The Evidence Base

Definition of Evidence-Based Practice

The term evidence-based practice was coined in the 1990s and has been widely embraced by most healthcare disciplines. Evidence-based practice (EBP) integrates the best scientific research evidence with clinical expertise of healthcare practitioners and patient and/or family preferences to facilitate clinical decision making. Decisions are based upon factors from each domain: the clinical situation, the patient and family preferences, and the research evidence, and individualized to the circumstances. There are multiple models of EBP between and within healthcare disciplines. The conceptual model described by Satterfield et al is a interdisciplinary model based upon the strengths of EBP models and processes from medicine, nursing, psychology, social work, and public health ( Fig. 9-1 ). The strength of pediatric palliative care practice stems from the interdisciplinary collaboration of multiple healthcare disciplines. EBP is an approach to problem solving that addresses the needs of the organization, the individual practitioner, the patient, and the family to promote high-quality healthcare. Organizational experiences of quality improvement and financial data, combined with clinical research, clinical experience, and patient and/or family preferences promote shared decision making based upon all contextual factors. Palliative care is a relatively young discipline and pediatric palliative care is even younger. The evidence base in palliative care is not robust and there is a paucity of evidence specific to pediatrics.

Evidence-based practice is a process as well as a practice descriptor. The process involves defining a practice issue, searching the literature for current research, critically appraising the evidence, synthesizing the evidence to make recommendations for changes in practice, implementing the recommended changes, and evaluating the outcomes. EBP relies on a holistic approach to decision making based less upon expert opinion. Translation of the domains of EBP, scientific research, clinical expertise, and patient and/or family preferences into practice produces products such as changes in clinical practice, clinical guidelines, organizational standards of practice, and opportunities for fostering a research agenda in pediatric palliative care.

The healthcare professions involved in pediatric palliative care, including medicine, nursing, psychology, social work, child life and others, are a science and applied professions with equal contributions to the art and science of clinical practice. The perceived value of evidence may vary depending upon the discipline of practice. Traditional evidence-based medicine relies heavily on randomized clinical trials, yet this approach to generations of evidence is not as practical for pediatric palliative care, where a vulnerable patient population is often excluded from clinical research. Most palliative care research is adult-focused and this is one of the challenges to creating pediatric palliative care evidence-based guidelines ( Table 9-1 ). The narrow scope of pediatric palliative care may be too focused for most standard literature search engines. The value of expert clinicians within and between disciplines is unclear and often underestimated in determining EBP recommendations. Evidence must be defined broadly and considered within the context of the specific clinical issue. Evidence is published in a wide variety of journals pertinent to a spectrum of diseases.

Levels of Evidence Used in Practice Guideline Development and Implications for Pediatrics

The development of clinical practice guidelines for the management of a variety of diseases and conditions brings together experts to review and summarize current evidence, evaluate the quality of the evidence, and make recommendations for practice. The National Consensus Project for Quality Palliative Care (NCP) brought together leaders of five national organizations representing hospice and palliative care. This task force followed a rigorous process of evidence review and consensus development to produce the Clinical Practice Guidelines for Quality Palliative Care in 2003, with an update in 2009. The National Quality Forum, a private, nonprofit membership organization recognized for its national leadership in healthcare quality improvement, reviewed and adopted the NCP guidelines as the basis for its Framework for Palliative and Hospice Care Quality Measurement and Reporting. Clinicians and clinical organizations identified 38 best practices for implementation. Quality indicators are being developed to evaluate the impact of those practices.

All clinical recommendations are not equivalent. Their importance will vary with the likelihood of significant benefit or harm avoidance to the patient. The evidence and experience that provides the foundation for the recommendation will also vary in quality depending on the methods used to produce the results. Frameworks have been developed to rate these factors within a set of clinical guidelines. These frameworks use a letter designation for how strongly the practice recommendation is made or how uniform the consensus is for the recommendation, and a numeral designation for the quality of the evidence supporting that recommendation ( Tables 9-2 and 9-3 ).

