Advanced searches left 3/3
Search only database of 7.4 mil and more summaries

Levels Of Evidence

Summarized by PlexPage
Last Updated: 16 September 2020

* If you want to update the article please login/register

General | Latest Info

Critical care nurses have a responsibility to use Evidence - base practices in their patient care. To ensure their actions will produce desired outcomes, critical care nurses must use the strongest evidence available to support patient care. 1 Determining what qualifies as strong evidence can be challenging. According to the Agency for Healthcare Research and Quality, evidential strength includes three elements: quality, quantity, and consistency. 2 Quality is the most challenging element nurses must evaluate when assessing the strength of evidence for a topic. Quality refers to methods used to ensure that results are valid and not influenced by bias or occurring by chance. 2 One component of quality is the level of evidence. Quantity is evaluated by considering the number of studies on topic, size of studies, and impact of studied treatments. Consistency is the easiest of these elements to understand; for evidence to be strong, similar findings should be reported across multiple sources. 2 this Series will provide basic guidance for appraising evidence. However, this is only one step in the Evidence - base practice process, which includes complexities that this Series will not address. Many resources exist for nurses to develop their critical appraisal skills and strengthen their understanding of the EBP process. For example, American Journal of Nursing published a 12 - article series outlining a step - by - step approach to EBP. 3 variety of evidence hierarchies exist to evaluate the level of evidence. 1 To apply these hierarchies, nurses must have working knowledge of research design. This initial Evaluating Evidence Series installment will provide nurses with basic understanding of research design to appraise the level of evidence source. This article will review appraisal of experimental research, which includes randomized controlled trials and quasi - experimental research. Future installments in this series will address nonexperimental research appraisal and finally levels of nonresearch evidence.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

The evidence pyramid

Systematic review focuses on clinical topics and answers specific question. Thorough literature search is conducted to identify all studies using sound methodology. Studies are evaluated and results are summarized according to preselected criteria. No quantitative statistical analysis is done. Meta analysis carefully examines the number of credible studies on topic and combines results using quantitative statistical methodology. It is higher quality systematic review and, therefore, is at the top of the pyramid. Use databases above and limit your search to systematic review and meta analysis. Randomized controlled trial is a carefully planned project that studies the effect of therapy on patients. It includes methodologies that reduce the potential for bias and that allow for comparison between intervention groups and control groups. Cohort Study takes large population and follows patients who have specific condition or receive particular treatment over time and compares them with another group that has not been affected by condition or treatment being study. Cohort studies are observational and not as reliable as randomized control studies since two groups may differ in ways other than in variable under study. A Case control study is an observational study in which patients who already have specific condition are compared with people who do not. There is no randomization. These studies are usually less reliable than randomized controlled trials and Cohort studies because showing statistical relationship does not mean that one factor necessarily causes another. These studies look back into time and patient records are usually review. Case report consists of collections of reports on treatment of individual patients or reports on single patient. Because they are reports of cases and use no control groups with which to compare outcomes, they have no statistical validity. Bio - Medical Library at University of Minnesota has created an excellent visual guide to basic research Study design in the hierarchy of Evidence as Center for Evidence - base Medicine.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Internal Validity

These levels of evidence apply only to studies of assessing the accuracy of diagnostic or screening tests. To assess the overall effectiveness of diagnostic tests, there also needs to be consideration of the impact of tests on patient management and health outcomes. The Evidence hierarchy given in the Intervention column should be used to assess the impact of diagnostic tests on health outcomes relative to existing method of diagnosis / comparator test. The Evidence hierarchy given in the Screening column should be used to assess the impact of screening tests on health outcomes relative to no screening or opportunistic screening. Systematic Review will only be assigned level of evidence as high as studies it contain, excepting where those studies are of Level II Evidence. Systematic Reviews of Level II Evidence provide more data than individual studies and any Meta - Analyses will increase precision of overall results, reducing the likelihood that results are affected by chance. Systematic Reviews of lower Level Evidence present results of likely poor Internal Validity and thus are rat on likelihood that results have been affected by bias, rather than whether the systematic review itself is of good quality. Systematic Review Quality should be assessed separately. Systematic Review should consist of at least two studies. In Systematic Reviews that include different study designs, overall level of evidence should relate to each individual outcome / result, as different studies might contribute to each different outcome. Well - Design population base Case - Control Studies do capture population with a representative spectrum of disease and thus fulfil requirements for valid assembly of patients. However, in some cases, population assemble is not representative of the use of tests in practice. In diagnostic Case - Control Studies, select samples of patients already known to have disease are compared with a separate group of normal / healthy people known to be free of disease. In this situation, patients with borderline or mild expressions of disease, and conditions mimicking disease are exclude, which can lead to exaggeration of both sensitivity and specificity. This is called spectrum bias or spectrum effect because the spectrum of study participants will not be representative of patients seen in practice. Note: Assessment of comparative harms / safety should occur according to the hierarchy presented for each of the research questions, with proviso that this assessment occur within the context of the topic being assess. Some harms are rare and cannot feasibly be captured within randomise Controlled Trials, in which case, lower levels of evidence may be the only type of evidence that is practically achievable; physical harms and psychological harms may need to be addrest by different study designs; harms from diagnostic testing include likelihood of false positive and false negative results; harms from Screening include likelihood of false alarm and false reassurance results.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

