Overview
The American Academy of Dermatology clinical practice guidelines aim to compile and summarize the best available evidence to guide dermatologists in their practice of evidence-based medicine. These guidelines are seen as essential by the majority of dermatologists, who believe they increase the quality of patient care [5]. However essential these guidelines may be to dermatologists, our study found that only 36.5% of the American Academy of Dermatology published guidelines are supported by strong evidence. Furthermore, there were inconsistencies in the strength of the recommendations between the 6 guidelines, with the range of recommendations supported by strong evidence spanning from nearly 20% to 50%. The newly published 2019 guidelines actually had a lower number of recommendations supported by strong evidence compared to the guidelines published in 2016 and 2018. Based on these results, we suggest that dermatologists be mindful that not all clinical practice guidelines are based on the strongest evidence and that dermatologists should regularly review guidelines with special attention to their level of evidence.
To our knowledge, we are the first to explore the level of evidence supporting the American Academy of Dermatology guidelines to include the most recently published guidelines (2019). The results of our study further complement the paradigm demonstrated in studies of other medical specialties in which the strength of clinical practice guidelines have been examined. For example, in obstetrics and gynecology, Wright et al [11] found that only 30% of the recommendations were based on high-quality evidence. In the American College of Cardiologists and American Heart Association clinical practice guidelines, Tricoci et al [10] found that a mere 11% of the recommendations were based on high-quality evidence. Shah et al [21] found that 0% of the evidence underlying the American College of Chest Physicians clinical practice guidelines for venous thromboembolism were based on the highest quality ratings, and Poonacha et al [22] found that only 9% of the National Comprehensive Cancer Network clinical practice guidelines recommendations were based on high-quality evidence. Members of our own research team demonstrated similar results to these studies. In addition, Meyer et al [23] found that in the American College of Gastroenterology, only 15% of the guidelines were supported by high evidence.
These findings, as well as those of our own study, suggest that a greater emphasis be placed on conducting and completing good-quality randomized trials and other studies to improve the quality of evidence-based medicine in dermatology. For example, the discrepancy observed between the strength of evidence supporting the acne and melanoma guidelines highlights the need for more high-quality melanoma studies. The American Academy of Dermatology melanoma clinical practice guideline identifies several gaps in research, with one being a lack of randomized controlled trials, thus demonstrating the need for an interdisciplinary approach to increase the number of high-quality studies [24]. The Strength of Recommendation Taxonomy states that for a recommendation to receive an A rating, it needs to have one of the following: a Cochrane Review with a clear recommendation, a United States Preventive Services Task Force (USPSTF) Grade A recommendation, consistent findings from at least two good-quality randomized controlled trials or diagnostic cohort studies, validated clinical decision rule in a relevant population, or a clinical evidence rating of “Beneficial” [8]. Therefore, we recommend that further research be performed to evaluate the quality and quantity of the evidence supporting the clinical practice guidelines.
Though the American Academy of Dermatology clinical practice guideline recommendations were primarily not supported by a strong level of evidence, the recommendations (especially the acne and nonmelanoma skin cancer clinical practice guidelines) were of much higher quality than those of other fields of medicine [10,21,22]. Though significant work is still required to raise the quality and quantity of evidence in dermatology guidelines, dermatology seems poised to become a leader in the compilation of truly evidence-based clinical practice guidelines if this direction is prioritized.
The strengths of our study include the following: data extraction was completed in a duplicate and blinded fashion, following the recommendations set forth by the Cochrane Handbook of Systematic Reviews of Interventions [25]; data extraction occurred over a 3-year period to include the most recent 2019 guidelines; and the results of our study were consistent with previously published articles in numerous fields of medicine. However, our study is not without limitations. Our study evaluated only clinical practice guidelines published by the American Academy of Dermatology and therefore is not generalizable outside the field of dermatology. Additionally, our study is not generalizable toward other American Academy of Dermatology quality measures such as Appropriate Use Criteria or other published literature. As some of the guidelines were published prior to the current year, they may not accurately reflect the current levels of evidence in dermatologic literature, and therefore our study may underestimate the current research quality in dermatology. Although we evaluated the overall levels of evidence of research underpinning guideline recommendations, we did not perform risk of bias assessments on each individual study. This may be seen as a perceived limitation of this study or as an opportunity for follow-up investigations. Furthermore, it should also be noted that just because a recommendation is not underpinned by strong quality evidence does not imply that it should be omitted from clinical practice guidelines. For certain recommendations, it may be difficult or impossible to achieve strong recommendations if they are based on high-risk populations or are of a direction unlikely to receive the attention of a randomized controlled trial.