Misconceptions, challenges, uncertainty, and progress in guideline recommendations

Although the quality of clinical practice guidelines has improved over the last decade, current guideline systems have limitations that reduce their validity and limit their acceptance. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) working group, a worldwide collaboration of guideline developers, methodologists, and clinicians, has constructed a system for developing guidelines that addresses these shortcomings. The system includes a transparent and rigorous methodology for rating the quality of evidence, an explicit balancing of benefits and harms of healthcare interventions, an explicit acknowledgement of the values and preferences that underlie the recommendations, and whether the intervention represents a wise use of resources. These four elements determine whether a recommendation is strong or weak. A guideline panel offers strong recommendations when virtually all informed patients would choose the same management strategy. Weak recommendations imply that choices will differ across the range of patient values and preferences. The GRADE system has been tested in multiple practice settings and for a large spectrum of questions, refined and re-evaluated to ensure that it captures the complex issues involved in evidence assessment and grading recommendations while maintaining simplicity and practicality. Many guideline organizations and medical societies have endorsed the system and adopted it for their guideline processes.     

A case for clarity, consistency, and helpfulness: state-of-the-art clinical practice guidelines in endocrinology using the grading of recommendations, assessment, development, and evaluation system

CONTEXT: The Endocrine Society, and a growing number of other organizations, have adopted the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to develop clinical practice guidelines and grade the strength of recommendations and the quality of the evidence. Despite the use of GRADE in several of The Endocrine Society's clinical practice guidelines, endocrinologists have not had access to a context-specific discussion of this system and its merits. EVIDENCE ACQUISITION: The authors are involved in the development of the GRADE standard and its application to The Endocrine Society clinical practice guidelines. Examples were extracted from these guidelines to illustrate how this grading system enhances the quality of practice guidelines. EVIDENCE SYNTHESIS: We summarized and described the components of the GRADE system, and discussed the features of GRADE that help bring clarity and consistency to guideline documents, making them more helpful to practicing clinicians and their patients with endocrine disorders. CONCLUSIONS: GRADE describes the quality of the evidence using four levels: very low, low, moderate, and high quality. Recommendations can be either strong ("we recommend") or weak ("we suggest"), and this strength reflects the confidence that guideline panel members have that patients who receive recommended care will be better off. The separation of the quality of the evidence from the strength of the recommendation recognizes the role that values and preferences, as well as clinical and social circumstances, play in formulating practice recommendations.     

Grading strength of recommendations and quality of evidence in clinical guidelines: report from an american college of chest physicians task force

While grading the strength of recommendations and the quality of underlying evidence enhances the usefulness of clinical guidelines, the profusion of guideline grading systems undermines the value of the grading exercise. An American College of Chest Physicians (ACCP) task force formulated the criteria for a grading system to be utilized in all ACCP guidelines that included simplicity and transparency, explicitness of methodology, and consistency with current methodological approaches to the grading process. The working group examined currently available systems, and ultimately modified an approach formulated by the international GRADE group. The grading scheme classifies recommendations as strong (grade 1) or weak (grade 2), according to the balance among benefits, risks, burdens, and possibly cost, and the degree of confidence in estimates of benefits, risks, and burdens. The system classifies quality of evidence as high (grade A), moderate (grade B), or low (grade C) according to factors that include the study design, the consistency of the results, and the directness of the evidence. For all future ACCP guidelines, The College has adopted a simple, transparent approach to grading recommendations that is consistent with current developments in the field. The trend toward uniformity of approaches to grading will enhance the usefulness of practice guidelines for clinicians.     

