Predictors for spontaneous resolution of classical FUO in patients undergoing PET-CT

Spontaneous resolution is common in patients with classic fever of unknown origin (FUO). Identifying predictors of spontaneous resolution could reduce the usage of unnecessary, invasive tests or empirical therapy, and furthermore reduce patient anxiety. Identify predictors associated with spontaneous resolution of FUO. A single center, retrospective, cohort study. All hospitalized patients who underwent an [18F] FDG PET-CT scan for the investigation of classical FUO between 1/2012 and 1/2020 were included. We compared patients with spontaneous resolution of fever and clinical symptoms, to those who were diagnosed with a specific etiology of FUO (subdivided to infectious diseases, non-infectious inflammatory diseases (NIID), and malignancies). Epidemiologic characteristics as well as laboratory and PETCT study results were compared. Variables that were found to be associated with spontaneous resolution of FUO on univariate analysis ( p