Clinical guidelines are an important and objective part of physicians' evidence-based practice for decision making. Carefully formulated clinical guidelines are the result of a combination of relevant research linking evidence to clinical practice(1). Clinical guidelines make the sophisticated scientific texts available to easy-to-use health care providers(2). Clinical guidelines are a systematic collection of the latest and most authoritative scientific evidence that describes the methods of clinical treatment of a patient in a categorized manner taking into account the priorities, effectiveness, and cost-effectiveness(3).
Clinical guidelines are developed to facilitate physicians' decisions about patients' medical care in specific medical situations (4, 5). In recent years, clinical guidelines have been used in world health systems to address some of the problems in the health system. Among the purposes of using clinical guidelines are the following: Providing an appropriate service model based on the best available evidence and documentation and in limited cases, general consensus, providing a basis and rational model for referring patients, reducing the differences of opinion in clinical practice, providing focus on continuing education and quality control processes including clinical auditing, focus on weaknesses in existing documentation and points that need to be focused on for future researches, advancing, and promoting efficient use of Resources, control of costly treatment and diagnostic applications, and providing evidence-based context for insurance tariffs (6, 7).
Clinical guidelines assist physicians and nurses in providing the best clinical guidance. Furthermore, changing in the process of services provided by following these guidelines will lead to cost savings; Therefore, paying attention to clinical guidelines is a predominant part of clinical governance that assists physicians and nurses in developing, following up, monitoring and improving standards (8, 9).
On the other hand, the implementation of clinical guidelines has not been easy and sometimes, it has encountered obstacles(10). According to research, clinical guidelines are not usually used. To help implement clinical guidelines, obstacles must be identified and the right strategies must be considered for their successful implementation (11–13). Among these problems and obstacles there can be; Organizational constraints, ambiguous and complex guidelines and their incompleteness, disagreement with the guidelines due to non-compliance with the executive environment and lack of sufficient evidence, knowledge, and attitude, inefficiency and previous inefficiency, lack of attention to patients' priorities and wishes, lack of the possibility of updating for use, and environmental factors, lack of time management and time constraints, etc(10).
Among the existing studies, lack of time required to use clinical guidelines and lack of knowledge and understanding about them have been introduced as the most common obstacles in the implementation of clinical guidelines(14–17).
The results of a review of the factors influencing the implementation of clinical guidelines show that the use of multiple factors is more effective than the use of a single factor to succeed in this field. In general, the factors influencing the successful implementation of clinical guidelines are: characteristics of clinical guidelines, including their fluency and comprehensibility, characteristics of specialists such as familiarity with clinical guidelines and their content, patient characteristics such as having two diseases simultaneously. Finally, environmental characteristics such as adequate attention and time of employees and the support of colleagues and supervisors in the workplace are considered as the important factors (18).
In a study conducted in China entitled "Obstacles to the implementation of clinical guidelines", the results of the study showed that the main obstacles are related to the inherent defects in the clinical guidelines themselves and the existence of defects and ambiguities in the functioning of the system. More precisely, the main obstacles were: lack of ease of use of clinical guidelines, for example, in terms of unrelatedness to the hospital information system, lack of evidence from Chinese samples (meaning to be native), usability problems such as lack of transparency and feasibility in action (19).
In other study findings, the most important obstacles to full implementation of clinical guidelines include; Lack of resources, lack of knowledge of the content of the guidelines, non-acceptance of the recommendations of the clinical guidelines and the failure of the clinical guidelines to make a clear (10).
The results of another study of barriers to the use of clinical guidelines among physicians in the Netherlands showed that Dutch general practitioners have a positive attitude towards clinical guidelines. This study reports the high level of adherence and low level of barriers among physicians. In this study, most of the perceived barriers are about the patient-related recommendations and this indicates that current guidelines do not always adequately address patients' preferences, needs, and abilities(20). The importance of patients' opinions in drafting clinical guidelines for improving treatment outcomes has been emphasized(21).
In order to pave the way for the implementation of clinical guidelines in medical centers to achieve beneficial clinical benefits for physicians and patients and to improve the quality of clinical services and to achieve the economic benefits arising from it, it is necessary to explore and categorize the influencing factors in the implementation of clinical guidelines throughout the world. The specific objectives of this review are:
1-Identifying the factors affecting and facilitating the implementation of clinical guidelines in medical centers in the world
2- Identifying the obstacles and limitations of implementing clinical guidelines in medical centers in the world