Emerging concepts in clinical practice guidelines

The German Society for Digestive and Metabolic Diseases (Deutsche Gesellschaft für Verdauungs- und Stoffwechselkrankheiten, DGVS) has already published an impressive number of clinical practice guidelines, with more topics currently being under development. The guideline method within the DGVS as well as between medical professional societies varies greatly. In particular, the levels of evidence as well as the grades of recommendations are often applied very differently. Most guidelines in Germany use the grades of the US Agency for Health Care Policy and Research (AHCPR), which were first published in 1992. Some newer guidelines, e.g., the ulcerative colitis guideline of the DGVS or the guidelines of the German Diabetes Association, try to circumvent problems of this method. They adopted variations of the very simple AHCPR grades. Sometimes these new grading methods have serious shortcomings too. They may not be reproducible, ignore important parts of the consensus process, can only be applied to therapeutic interventions, or they do not adequately distinguish between the strength of a recommendation and the quality of evidence. Meanwhile, an enormous number of different and partially contradictory methodologies for the grading of guideline recommendations are being used. In the GRADE working group several renowned clinical epidemiologists came together to develop a uniform grading systematic that avoids the problems of earlier guideline methods. With GRADE first the quality of evidence is assessed in a systematic manner. The quality of each study plays an important role in this process. Hence randomised trials of poor quality can end up with a lower overall quality rating than well performed observational trials. The strength of recommendation is based on the balance between the expected benefit and harm of the intervention in the respective population for which the recommendations of the guideline are made. The quality of evidence is only one factor contributing to the strength of recommendation. The GRADE method can be more cumbersome in its application compared to older methods. Nevertheless, more and more organisations are adopting GRADE for their guidelines and recommendations. Possibly the DGVS guidelines could benefit from this new system too.     

A Framework for Crafting Clinical Practice Guidelines that are Relevant to the Care and Management of People with Multimorbidity

Many patients of all ages have multiple conditions, yet clinicians often lack explicit guidance on how to approach clinical decision-making for such people. Most recommendations from clinical practice guidelines (CPGs) focus on the management of single diseases, and may be harmful or impractical for patients with multimorbidity. A major barrier to the development of guidance for people with multimorbidity stems from the fact that the evidence underlying CPGs derives from studies predominantly focused on the management of a single disease. In this paper, the investigators from the Improving Guidelines for Multimorbid Patients Study Group present consensus-based recommendations for guideline developers to make guidelines more useful for the care of people with multimorbidity. In an iterative process informed by review of key literature and experience, we drafted a list of issues and possible approaches for addressing important coexisting conditions in each step of the guideline development process, with a focus on considering relevant interactions between the conditions, their treatments and their outcomes. The recommended approaches address consideration of coexisting conditions at all major steps in CPG development, from nominating and scoping the topic, commissioning the work group, refining key questions, ranking importance of outcomes, conducting systematic reviews, assessing quality of evidence and applicability, summarizing benefits and harms, to formulating recommendations and grading their strength. The list of issues and recommendations was reviewed and refined iteratively by stakeholders. This framework acknowledges the challenges faced by CPG developers who must make complex judgments in the absence of high-quality or direct evidence. These recommendations require validation through implementation, evaluation and refinement.     

Oral pharmacologic treatment of type 2 diabetes mellitus: a clinical practice guideline from the American College of Physicians

DESCRIPTION: The American College of Physicians (ACP) developed this guideline to present the evidence and provide clinical recommendations on the comparative effectiveness and safety of type 2 diabetes medications. METHODS: This guideline is based on a systematic evidence review evaluating literature published on this topic from 1966 through April 2010 that was identified by using MEDLINE (updated through December 2010), EMBASE, and the Cochrane Central Register of Controlled Trials. Searches were limited to English-language publications. The clinical outcomes evaluated for this guideline included all-cause mortality, cardiovascular morbidity and mortality, cerebrovascular morbidity, neuropathy, nephropathy, and retinopathy. This guideline grades the evidence and recommendations by using the American College of Physicians clinical practice guidelines grading system. RECOMMENDATION 1: ACP recommends that clinicians add oral pharmacologic therapy in patients diagnosed with type 2 diabetes when lifestyle modifications, including diet, exercise, and weight loss, have failed to adequately improve hyperglycemia (Grade: strong recommendation; high-quality evidence). RECOMMENDATION 2: ACP recommends that clinicians prescribe monotherapy with metformin for initial pharmacologic therapy to treat most patients with type 2 diabetes (Grade: strong recommendation; high-quality evidence). RECOMMENDATION 3: ACP recommends that clinicians add a second agent to metformin to treat patients with persistent hyperglycemia when lifestyle modifications and monotherapy with metformin fail to control hyperglycemia (Grade: strong recommendation; high-quality evidence).     

