Core Outcome Measures in Effectiveness Trials

Treatment Failure Definitions for Non-Purulent Skin and Soft Tissue Infections: A Systematic Review

General Information

For studies involving non-purulent SSTIs, an important outcome is antimicrobial treatment failure. There is currently no uniform definition of antimicrobial treatment failure for non-purulent SSTIs. A recent systematic review identified 19 randomized controlled trials with treatment failure rates ranging from 6 to 37%. The authors speculated this variability might be due to difficulty with diagnosis due to cellulitis mimics. However, it is likely that the significant variability in treatment failure rates may be related to the lack of a uniform definition for antimicrobial treatment failure. Importantly, the majority of trials included in this systematic review assessed treatment response anywhere from 7 to 45 days after therapy had been completed. The United States Food and Drug Administration (FDA) recommends that clinical response to therapy as a primary outcome should be assessed at 48 to 72 hours after initiation of therapy. For the clinician, it is more clinically meaningful if the outcome of treatment failure is assessed during and at the end of therapy.

Given the lack of a widely accepted uniform definition, we performed a systematic review of the literature to identify studies that described antimicrobial treatment failure as a primary or secondary outcome. The primary aim of this review was to describe the common components used in definitions of antimicrobial treatment failure for adults with non-purulent SSTIs treated as inpatients, outpatients or in the ED. Identifying these components in the literature is an important first step toward establishing clear criteria to define antimicrobial treatment failure for non-purulent SSTIs.

Principal investigator: Krishan Yadav

Further Study Information

Current Stage:
October 2018 - April 2019
Funding source(s):

Health Area

Disease Category

Disease Name
Skin and soft tissue infections

Target Population

Age Range
18 - 100


Nature / type of Intervention


Systematic review

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Details of the protocol for this systematic review were registered on PROSPERO and can be accessed at:

The electronic search strategy was peer-reviewed by a second health sciences librarian in accordance with the Peer Review of Electronic Search Strategies (PRESS). We searched five electronic databases. Two independent reviewers identified studies involving adults (age >=18 years) with non-purulent SSTIs in which antimicrobial treatment failure was an outcome. There were no language restrictions. Only randomized trials or observational studies were included.

Stakeholders Involved


Study Type


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