Predictors of Failure of Empiric Outpatient Antibiotic Therapy in Emergency Department Patients With Uncomplicated Cellulitis.

Introduction: Despite several expert panel recommendations and cellulitis treatment guidelines, there are currently no clinical decision rules to assist clinicians in deciding which emergency department (ED) patients should be treated with oral antibiotics and which patients require intravenous therapy at first presentation of uncomplicated cellulitis. The objective of this prospective study is to determine potential patient risk factors associated with adult patients (>17years) presenting to the ED with a concern about a skin or soft tissue infection who fail initial antibiotic therapy for the treatment of standard cellulitis and require a change of antibiotics or admission to hospital.

Methods: This study will be a prospective study conducted in two tertiary care EDs. Patients will be excluded if they have been treated with antibiotics for the current bout of cellulitis prior to presenting to the ED, patients admitted to hospital and those patients with abscesses only. Hired research assistants (RAs) will administer a questionnaire at the initial ED visit with telephone follow-up 2 weeks later. Treatment failure will be defined as patients requiring subsequent hospitalization, initiation of intravenous antibiotics (if oral antibiotics were prescribed initially), or a change of oral antibiotics for the original cellulitis.

Results: This study will provide a detailed profile of patient risk factors associated with treatment failure of cellulitis. The results will be analyzed and used in formulating a clinical decision rule for effective treatment of cellulitis presenting to the ED. Each of the predictor variables associated (p ≤ 0.1) with failed treatment in the univariate analysis will be considered in a multivariate logistic regression model. Additionally, treatment variability among clinicians in regard to cellulitis will be evaluated and compared to treatment failures, thus providing data on successful treatment regimens.

Conclusions: Results from this research may be used to generate a clinical prediction rule to assist clinicians in effectively treating patients presenting to emergency departments with cellulitis. Understanding which patient risk factors for treatment failure will assist clinicians in determining which patients will benefit from intravenous versus oral antibiotics.

Study Overview

• Status: Completed
• Conditions: Uncomplicated Outpatient Cellulitis

• Study Type: Observational
• Enrollment (Actual): 500

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • London, Ontario, Canada, N6A5W9
      • The University of Western Ontario

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Adult patients (≥ 18 years) whose chief complaint was consistent with a skin or soft tissue infection (key words included cellulitis, abscess, infection, insect bite, ulcer, or rash) were screened for eligibility by ED staff or trained research assistants and invited to participate in this study once an emergency physician confirmed a cellulitis infection.

Description

Inclusion Criteria: Adult patients (≥ 18 years) whose chief complaint was consistent with a skin or soft tissue infection (key words included cellulitis, abscess, infection, insect bite, ulcer, or rash) were screened for eligibility by ED staff or trained research assistants and invited to participate in this study once an emergency physician confirmed a cellulitis infection.

Exclusion Criteria: Patients were excluded if they were currently taking or had been recently treated with antibiotics for the cellulitis prior to presenting to the ED, if they were admitted to hospital, had an abscess only, were cognitively impaired or did not read or speak English.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Adult patients (≥ 18 years) with uncomplicated cellulitis; Adult patients (≥ 18 years) whose chief complaint was consistent with a skin or soft tissue infection (key words included cellulitis, abscess, infection, insect bite, ulcer, or rash) were screened for eligibility by ED staff or trained research assistants and invited to participate in this study once an emergency physician confirmed a cellulitis infection.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
risk factors independently associated with failure of empiric outpatient antibiotic therapy in ED patients with uncomplicated cellulitis.	The primary objective of this study was to determine risk factors independently associated with failure of empiric outpatient antibiotic therapy in ED patients with uncomplicated cellulitis.	16 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
antibiotic prescribing practices for uncomplicated cellulitis at our institution.	Secondary objectives were to describe the antibiotic prescribing practices for uncomplicated cellulitis at our institution.	16 months

Collaborators and Investigators

• Sponsor: Lawson Health Research Institute
• Collaborators: University of Western Ontario, Canada
• Investigators: Principal Investigator: Andrew McRae, MD, FRCPC, PhD, The University of Western Ontario

Study record dates

Study Major Dates

• Study Start: June 1, 2010
• Primary Completion (Actual): December 1, 2011
• Study Completion (Actual): December 1, 2011

Study Registration Dates

• First Submitted: October 22, 2013
• First Submitted That Met QC Criteria: October 24, 2013
• First Posted (Estimate): October 30, 2013

Study Record Updates

• Last Update Posted (Estimate): October 30, 2013
• Last Update Submitted That Met QC Criteria: October 24, 2013
• Last Verified: October 1, 2013

More Information

Terms related to this study

• Keywords: Cellulitis, treatment failure, skin and soft tissue infections, risk factors.
• Additional Relevant MeSH Terms: Pathologic Processes; Infections; Inflammation; Disease Attributes; Connective Tissue Diseases; Skin Diseases, Infectious; Suppuration; Emergencies; Cellulitis
• Other Study ID Numbers: 16936e