Practice guidelines, a new reality in medicine. II. Methods of developing guidelines.

Current methods for developing practice guidelines include informal consensus development, formal consensus development, evidence-based guideline development, and explicit guideline development. Informal consensus development is the oldest and most common approach, but guidelines produced in this manner are often of poor quality and lack adequate documentation of methods. Formal consensus development uses a systematic approach to assess expert opinion and to reach agreement on recommendations. Evidence-based guideline development links recommendations directly to scientific evidence of effectiveness; rules of evidence are emphasized over expert opinion in making recommendations. Explicit guideline development clarifies the rationale by specifying the potential benefits, harms, and costs of available interventions; estimating the possibility of the outcomes; and comparing the desirability of the outcomes based on patient preferences. Steps in the development of practice guidelines include introductory decisions (selection of topic and panel members, clarification of purpose); assessments of clinical appropriateness (review of scientific evidence and expert opinion); assessment of public policy issues (resource limitations, feasibility issues); and guideline document development and evaluation (drafting of document, peer review, and pretesting).     

The American Society of Hematology 2011 evidence-based practice guideline for immune thrombocytopenia

Immune thrombocytopenia (ITP) is commonly encountered in clinical practice. In 1996 the American Society of Hematology published a landmark guidance paper designed to assist clinicians in the management of this disorder. Since 1996 there have been numerous advances in the management of both adult and pediatric ITP. These changes mandated an update in the guidelines. This guideline uses a rigorous, evidence-based approach to the location, interpretation, and presentation of the available evidence. We have endeavored to identify, abstract, and present all available methodologically rigorous data informing the treatment of ITP. We provide evidence-based treatment recommendations using the GRADE system in those areas in which such evidence exists. We do not provide evidence in those areas in which evidence is lacking, or is of lower quality--interested readers are referred to a number of recent, consensus-based recommendations for expert opinion in these clinical areas. Our review identified the need for additional studies in many key areas of the therapy of ITP such as comparative studies of "front-line" therapy for ITP, the management of serious bleeding in patients with ITP, and studies that will provide guidance about which therapy should be used as salvage therapy for patients after failure of a first-line intervention.     

Canadian Thoracic Society: Presenting a new process for clinical practice guideline production

A key mandate of the Canadian Thoracic Society (CTS) is to promote evidence-based respiratory care through clinical practice guidelines (CPGs). To improve the quality and validity of the production, dissemination and implementation of its CPGs, the CTS has revised its guideline process and has created the Canadian Respiratory Guidelines Committee to oversee this process. The present document outlines the basic methodological tools and principles of the new CTS guideline production process. Important features include standard methods for choosing and formulating optimal questions and for finding, appraising, and summarizing the evidence; use of the Grading of Recommendations Assessment, Development and Evaluation system for rating the quality of evidence and strength of recommendations; use of the Appraisal of Guidelines for Research and Evaluation instrument for quality control during and after guideline development and for appraisal of other guidelines; use of the ADAPTE process for adaptation of existing guidelines to the local context; and use of the GuideLine Implementability Appraisal tool to augment implementability of guidelines. The CTS has also committed to develop guidelines in new areas, an annual guideline review cycle, and a new formal process for dissemination and implementation. Ultimately, it is anticipated that these changes will have a significant impact on the quality of care and clinical outcomes of individuals suffering from respiratory diseases across Canada.     

Guidelines for antimicrobial treatment of uncomplicated acute bacterial cystitis and acute pyelonephritis in women. Infectious Diseases Society of America (IDSA).

