Nursing assignment

C H A P T E R 2

Evidence-based clinical practice guidelines Although most primary care visits are related to acute symptoms, the focus of this chapter is health screening conducted in primary care settings on asymptomatic adults and children and the process of developing evidence­based clinical practice guidelines for prevention, counseling, and screening interventions. The National Academy of Medicine, formerly the Institute of Medicine, defines clinical practice guidelines as “recommendations intended to optimize patient care, informed by a systematic review of evidence and an assessment of the benefits and harms of alternative care options.” The benefits of delivering evidence­based services include improving the quality of care, achieving desired health outcomes, and reducing health care costs. The ability to analyze and evaluate evidence requires a knowledge base and critical thinking skills.

Steps in evidence-based practice First, begin with a clinical problem. To examine the suitability of exploring a topic to develop practice guidelines, assess its public health importance. Criteria used include the burden of having a disorder poses to a population and the anticipated effectiveness of a preventive service or intervention to reduce that burden.

Second, pose a clinical question that focuses on a patient problem and potential preventive service. A useful format that incorporates key components of a well­constructed question is PICO: problem, intervention or exposure, comparison, and outcome.

An analytic framework can be useful in illustrating the chain of evidence that needs to be evaluated in moving from a screening or preventive intervention to health outcomes, such as improved quality and quantity of life (Fig. 2.1). Following the overarching question of “Does screening for X reduce morbidity and/or mortality?” (key question 1) is a series of questions to establish the clinical logic to support the implementation of a preventive service in a primary care setting:

1. Can a group at high risk for X be identified by clinical characteristics? 2. Are there accurate (i.e., sensitive and specific) screening tests available? 3. Are treatments available that make a difference in intermediate outcomes when the disease is caught

early or detected by screening? 4. Are treatments available that make a difference in morbidity or mortality when the condition is caught

early or detected by screening? 5. How strong is the association between the intermediate outcomes and patient health outcomes? 6. What are the harms of the screening test? 7. What are the harms of the treatment?

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FIGURE 2.1 Template of an analytic framework. See text discussion for the key questions that correspond to the numbers in the template. Source: (From U.S. Preventative Services Task Force. Methods and processes: procedure manual, Figure 3, n.d. Retrieved from https://www.uspreventiveservicestaskforce.org/Page/Name/section-3-topic-work-plan-development.)

When evaluating the chain of evidence, both certainty and magnitude of evidence for each key question is assessed to address the multiple opportunities for bias.

Third, select appropriate resources and conduct a literature search of each of the key questions that discuss comparisons of interventions and strategies used to examine outcomes of interest. Appraise the evidence for its validity and applicability. To begin a search, large databases such as PubMed or the Cochrane Library will access primary sources. Secondary sources such as the American College of Physicians (ACP) Journal Club, Essential Evidence Plus, and Clinical Evidence provide assessments of the original study (see Chapter 1). In analyzing the results, consider the following terms:

• Relative risk (RR) is the ratio of risk in the experimental group compared with the risk in the control group.

• Clinical versus statistical significance can be a matter of judgment and often depends on the magnitude of the effect being studied. “Is the difference between groups large enough to be worth achieving?”

• Odds ratio (OR) is the odds of previous exposure in a case divided by the odds of exposure in a control patient. For example, an OR of 3.0 means that the control cases were three times more likely to have been exposed than were treatment patients.

• Confidence intervals (CIs) are a measure of the precision of results. Wider CIs indicate lower precision. For example, “36 (CI, 27–51)” indicates that if the trial was repeated 100 times, 95% of the time the values would fall between 27 and 51.

Finally, apply this knowledge to patients and their preferences. It is important to assess whether the population from which the evidence is gathered matches that of a patient. For example, population­based mammography screening guidelines would not be applied to a person with a history of breast cancer.

Sources of evidence A hierarchy of evidence refers to study designs that allow for less bias or systematic error and may lead to a wrong conclusion. Randomized controlled clinical trials (RCTs) can provide sound evidence of cause and effect and can control for bias. Some limitations of RCTs are threats to the representativeness of the study population and consistency of implementation of the intervention. Meta­analysis examines a number of valid studies on a topic and mathematically combines the results to report them as if they were one large study. Expert opinion is evidence based on clinical experience, collective experience, and knowledge of professional organizations, such as the American Heart Association or the American College of Obstetrics and Gynecology. Case reports, cohort studies, and qualitative research provide less robust evidence of cause and effect and have less reliability and validity than higher levels of evidence.

Levels of prevention

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The three levels of prevention are primary, secondary, and tertiary. Primary prevention involves activities directed at improving general well­being while also providing specific protection for selected diseases. Interventions

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can include screening, counseling, or preventive medicines, such as immunizations or dental sealants. Counseling about behavioral risks, such as using seat belts or bicycle helmets, can reduce injury and death. A common model used to guide behavioral counseling is the 5 As model: ask about the behavior, advise about health risks and benefits of change, agree to set a goal, assist with identifying and overcoming barriers, and arrange for follow up.

The goal of secondary prevention is to identify and detect disease in its earliest stages before symptoms appear. Screening interventions can identify elevated blood pressure or risk of diabetes with a hemoglobin A1C measurement. With early detection and diagnosis, it may be possible to cure a disease, slow its progression, prevent or minimize complications, and limit disability.

Tertiary prevention programs aim to improve the quality of life for people with various conditions by limiting complications and disabilities, reducing the severity and progression of disease, and providing rehabilitation therapy to maximize functionality and self­sufficiency. Tertiary prevention can occur over a long period of time, such as optimizing treatment for chronic conditions such as asthma, physical or cognitive disability, and diabetes.

