Clinical predictors of outcome in patients with infective endocarditis receiving outpatient parenteral antibiotic therapy (OPAT).

Abstract

OBJECTIVES: Outpatient parenteral antimicrobial therapy (OPAT) is increasingly used to treat infective endocarditis (IE) with documented success. This study aims to identify risk factors for treatment failure and poor outcomes in patients with IE treated through OPAT. METHODS: We conducted a retrospective analysis of all episodes of IE treated over 13 years (September 2006 - September 2019) at a large teaching hospital in Sheffield, UK. We defined OPAT failure as unplanned readmission or death within 30 days of discharge from the OPAT service. Major adverse cardiac events (MACE) were defined as a composite of IE-related death, cardiac surgery, and recurrence of IE within the first year of completion of OPAT. RESULTS: Overall, 168 episodes of IE were reviewed. OPAT failure and MACE occurred in 44 episodes (26.2%) and 29 episodes (17.3%) respectively. On multivariable analysis, pre-existing renal failure (adjusted odds ratio [aOR], 3.00; 95% confidence interval [CI], 1.08-8.30; P = 0.034) and Charlson comorbidity score (aOR, 1.29 per unit increase; 95% CI, 1.06-1.57; P = 0.011) were associated with increased risk of failure. Previous endocarditis (aOR, 3.60; 95% CI, 1.49-8.70; P = 0.004) and cardiac complications (aOR, 3.85; 95% CI, 1.49-9.93; P = 0.005) were risk factors for MACE, whereas cardiac surgery during the initial hospitalisation for IE (aOR, 0.34; 95% CI, 0.12-0.22; P <0.001) was a protective factor. CONCLUSIONS: Our findings suggest that OPAT is safe and effective for completing antibiotic treatment for IE, including cases deemed to be at increased risk of complications. However, careful patient selection and monitoring of patients with pre-existing comorbidities and cardiac complications are recommended to optimise clinical outcomes.