This is part of the series of practice guidelines commissioned by the Infectious Diseases Society of America (IDSA) through its Practice Guidelines Committee. The purpose of this guideline is to provide assistance to clinicians in the diagnosis and treatment of two specific types of urinary tract infections (UTIs): uncomplicated, acute, symptomatic bacterial cystitis and acute pyelonephritis in women. The guideline does not contain recommendations for asymptomatic bacteriuria, complicated UTIs, Foley catheter-associated infections, UTIs in men or children, or prostatitis. The targeted providers are internists and family practitioners. The targeted groups are immunocompetent women. Criteria are specified for determining whether the inpatient or outpatient setting is appropriate for treatment. Differences from other guidelines written on this topic include use of laboratory criteria for diagnosis and approach to antimicrobial therapy. Panel members represented experts in adult infectious diseases and urology. The guidelines are evidence-based. A standard ranking system is used for the strength of the recommendation and the quality of the evidence cited in the literature reviewed. The document has been subjected to external review by peer reviewers as well as by the Practice Guidelines Committee and was approved by the IDSA Council, the sponsor and supporter of the guideline. The American Urologic Association and the European Society of Clinical Microbiology and Infectious Diseases have endorsed it. An executive summary and tables highlight the major recommendations. Performance measures are described to aid in monitoring compliance with the guideline. The guideline will be listed on the IDSA home page at http://www.idsociety.org It will be evaluated for updating in 2 years.     

Management of Thyroid Dysfunction during Pregnancy and Postpartum: An Endocrine Society Clinical Practice Guideline

Objective: The aim was to update the guidelines for the management of thyroid dysfunction during pregnancy and postpartum published previously in 2007. A summary of changes between the 2007 and 2012 version is identified in the Supplemental Data (published on The Endocrine Society's Journals Online web site at http://jcem.endojournals.org). Evidence: This evidence-based guideline was developed according to the U.S. Preventive Service Task Force, grading items level A, B, C, D, or I, on the basis of the strength of evidence and magnitude of net benefit (benefits minus harms) as well as the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence. Consensus Process: The guideline was developed through a series of e-mails, conference calls, and one face-to-face meeting. An initial draft was prepared by the Task Force, with the help of a medical writer, and reviewed and commented on by members of The Endocrine Society, Asia and Oceania Thyroid Association, and the Latin American Thyroid Society. A second draft was reviewed and approved by The Endocrine Society Council. At each stage of review, the Task Force received written comments and incorporated substantive changes. Conclusions: Practice guidelines are presented for diagnosis and treatment of patients with thyroid-related medical issues just before and during pregnancy and in the postpartum interval. These include evidence-based approaches to assessing the cause of the condition, treating it, and managing hypothyroidism, hyperthyroidism, gestational hyperthyroidism, thyroid autoimmunity, thyroid tumors, iodine nutrition, postpartum thyroiditis, and screening for thyroid disease. Indications and side effects of therapeutic agents used in treatment are also presented.     

Executive summary of evidence and consensus-based Clinical Practice Guidelines for management of obesity and overweight in midlife women: An AIIMS-DST initiative

Background and aimsWeight gain is an independent risk factor for decline in cardiometabolic and overall health-related quality of life in midlife women. The AIIMS-DST initiative aims to develop and validate stepwise recommendations specific for weight management in midlife women.MethodsThe key clinical questions specific to weight management in midlife women were finalised with the help of a multidisciplinary team of experts in the guideline development group (GDG). Phase I included a systematic and/or narrative review to gather evidence, grading of evidence and expert opinion was sought to develop clinical practice recommendations for each clinical question. Phase II focused on validation of clinical practice recommendations using the peer-review, Delphi method and GRADE approach.Results-The guidelines provide clinical practice points to address challenges encountered by midlife women in their attempts to manage obesity via lifestyle modification techniques. The initiation of discussion would help the healthcare provider to identify the weight management needs of the women, educate women on different modalities of weight management, and empower them to incorporate corrective lifestyle behaviours. Before initiating the management, a comprehensive assessment of clinical and lifestylerelated parameters should be completed. A personalised behavioural lifestyle modification program addressing the midlife specific barriers for optimal metabolic, musculoskeletal, and mental health should be planned. A consistent follow-up is required for maintenance of corrective eating and activity habits by addressing midlife specific barriers for sustenance of healthy weight.ConclusionThese recommendations will be useful in opportunistic screening and management of obesity in midlife women across healthcare settings.     