The randomized controlled trial (RCT) is considered the gold standard for evaluating the effect of treatment interventions. The RCT study design minimizes the likelihood that bias in the selection of research participants or in the evaluation of the study outcomes will influence the results. RCTs are prospective interventions, providing evidence of cause and effect.

Other research designs that generate evidence include prospective non-randomized trials and observational cohorts; retrospective record reviews, interviews, or surveys; cross sectional studies; qualitative, ethnographic research; and case series or reports. Observational studies may yield associations but cannot determine cause and effect; hence, they are rated lower than RCTs for quality of evidence to support a particular clinical intervention. Similarly, qualitative studies are considered a source of credible evidence but are considered less informative about cause and effects than RCTs. Expert consensus is the least-rigorous level of evidence but recognizes the knowledge accumulated through serial observations by experts in the field. It is therefore possible to have strong recommendations that are supported only by expert opinion.

The Working Group on Antiretroviral Therapy and Medical Management of HIV-Infected Children is made up of experts from different disciplines. This group is rating their clinical recommendations in the manner described above. However, they recognized that some of their strongest recommendations were based on the adoption of practices proved efficacious in rigorous, well-powered clinical trials of adult patients with minimal supporting evidence in a pediatric population. Following the framework above would result in a rating the supporting evidence as Level III—Expert Opinion. Yet this did not adequately reflect the high quality and compelling results of the evidence that could and should be applied to children with the same life-threatening condition. Therefore the Working Group has modified its rating system to recognize the application in pediatrics of evidence developed in studies of adult patients. An asterisk is added to the numeral to designate that the primary evidence is taken from adult studies and that there is evidence in smaller and more focused pediatric studies that support its application in children.

Ideally, strong evidence underpins all treatment decisions, yet many clinical situations still demand that clinicians use their best professional judgment in the absence of conclusive evidence. This is precisely the definition of evidence-based practice: the integration of individual clinical expertise with the best available external clinical evidence in the care of individual patients.

There are several reasons why a conclusive level of evidence is difficult to obtain in pediatric palliative care. First, designing and conducting randomized trials with seriously ill or dying patients of any age requires meticulous attention to the treatment alternatives, the burden of outcome assessment, and the need for short-term outcome measures given the likelihood that patients may die early in the study. Second, many important questions in palliative care are not answerable through randomized clinical trial design. Finally, the questions that can be answered through RCT, such as comparing two medications for treatment of a specific symptom, are more difficult to conduct in pediatric populations due to a smaller sample of eligible patients, the wide variation in physical development associated with age, and the diversity of disease conditions. Although not ideal, pediatric clinicians must sometimes make treatment decisions based on strong evidence obtained in adult trials and the presumption that there is likelihood of similar benefit in children.

Searching the Palliative Care Literature

Palliative care is a broad category of clinical practice, crossing disciplines, diseases, and ages from prenatal to geriatrics. Thus, literature specific to pediatric palliative care is difficult to identify. Defining a search filter for evidence is essential. Medical Subject Headings (MeSH) terms may not elucidate the true intent of palliative care due to the diffuse nature of the subject area. Using a medical librarian skilled in database searches will help clinicians narrow the focus and screen articles quickly for inclusion or exclusion in review. Hand searches will often be necessary to augment electronic database searches. Multiple text words and phrases are needed in addition to traditional MeSH terms ( Table 9-4 ). In a 2007 study, use of this search strategy provided 64.7 percent sensitivity, 92 percent specificity, and 91.1 percent accuracy. Information pertinent to searches specific to pediatric palliative care are lacking. However, using the key terms listed in Table 9-4 does yield inclusion of pediatric literature. It is encouraging that the number of clinical trials found in the literature is increasing, although still limited. In a recent systematic review, only 7.22 percent of palliative care literature was noted to be clinical trials. Most palliative care research is qualitative or descriptive in nature, thus placing the level of evidence at Level III. Clinicians are then challenged to use this level of evidence in conjunction with clinical expertise and patient and/or family preferences to optimize decision making.