Identification of Patient Characteristics Associated with Rapid Clinical Response in Hospitalized Patients with Skin and Soft Tissue Infections (SSTIs)

Background: Patients with moderate-to-severe SSTIs frequently require hospitalization for intravenous (IV) antibiotic therapy. The approval of once-weekly IV antibiotics (dalbavancin and oritavancin) offer convenient treatment options that could be administered in the emergency department or infusion center. However, limited data is available describing the appropriate patient population that could benefit from outpatient once-weekly antibiotic therapy as a mechanism to avoid hospitalization. The objective of this study was to determine patient characteristics associated with rapid clinical response (defined as hospitalization ≤3 day) in patients with SSTIs.

Methods: This single center, retrospective cohort study included patients admitted to the University of Michigan Health System with SSTI from July 2012 to June 2013. Multivariate logistic regression was utilized to evaluate factors associated with rapid clinical response. Clinical outcomes were evaluated, including mortality, length of stay, recurrent SSTI within 30 days of discharge, and need for antibiotic escalation.

Results: 772 patients were evaluated and 259 patients were included. 151 (58%) patients had a length of stay ≤ 3 days. Variables associated with shorter length of stay via bivariate analysis include; age, HIV/AIDs, nonpurulent SSTI. Characteristics associated with prolonged length of stay by bivariate analysis include: chronic kidney disease, acute lower extremity edema, intensive care unit admission, ulceration or purulent discharge on physical exam, higher white blood cell count, lower glomerular filtration rate, positive wound culture, higher respiratory rate, lower diastolic blood pressure, sepsis, and classification as complex skin/soft tissue infection. Multivariate analysis to predict rapid clinical response yielded the following variables: age < 55 years, nonpurulent SSTI, and c-reactive protein (CRP) < 5 mg/dL.

Conclusion: Age <55 years old, CRP <5 mg/dL and nonpurulent SSTI were factors associated with rapid clinical response in patients requiring hospitalization for SSTIs, which may benefit from treatment with once-weekly IV antibiotic therapy as a mechanism to avoid hospitalization.