History of Levels of Evidence

Levels of evidence were originally described in a report by the Canadian Task Force on Periodic Health Examination in 1979. 7 report purpose was to develop recommendations on Periodic Health exam and base those recommendations on evidence in medical literature. Authors develop a system of rating evidence when determining the effectiveness of particular intervention. Evidence was taken into account when grading recommendations. For example, grade recommendation was given if there was good evidence to support the recommendation that conditions be included in the Periodic Health exam. Levels of evidence were further described and expanded by Sackett 8 in an article on levels of evidence for antithrombotic agents in 1989. Both systems place randomized controlled trials at the highest level and case series or expert opinions at the lowest level. Hierarchies rank studies according to probability of bias. Rcts are given the highest level because they are designed to be unbiased and have less risk of systematic errors. For example, by randomly allocating subjects to two or more treatment groups, these types of studies also randomize confounding factors that may bias results. Case series or expert opinion is often bias by authors ' experience or opinions and there is no control of confounding factors.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Modification of levels

Therapeutically relevant clinical Research Evidence can be broadly categorized into studies of observational nature and those that have structured experimental study design. Experimental studies, which include randomized controlled trials and methodologically sound meta - analyses of RCTs, are positioned at the top of the hierarchy. Although nomenclature may change across different categories of research, fundamental premise of LSE stratification remains the samean: organized progression from low to high along the spectrum of internal / external scientific validity. Bias in study design can confound results of investigation and lead to misrepresentation of true implications of intervention / treatment being study. Rct is clinical trial design intended to minimize bias by randomly allocating study participants to two or more interventions or treatment arms and often blinding patients and investigators from knowing which intervention an individual is receiving. Within this paradigm, each treatment arm may represent a different drug, device, or procedure. It may also represent different ways of applying or using process, device, procedure, or placebo. By limiting any opportunity for patients, clinicians, or investigators to choose which arm of trial participants will be assigned to, RCTs effectively minimize bias through the process of randomizing both known and unknown prognostic variables. Above - mention blinding process thus allows less biased estimate of treatment effect that has enabled RCTs to revolutionize medical research, achieving the status of gold standard for therapeutic research and holding top position in the EBM hierarchy of LSEs. Results from RCTs, although considered the most robust and reliable form of evidence, are not always easily translatable or applicable across diverse clinical settings. Moreover, not every medical decision requires data from RCT. Implementation of RCT findings may be challenging at the single - institution level, primarily because of procedural, work - flow, and other institution - specific factors. Well - designed observational studies are recognized as Level IIa, IIb, or III evidence and generally are easier to conduct than RCTs, but still provide meaningful clinical evidence. Additionally, observational studies may lay the foundation for definitive RCT to be conduct. Cohort and case - control studies are two primary types of observational studies that can demonstrate important associations between exposure and disease. Place slightly above case - control studies in the LSE hierarchy, cohort studies can be both prospective and retrospective in nature. Prospective cohort studies observe two groups of populationsone, group with risk or prognostic factor of interest and the second group without. These populations are followed over variable periods of time to observe development of disease or specific outcome among those with risk factors and those without. Prospective cohort studies can be tailored to collect data regarding exposure to any specific or rare disease and can be designed to observe multiple outcomes for any given exposure or intervention. Retrospective cohort studies, on the other hand, are historic in nature and look in to the past to analyze disease development within specific groups of subjects based on their known exposure status.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Plastic surgery and EBM

The field of plastic surgery has been slow to adopt evidence - base medicine. This was demonstrated in a paper examining the level of evidence of papers published in PRS. 19 authors assigned levels of evidence to papers published in PRS over a 20 year period. The majority of studies were level 4 or 5, which denote case series and case reports. Although the results are disappointing, there was some improvement over time. By 2003, there were more level 1studies and fewer level 4 and 5 studies. A recent analysis looks at the number of level 1 studies in 5 different plastic surgery journals from 1978 - 2009. Authors define level 1 studies as RCTs and meta - analysis and restrict their search to these studies. The number of level 1 studies increased from 1 in 1978 to 32 in 2009. 20 From these results, we see that the field of plastic surgery is improving level of evidence but still has a way to go, especially in improving the quality of studies publish. For example, approximately a third of studies involve double blinding, but the majority do not randomize subjects, describe the randomization process, or perform power analysis. Power analysis is another area of concern in plastic surgery. A review of plastic surgery literature finds that the majority of published studies have inadequate power to detect moderate to large differences between treatment groups. 21 No matter what level of evidence for study, if it is under power, interpretation of results is questionable. Although the goal is to improve the overall level of evidence in plastic surgery, this does not mean that all lower level evidence should be discard. Case series and case reports are important for hypothesis generation and can lead to more controlled studies. Additionally, in the face of overwhelming evidence to support treatment, such as use of antibiotics for wound infections, there is no need for RCT.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Sources

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

logo

Plex.page is an Online Knowledge, where all the summarized are written by a machine. We aim to collect all the knowledge the World Wide Web has to offer.

Partners:
Nvidia inception logo
jooble logo

© All rights reserved
2021 made by Algoritmi Vision Inc.

If your domain is listed as one of the sources on any summary, you can consider participating in the "Online Knowledge" program, if you want to proceed, please follow these instructions to apply.
However, if you still want us to remove all links leading to your domain from Plex.page and never use your website as a source, please follow these instructions.