Recurrent (or episodic) fever of unknown origin (FUO) as a variant subgroup of classical FUO: A French multicentre retrospective study of 170 patients

Abstract

BackgroundRecurrent FUO (fever of unknown origin) is a rare subtype of FUO for which diagnostic procedures are ill-defined and outcome data are lacking. MethodsWe performed a retrospective multicentre study of patients with recurrent FUO between 1995 and 2018. By multivariate analysis, we identified epidemiological, clinical and prognostic variables independently associated with final diagnosis and mortality. ResultsOf 170 patients, 74 (44%) had a final diagnosis. Being ≥ 65 years of age (OR = 5.2; p < 0.001), contributory history (OR = 10.4; p < 0.001), and abnormal clinical examination (OR = 4.0; p = 0.015) independently increased the likelihood of reaching a diagnosis, whereas lymph node and/or spleen enlargement decreased it (OR = 0.2; p = 0.004). The overall prognosis was good; 58% of patients recovered (70% of those with a diagnosis). Twelve (7%) patients died; patients without a diagnosis had a fatality rate of 2%. Being ≥ 65 years of age (OR = 41.3; p < 0.001) and presence of skin signs (OR = 9.5; p = 0.005) significantly increased the risk of death. ConclusionThis study extends the known yield of recurrent FUO and highlights the importance of repeated complete clinical examinations to discover potential diagnostic clues during follow-up. Moreover, their overall prognosis is excellent.