Executive summary of evidence and consensus-based clinical practice guideline for management of obesity and overweight in postpartum women: An AIIMS-DST initiative

IntroductionPostpartum obesity is a public health concern. There is a need to counsel women about their postpartum weight management, accounting for various barriers they face. Limited literature in the Indian context underscored the need to develop the clinical practice guideline to be used by healthcare providers in Indian healthcare settings.MethodsThe guideline was formulated by following the standardised methodology proposed by the National Health and Medical Research Council. Various steps such as identification of the patient population, assembly of the guideline development groups, identification of the key clinical questions, guideline development methods, grading the quality of evidence and recommendations and guideline translation were carried out to develop and validate the clinical practice recommendations.ResultsThe evidence and consensus-based clinical practice guideline has been developed, providing recommendations for key topics of interest for first-line treatment of obesity (lifestyle-related management). Recommendations focus on screening and initiating discussion with overweight and obese postpartum women as well as those who had normal pre-pregnancy body mass index but have retained excessive weight in the postpartum period. Recommendations highlight the evaluation and management of dietary, physical activity and breastfeeding behaviour. Recommendations also account for behavioural modification techniques to improve adherence to the prescribed weight management advice. Duration and frequency of follow-ups as well as the advice to be disseminated have also been discussed in the recommendations.ConclusionThe guideline provides clinical practice points that can be used by healthcare providers, postpartum women and policymakers for opportunistic screening and management of postpartum obesity.     

Screening for osteoporosis in men: a clinical practice guideline from the American College of Physicians

DESCRIPTION: The American College of Physicians developed this guideline to present the available evidence on risk factors and screening tests for osteoporosis in men. METHODS: Published literature on this topic was identified by using MEDLINE (1990 to July 2007). Reference mining was done on the retrieved articles, references of previous reviews, and solicited articles from experts. The inclusion criteria for the studies were measuring risk factors for low bone mineral density or osteoporotic fracture in men or comparing 2 different methods of assessment for the presence of osteoporosis in men. This guideline grades the evidence and recommendations by using the American College of Physicians' clinical practice guidelines grading system. RECOMMENDATION 1: The American College of Physicians recommends that clinicians periodically perform individualized assessment of risk factors for osteoporosis in older men (Grade: strong recommendation; moderate-quality evidence). RECOMMENDATION 2: The American College of Physicians recommends that clinicians obtain dual-energy x-ray absorptiometry for men who are at increased risk for osteoporosis and are candidates for drug therapy (Grade: strong recommendation; moderate-quality evidence). RECOMMENDATION 3: The American College of Physicians recommends further research to evaluate osteoporosis screening tests in men.     

2019 Chinese Clinical Practice Guidelines for the Prevention of Mother-to-child Transmission of Hepatitis B Virus

To develop the evidence-based guidelines for managing mother-to-child transmission of hepatitis B virus in China, a multidisciplinary guideline development group was established. Clinical questions were identified from two rounds of surveys on the concerns of first-line clinicians. We conducted a comprehensive search and review of the literature. A grading of recommendations’ assessment, development, and evaluation system was adopted to rate the quality of evidence and the strength of recommendations. Recommendations were formulated based on the evidence, overall balance of benefits and harms (at individual and population levels), patient/health worker values and preferences, resources available, cost-effectiveness, and feasibility. Eventually, recommendations related to 13 main clinical concerns were developed, covering diagnostic criteria, treatment indications, antiviral therapy choice, timing to initiate and discontinue treatment, immunoprophylaxis strategy at birth, and how to deal with special situations, such as unintended pregnancy, assisted reproduction, and breastfeeding. The guidelines are intended to serve as guidance for clinicians and patients, to optimize the management of majority of pregnant women who are positive for hepatitis B surface antigen. Guideline registration: International Practice Guide Registration Platform (IPGRP-2018CN040).     

