public health. How are interventions established as evidence-based in public health? discuss the importance of the chosen evidence-based practice to the field.

Answer 1

Evidence-based public health practice is the development, implementation, and evaluation of effective programs and policies in public health through application of principles of scientific reasoning, including systematic uses of data and information systems and appropriate use of behavioral science theory and program planning models.

An evidence based practice used in public health is the Community Guide conducted a review of the impact of 16 state laws that made it illegal to drive with a blood alcohol concentration (BAC) exceeding 0.08 percent. The review found that, following implementation of the law in these states, there was a mean decrease in fatalities due to alcohol-related motor vehicle crashes of 7 percent. The evidence review was used to justify federal legislation that linked highway funding for states to their enactment of laws lowering BAC to 0.8 percent.

Another example of the value of using evidence to guide public health practice is worksite risk assessments. In isolation, there is insufficient evidence to show that Assessment of Health Risk Factors (AHRF) is effective. In combination with health education and other interventions, however, a systematic review found strong evidence that AHRF is effective in improving one or more health behaviors or conditions in populations of workers.

The systematic review “Sexual Risk Behaviors and HIV Infection among Men Who Have Sex with Men and Women in China: Evidence from a Systematic Review and Meta-Analysis” by H.-Y. Wang et al. sheds light on potential transmission mechanism of HIV/AIDS in China, indicating that more emphasis must be put on prevention measures for men who have sex with men and women.

Interventions established in evidence based practice in public health are:

• A nomenclature to characterize interventions most likely to have meaningful public health impact based on the level of evidence, value, and experience in prior implementation.
• Recognition that the types of evidence that are suitable for evaluating an intervention vary, e.g., from randomized trials for specific technologies to health impact assessments for inter-sectoral policies.
• A general metric for benefit that can be used regardless of overall burden of a problem, e.g., an uncommon condition with a highly effective intervention may have “benefits that clearly exceed harms,” and an intervention for a common condition with a lower effectiveness but larger total impact can also be labeled this way.
• A way to consider context and practical experience in implementation.
• Identification of the kinds of research that would be needed to increase the level of categorization of an intervention.

Because it is unlikely that interventions will fit neatly into one category, interventions should be based on the BEST FIT, not on TOTAL FIT. For example, an intervention with demonstrated efficacy by the Cochrane Collaboration, but which has not been implemented outside of carefully controlled academic studies, would be categorized as “Promising” rather than “Proven” or “Likely effective.” The categories and criteria follow:

Proven:

Evidence of effectiveness (not efficacy) from an authoritative group (e.g., recommended by the Community Guide, Clinical Guide, Cochrane Collaboration)

Benefits clearly exceed harms

Used in public health practice: implemented in multiple settings and with different populations, suitable reach, feasible, evaluable, sustainable

Cost effectiveness reasonable

Some level of external validity (applicability in multiple settings and different populations) has been demonstrated

Likely Effective:

Sufficient evidence of effectiveness based on adequately designed peer-reviewed research studies, e.g., results of high-quality studies or evaluations, systematic reviews or health impact assessments

Benefits exceed harms

Used in public health practice: implemented in multiple settings, suitable reach, feasible, evaluable, sustainable

Cost effectiveness likely reasonable

Suitable for evidence-based review

Promising:

Evidence of effectiveness limited: based on non-peer reviewed studies, published reports, books, or expert consensus

Benefits may exceed harms

Used in public health practice: implemented in some setting, but suitability, reach, feasibility, sustainability are uncertain; may have evidence from process evaluations

Cost effectiveness uncertain

Needs further evaluation in controlled studies and community practice

Importance of evidence based practice in public health:

Within the context of limited funding, investment in an ineffective intervention means a lost chance to invest in something that works to improve health and/or prevent disease or injury. The public health field has often approached decision making about interventions with the belief that “if it sounds good, it must be good.”

” To counteract this tendency, the Centers for Disease Control and Prevention (CDC) is now commonly requiring that applicants who respond to Funding Opportunity Announcements use evidence-based interventions supported by credible sources, or provide independent justification.

At the present time, a number of interventions are commonly used for which we do not yet have adequate evidence of effectiveness. The evidence-base must be strengthened for a wide range of interventions, including school-based programs to promote nutrition and physical activity, state or community-wide promotion of sealants to reduce dental caries, and client or family incentives to increase demand for vaccination, all of which lack sufficient evidence to determine whether or not they are effective.

1. Tradeoffs between internal and external validity: Due to the wide-scale adoption of the CONSORT reporting criteria for randomized clinical trials and related methodological quality rating scales (e.g., TREND) for non-randomized trials, there has been an increased focus on the methodological quality of research reports.Adoption of these criteria (e.g., randomization, double-blinding, and other controls over potential confounding factors) have led to enhanced internal validity and analytic reporting quality

2. Systematic reviews and guideline development: The foundation of the EBM approach is the “systematic review,” epitomized for many by the Cochrane Collaboration meta-analyses. Systematic reviews summarize the results of available, carefully designed and executed studies. They provide an assessment of the quality of evidence and the effectiveness (net benefit or balance of benefits and harms) of health interventions. Systematic reviews of high-quality studies are important for assessing specific interventions.

3. Integrating the Existing Science into Implementation Processes:They can be informative about efficacy and average effect sizes under ideal circumstances in research settings (internal validity). They can also help to identify best practices and rule out approaches that are unlikely to be useful.