Evaluation of prescribing practices and treatment failure for purulent skin and soft tissue infections in patients with obesity.

Objective: Evaluate prescribing practices and risk factors for treatment failure in obese patients treated for purulent cellulitis with oral antibiotics in the outpatient setting. Design: Retrospective, multicenter, observational cohort. Setting: Emergency departments, primary care, and urgent care sites throughout Michigan. Patients: Adult patients with a body mass index of ≥ 30 kg/m Methods: Obese patients receiving oral antibiotics for purulent cellulitis between February 1, 2020, and August 31, 2023, were assessed. The primary objective was to describe outpatient prescribing trends. Secondary objectives included comparing patient risk factors for treatment failure and safety outcomes between patients experiencing treatment success and those experiencing treatment failure. Results: Two hundred patients were included (Treatment success, n = 100; Treatment failure, n = 100). Patients received 11 antibiotic regimens with 26 dosing variations; 45.5% were inappropriately dosed. Sixty-seven percent of patients received MRSA-active therapy. Treatment failure was similar between those appropriately dosed (46.4%) versus under-dosed (54.4%) ( Conclusions: Nearly half of antimicrobial regimens prescribed for outpatient treatment of cellulitis in patients with obesity were suboptimally prescribed. Opportunities exist to optimize agent selection, dosing, and duration of therapy in this population.