Moxibustion for primary dysmenorrhea: A protocol for evidence-based clinical practice guideline

Background:Primary dysmenorrhea (PD) is a common gynecological disease characterized by lower abdominal pain. Moxibustion as a traditional Chinese treatment, can effectively treat PD with few adverse reactions. Nowadays, there is still no standard guideline for moxibustion treatment of PD, so related clinical practice guidelines need to be developed.Methods:This guideline will be developed in line with the latest guideline definition from Institute of Medicine, and that applies the GRADE system as well as the World Health Organization handbook to appraise the quality of evidence and develop recommendations. We will set up a Guideline working group, put forward the corresponding problems based on the principle of Population, Intervention, Comparison, Outcomes (PICO), and complete the literature retrieval. After achieving consensus through evidence syntheses and 2 to 3 rounds of Delphi process, we will also consider patients values and preferences and implement peer review in the guideline.Result:We will put forward evidence-based best practice recommendations and moxibustion standard to improve the symptoms caused by primary dysmenorrhea in a more efficient way. At present, the research is still in progress, and there is no result to report.Conclusions:This guideline will be helpful to clinical acupuncturists and other professionals to further improve clinical efficacy in treating PD with moxibustion. Moreover, we will also constantly update and evaluate the evidence to both support recommendations and identify gap areas for future research.Systematic Review registrations:registration number: IPGRP-2020CN021     

Therapeutic guidelines on ulcerative colitis: A GRADE methodology based effort of GETECCU

Background and aim

Evidence-based clinical guidelines on Ulcerative colitis (UC) have been developed through a consensus, while GRADE methodology is the current standard for guideline development. This is the first one based on GRADE methodology on UC.

Methods

Following GRADE methodology, the Spanish Group of Ulcerative Colitis and Crohn's disease (GETECCU) have developed a guideline on UC treatment. After selection of relevant clinical scenarios, 32 clinical questions were chosen and recommendations were established.

Results

In 2 questions no recommendation was possible. Twenty-two actions were recommended for, 14 strongly and 8 weakly. However, in 8 questions a recommendation against doing something was obtained, weak in 5 and strong in 3. The majority of recommendations were based on moderate quality evidence, and only 5 on high-quality evidence.

Conclusions

With GRADE methodology we find a clear recommendation on possible actions in most clinical decisions in UC treatment, but much more clinical high-quality research is needed.     

Pharmacologic treatment of low bone density or osteoporosis to prevent fractures: a clinical practice guideline from the American College of Physicians

DESCRIPTION: The American College of Physicians (ACP) developed this guideline to present the available evidence on various pharmacologic treatments to prevent fractures in men and women with low bone density or osteoporosis. METHODS: Published literature on this topic was identified by using MEDLINE (1966 to December 2006), the ACP Journal Club database, the Cochrane Central Register of Controlled Trials (no date limits), the Cochrane Database of Systematic Reviews (no date limits), Web sites of the United Kingdom National Institute of Health and Clinical Excellence (no date limits), and the United Kingdom Health Technology Assessment Program (January 1998 to December 2006). Searches were limited to English-language publications and human studies. Keywords for search included terms for osteoporosis, osteopenia, low bone density, and the drugs listed in the key questions. This guideline grades the evidence and recommendations according to the ACP's clinical practice guidelines grading system. RECOMMENDATION 1: ACP recommends that clinicians offer pharmacologic treatment to men and women who have known osteoporosis and to those who have experienced fragility fractures (Grade: strong recommendation; high-quality evidence). RECOMMENDATION 2: ACP recommends that clinicians consider pharmacologic treatment for men and women who are at risk for developing osteoporosis (Grade: weak recommendation; moderate-quality evidence). RECOMMENDATION 3: ACP recommends that clinicians choose among pharmacologic treatment options for osteoporosis in men and women on the basis of an assessment of risk and benefits in individual patients (Grade: strong recommendation; moderate-quality evidence). RECOMMENDATION 4: ACP recommends further research to evaluate treatment of osteoporosis in men and women.     

Canadian Cardiovascular Society atrial fibrillation guidelines 2010: implementing GRADE and achieving consensus

This article describes the process of the Canadian Cardiovascular Society 2010 atrial fibrillation (AF) guidelines update. Guideline development was based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system of evaluation. GRADE separates the quality of evidence (very low, low, moderate, or high quality) from the strength of recommendations (strong or conditional, ie, weak). GRADE allows acknowledgement of values and preferences in the provision of clinical care as well as costs of interventions in determining the strength of recommendations. Disclosures of relationships with industry or other potential conflicts of interest were reported at the outset and annually. Each recommendation was approved by at least a two-thirds majority of the voting panel (those with a significant conflict recusing themselves from voting on those specific recommendations).     

The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.