Preserving Health Beyond Infection Control: Frailty, Weight, and Cognition in OPAT Patients

<b>Background:</b> Outpatient Parenteral Antimicrobial Therapy (OPAT) is a validated alternative to inpatient care for complicated infections, ensuring clinical efficacy, safety, and cost-effectiveness. However, its impact on patient-centered outcomes such as nutritional status, frailty, and cognitive well-being has rarely been studied. <b>Methods:</b> We conducted a multicentric retrospective observational study of patients treated with OPAT between April 2024 and July 2025 in two tertiary care hospitals. Baseline demographics, comorbidities, weight, frailty status (Rockwood Clinical Frailty Scale (CFI)), and infection-related variables were collected. Follow-up assessments evaluated body weight, frailty, and subjective cognitive status. Clinical outcomes, adverse events, and hospital readmissions were recorded. <b>Results:</b> Of 139 patients treated with OPAT, 119 were included in the analysis (56% male, median age 67 years). Common comorbidities were ischemic heart disease (33%), diabetes mellitus (29%), chronic pulmonary disease (22%), and solid tumors (19%). The most frequent infections were urinary tract infections (UTIs) (29%), osteomyelitis (25%), and pneumonia (17%). Multidrug-resistant (MDR) organisms were isolated in 66% of cases. Clinical recovery occurred in 82,5% of patients, while 16% required readmission in the next 30 days; no deaths were reported. Body weight (median 73 vs. 73.0 kg at baseline, <i>p</i> = 0.43) and frailty index (median 2.5 vs. 2.4, <i>p</i> = 0.16) remained stable. Cognitive status was unchanged in 85.6%, declined in 5.9%, and improved in 8.5%. <b>Conclusions:</b> OPAT was confirmed to be clinically robust and well tolerated, with additional potential benefits in preserving weight, frailty status, and cognitive well-being. These findings suggest that OPAT not only ensures infection control but may also protect against hospitalization-related functional decline. Prospective studies incorporating standardized geriatric and cognitive assessments are needed to confirm these preliminary findings and define OPAT's broader role in holistic patient care.