The role of early defervescence in ruling out infective endocarditis: a cohort study

To evaluate the role of defervescence within 4 days from antibiotic treatment initiation in ruling out infective endocarditis (IE) among patients suspected of such diagnosis.

This study was conducted at the Lausanne University Hospital, Switzerland (January 2014 to May 2022). All patients with suspected IE being febrile upon presentation were included. IE was classified according to the modified Duke criteria proposed by the 2015 European Society of Cardiology guidelines, before or after applying the criterion 'resolution of symptoms suggesting IE within 4 days of the introduction of antibiotic therapy' based solely on early defervescence.

Among 1022 episodes with suspected IE, 332 (37%) had IE according to Endocarditis-Team evaluation; 248 were classified by clinical Duke criteria as definite and 84 as possible IE. The rate of defervescence within 4 days from antibiotic treatment initiation was similar (p 0.547) among episodes without (606/690; 88%) and those with IE (287/332; 86%); among episodes classified as definite and possible IE by clinical Duke criteria, 211 of 248 (85%) and 76 of 84 (90%), respectively, defervesced within 4 days from antibiotic treatment initiation. By using early defervescence as a rejection criterion, the 76 episodes with final IE diagnosis classified as possible by clinical criteria could be reclassified as rejected.

The majority of IE episodes defervesced within 4 days from antibiotic treatment initiation; thus, early defervescence should not be used to rule out the diagnosis of IE.