Factors associated with delayed diagnosis of infective endocarditis: A retrospective cohort study in a teaching hospital in Japan

Patients with infective endocarditis (IE), have high mortality and morbidity, however, its early diagnosis is difficult. Few studies have examined the delayed diagnosis of IE. We aimed to investigate the factors associated with the diagnostic delay of IE. A retrospective cohort study was conducted for consecutive patients diagnosed with IE in an acute care teaching hospital in Japan from April 2006 to March 2018. Time-to-diagnosis was analyzed using a multivariate Cox hazard model for determining factors associated with days required for IE diagnosis. Factors analyzed in the model included age, gender, activities of daily living, Charlson comorbidity index, presence of internal device, chief complaint, inappropriate antibiotics use, shaking chill, fever >38°C, hypoxemia, serum C-reactive protein (CRP) < 10 mg/dL, Staphylococcus aureus as causative pathogen, findings on first echocardiography, resident as a first contact physician, primary care physician as a first contact doctor, and transport measures to the clinic/hospital. There were 145 IE patients with a mean age of 70 years and 90 were male (62.1%). The median time to the diagnosis of definite IE was 13 days and median time to consider the diagnosis of IE from first clinic/hospital visit was 6 days. The time to consider IE diagnosis was significantly delayed in patients who had inappropriate prior antibiotic use (hazard ratio [HR], 1.61; 95% confidence interval [CI], 1.01 to 2.57; P = .045), in patients without fever >38°C (HR, 1.80; 95% CI, 1.11 to 2.90; P = .016), in patients with serum CRP level < 10 mg/dL (HR, 1.53; 95% CI, 1.01 to 2.33; P = .046), and in patients who did not use an ambulance for hospital arrival (HR, 3.18; 95% CI, 1.72 to 5.85; P < .001). Delay in considering IE diagnosis is associated with inappropriate prior antibiotics use, absence of high fever, absence of high CRP level, and use of a hospital arrival vehicle other than an ambulance. For earlier IE diagnosis, inappropriate use of antibiotics should be avoided and IE should not be excluded by relatively low level of temperature or serum CRP.