Population versus targeted screening Population screening includes all members of a particular population; for example, all newborns are screened for congenital hypothyroidism at birth. Targeted screening is more selective and focuses on a population at risk. An example is sexually transmitted infection (STI) screening done in sexually active adolescents and young adults in a specific age group (e.g., those 24 years and younger have the highest rates of infection) and who have increased risk factors for STI such as new or multiple sexual partners, inconsistent condom use, and sex work.

Ethical guidelines for screening Not all diseases or conditions are appropriate for screening. The purposes of screening must be ethically acceptable, information must be used for appropriate purposes, tests must be of high quality, individuals should know what is taking place and be informed of their results, counseling must be available to interpret results, and results must be kept confidential. Additionally, genomic medicine has created a new urgency in recognition and application of screening guidelines to assess the value of population screening for genetic susceptibility to diseases and conditions.

Guidelines for determining if a disease or condition warrants screening include the following:

Is the condition significant in the community? The condition must have a significant impact on the quality or quantity of life, must be measured using morbidity and mortality data, and must be measured by the quality of life. The incidence, or the number of new or undiagnosed cases, of the condition must be sufficient to justify the cost of screening.

Can the condition be screened? Tests that are acceptable to patients must be available at a reasonable cost to detect the condition in its asymptomatic period. Measures used to determine acceptability of tests include sensitivity (ability to provide a true positive) and specificity (ability to provide a true negative), as well as measures of reliability (reproducibility) and validity (does it measure what you think it measures?). Other considerations include potential harms of screening, such as labeling and stigma, or morbidity associated with the screening test, as well as patient preference.

Should the condition be screened? Before screening can be recommended, acceptable treatments must be available. Contextual variables, such as ethnicity and cultural beliefs and practices, socioeconomic conditions, and geographic location, need to be considered. The disease or condition must have an asymptomatic period and a period in which detection and treatment significantly improve health outcomes compared with a diagnosis obtained based on symptoms. Hypertension is an asymptomatic condition that affects a large number of adults, blood pressure can be measured accurately with minimal harm, and evidence­based risk reducing behavioral counseling and medications can improve health outcomes.

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United states preventive services task force The United States Preventive Services Task Force (USPSTF) was established in 1984 as an independent group of experts in prevention and evidence­based medicine. The work of the task force is to make recommendations about clinical preventive services such as screenings, counseling, and preventive medications.

The Task Force works with Evidence­Based Practice Centers (EPCs) that conduct in­depth systematic reviews of the available evidence and develop an analytic framework or research plan that includes a set of key questions and outcomes of interest that the review must answer (see Fig. 2.1). After deliberation with input and comments from the public and other experts, a recommendation is reached by calculating the balance between the certainty and magnitude of the net benefit (Table 2.1) and is then assigned a grade (Table 2.2). Box 2.1

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contains the six questions posed when evaluating evidence. The Task Force recommendations are considered the gold standard for clinical preventive services.

Table 2.1 Matrix for Arriving at a Grade Recommendation

MAGNITUDE OF NET BENEFIT CERTAINTY OF NET BENEFIT SUBSTANTIAL MODERATE SMALL ZERO/NEGATIVE

High A B C D

Moderate B B C D

Low Insufficient

From U.S. Preventive Services Task Force: Procedure manual, n.d. Retrieved from https://www.uspreventiveservicestaskforce.org/

Table 2.2 What the USPSTF Grades Mean and Suggestions for Practice

GRADE GRADE DEFINITIONS

The USPSTF recommends the service. There is high certainty that the net benefit is substantial.

A

B The USPSTF recommends the service. There is high certainty that the net benefit is moderate or there is moderate certainty that the net benefit is moderate to substantial.

D The USPSTF recommends against the service. There is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits.

C The USPSTF recommends selectively offering (or providing) this service to individual patients based on professional judgment and patient preferences. There is at least moderate certainty that the net benefit is small.

I Statement The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of the service. Evidence is lacking, of poor quality or conflicting, and the balance of benefits and harms cannot be determined.

SUGGESTIONS FOR PRACTICE

Offer or provide this service.

Offer or provide this service.

Offer or provide this service for selected patients depending on individual circumstances.

Discourage the use of this service.

Read “Clinical Considerations” section of USPSTF Recommendation Statement. If offered, patients should understand the uncertainty about the balance of benefits and harms.

Grade Definitions. U.S. Preventive Services Task Force, Rockville, MD. (Current as of November 2017). https://www. uspreventiveservicestaskforce.org/Page/Name/grade-definitions USPSTF, U.S. Preventative Services Task Force.

Box 2.1

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Quest ions to Consider When Evaluat ing Evidence

1. Do the studies have the appropriate research design to answer the key question(s)? 2. To what extent are the existing studies of high quality? 3. To what extent are the results of the studies generalizable to the general US primary care population

and situation? 4. How many studies have been conducted that address the key question(s)? 5. How consistent are the results of the studies? 6. Are there additional factors that assist with drawing conclusions?

Electronic Preventive Services Selector (ePSS) is a resource that practitioners can use to electronically access Task Force recommendations. It is designed to assist primary care practitioners in determining appropriate clinical preventative services for their patients (see http://epss.ahrq.gov/PDA/index.jsp).

The National Guideline Clearinghouse (www.guideline.gov) is a public resource maintained by the Agency for Health Care Research and Quality that provides summaries of guidelines from major medical and specialty organizations. To be included in the Clearinghouse, guidelines must meet criteria of incorporating a systematic review and including an assessment of the harms and benefits.

Summary Evidence alone was never meant to replace experience and intuition. There are always the human concerns to account for in clinical decision making. However, primary care practitioners will increasingly be engaged in delivering both preventive and acute care services. Practitioners need to be aware of evidence­based practice guidelines and make clinical decisions based on good­quality scientific evidence as well as clinical judgment considerations with individual patients and families.

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