As recommended by the current guidelines, patients with infective endocarditis (IE) on the left side of the heart — an infection of the valves most commonly caused by bacteria — are typically treated with antibiotics administered intravenously in the hospital. The results of the POET trial presented at the 2018 ESC Congress and published simultaneously in the New England Journal of Medicine show that in stable patients with IE, a switch to oral antibiotics is noninferior to continued intravenous therapy. The implementation of oral antibiotic therapy could reduce long hospital stays and the associated physical and psychological burden on the patients.

Credit: V. Summersby/Springer Nature Limited

The majority of complications associated with IE, including need for surgery and death, occur during the initial phase. After this critical phase, stable patients remain in the hospital to continue receiving intravenous antibiotics for up to 6 weeks. “We had some patients for whom this requirement was totally unacceptable and even considered it like a ‘jail-sentence’,” comments lead investigator Henning Bundgaard.

Looking into options to reduce the length of hospital stays, the investigators prescribed partial oral regimens to patients with IE and discharged them to outpatient treatment in a small pilot study. “The patients were extremely happy with this arrangement and the treatment was successful; this was the initial spark for the POET trial,” explains Bundgaard. Only few observational studies had compared the use of oral versus intravenous antibiotics for IE; therefore, this randomized, noninferiority, multicentre trial was needed to evaluate the safety and efficacy of a switch in therapy.

A total of 400 patients with IE on the left side of the heart who were receiving treatment with intravenous antibiotics were randomly assigned to continue intravenous treatment or to switch to oral antibiotics. The primary outcome — a composite of all-cause mortality, unplanned surgery, embolic events, or relapse of bacteraemia, from randomization until 6 months after completion of the antibiotic treatment — occurred in 24 patients (12.1%) of the intravenously treated group and 18 patients (9%) of the orally treated group. With a between-group difference of 3.1% (95% CI –3.4 to 9.6, P = 0.40), partial oral therapy met the noninferiority criteria for the primary outcome. The incidence of adverse effects such as allergy was similar between the groups. These findings encouraged the investigators to implement partial oral antibiotic therapy for IE in several cardiology departments in Denmark.

implementation of oral antibiotic therapy could reduce long hospital stays and the associated physical and psychological burden on the patients

Nevertheless, the trial has some limitations: only stable patients with IE on the left side of the heart caused by specific bacterial strains were enrolled in the trial, although the selected bacteria account for approximately 75% of all IE cases. “Unfortunately, there is not a strong tradition for conducting randomized trials on endocarditis,” concedes Bundgaard, “but we hope this finding will be an important new topic in the next guidelines on clinical management of endocarditis,” he concludes.