Safety and clinical outcomes of outpatient parenteral antibiotic therapy for infective endocarditis in Christchurch, New Zealand: A retrospective cohort study

Objectives: We examined the safety and clinical outcomes of outpatient parenteral antibiotic therapy (OPAT) for patients with infective endocarditis (IE) in Christchurch, New Zealand.

Methods: Demographic and clinical data were collected from all adult patients treated for IE over 5 years. Outcomes were stratified by receipt of at least partial OPAT vs entirely hospital-based parenteral therapy.

Results: There were 172 episodes of IE between 2014 and 2018. OPAT was administered in 115 cases (67%) for a median of 27 days after a median of 12 days of inpatient treatment. In the OPAT cohort, viridans group streptococci were the commonest causative pathogens (35%) followed by Staphylococcus aureus (25%) and Enterococcus faecalis (11%). There were six (5%) antibiotic-related adverse events and 26 (23%) readmissions in the OPAT treatment group. Mortality in OPAT patients was 6% (7/115) at 6 months and 10% (11/114) at 1 year and for patients receiving wholly inpatient parenteral therapy was 56% (31/56) and 58% (33/56), respectively. Three patients (3%) in the OPAT group had a relapse of IE during the 1-year follow-up period.

Conclusion: OPAT can be used safely in patients with IE, even in selected cases with complicated or difficult-to-treat infections.