Antibiotic therapy for endocarditis in outpatient setting: is it ineffective and safe in low risk patients?

Introduction Endocarditis remains a challenging condition requiring prolonged treatment. Outpatient antibiotic therapy (OAT), including parenteral (OPAT) or oral (OOAT) regimens, has emerged as a safe, cost-effective alternative to hospital-based antibiotic therapy (HBAT) for low-risk patients. However, the lack of standardized criteria and safety concerns complicates patient selection for OAT. Objective To compare OAT and HBAT patients regarding baseline characteristics, mortality over 2 years (primary outcome), and secondary outcomes such as causes of death, re-hospitalization, and re-operation. Methods This retrospective study (2020–2024) included 36 patients diagnosed with endocarditis, divided into OAT (n=20) and HBAT (n=16) groups. Baseline characteristics, comorbidities, and outcomes were analyzed. Data were presented as frequencies and percentages or means and standard deviations. Logistic regression was used, with p<0.05 considered significant. Results The mean age was 58±16 years, and 67% of patients were male. Among OAT patients, 75% received OPAT and 25% OOAT. Comorbidities included heart failure (10%), hypertension (55%), diabetes (45%), obesity (15%), HIV infection (10%), intravenous drug use (15%), and cancer (25%). No significant differences were observed between groups in comorbidities, infection site, valvular surgery, complications, or cardiovascular device presence. Mortality rates during the follow-up (19.8±16.8 months) were comparable (HBAT: 44% vs. OAT: 15%, p=0.829), with no significant differences in first-year mortality. However, OAT significantly reduced re-hospitalization rates (HBAT: 50% vs. OAT: 15%, p=0.023) and showed differing causes of death, though re-operation rates were similar. Conclusion When guided by appropriate clinical judgment, OAT is as effective as HBAT in terms of mortality while reducing hospital burden and re hospitalization rates. OAT represents a viable option for select endocarditis patients, emphasizing the need for standardized patient selection criteria.