Levels of evidence supporting clinical practice guidelines on invasive aspergillosis

Invasive aspergillosis (IA) is a severe life-threatening infection with challenges in therapy. The aim was to evaluate the level of evidence (LOE) supporting recommendations in clinical practice guidelines (CPGs) of IA and changes over time. Search on CPG on IA released between 2000 and 2019 was done. Last versions were evaluated and compared with previous versions. Recommendations were classified by LOE as A (multiple randomized controlled trial (RCT) or meta-analysis), B (data from a single RCT or observational studies), or C (observational studies with limitations, case series, or expert opinion). Diagnosis recommendations were excluded. Five CPG from three groups of scientific societies were identified: the 2016 Infectious Diseases Society of America/American Thoracic Society (IDSA/ATS), 2017 European Society of Clinical Microbiology Infectious Diseases/European Confederation of Medical Mycology/European Respiratory Society (ESCMID/ECMM/ERS), 2018 Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) CPGs, and their previous versions (2008 IDSA/ATS and 2011 GEMICOMED/SEIMC). ECMID/ECMM/ERS have not published any previous version. From 511 recommendations analyzed, 80 were classified as LOE A (15.7%), 223 LOE B (43.6%), and 208 LOE C (40.7%). Among 238 strong recommendations, only 57 (24.0%) were supported by LOE A. When comparing recent CPGs with previous versions, the proportion of recommendations supported by LOE A did not significantly increase over time (IDSA/ATS: 13.3% [2016] vs. 14.8% [2008], p = 0.798; and SEIMC: 22.6% [2018] vs. 19% [2011], p = 0.568). In conclusion, IA is a condition with an urgent unmet clinical need for more high-quality randomized trials.