Background: Pyoderma gangrenosum (PG) is a rare autoinflammatory skin condition that causes tissue destruction and subsequent painful ulcers. Current treatment paradigms rely on outcome measure instruments which have not been well-characterized in literature.
Objectives: To systematically review 1) the outcome measure instruments used in PG clinical trials and the domains that they cover and 2) identify any associated validation studies and evaluate the measurement properties and the methodological quality.
Methods: We searched six databases and identified 20 unique outcome measure instruments for PG. We evaluated the measurement properties and methodological quality of associated instrument validation studies using the COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) checklist.
Results: In total, 6 articles were included (2 RCTs, 4 cohort studies). These articles utilized a total of 20 different outcome instruments, including 11 physician-reported instruments, 8 patient-reported instruments, and 1 composite instrument that included both physician and patient elements. Of these, 85% of the instruments lacked any validation data. Of the remaining three validated instruments, methodological quality was not available for half of the COSMIN categories.
Conclusions: 17 unvalidated outcome measure instruments have been used in clinical trials and cohort studies for PG. We conclude that more PG validation studies are required for existing instruments and new instruments may need to be developed to inform the consensus process for the core outcome set of PG.
Dr. Afsaneh Alavi, Department of Medicine (Division of Dermatology), University of Toronto, Women’s College Hospital, Toronto, ON, Canada
Dr. Alex G. Ortega-Loayza, Department of Dermatology, Oregon Health Science University, Portland, Oregon, USA
Dr. William W. Huang, Department of Dermatology, Oregon Health Science University, Portland, Oregon, USA
Disease Category: Wounds
Disease Name: Pyoderma gangrenosum
Age Range: 18 - 80
Sex: Either
Nature of Intervention: Any
- None
- Systematic review of outcome measures/measurement instruments
- Systematic review
Search strategy
Using the terms ‘pyoderma gangrenosum’ and ‘clinical trial’, or ‘randomized clinical trial’, or ‘RCT’, we searched for RCTs or clinical trials in the following databases from inception to May 27, 2019 without restrictions: MEDLINE and PubMed.
Inclusion and exclusion criteria
Eligibility for inclusion of articles was established a priori. Articles were included if: (i) they used one or more therapies for the treatment of PG; (ii) study designs were experimental or observational (RCT, case-control, cohort); and (iii) reported clear outcome measure instruments. Articles were excluded if: (i) they did not meet any of the three inclusion criteria; (ii) they were not primary literature; (iii) they were conference abstracts, and (iv) they were case series with fewer than five patients. Two authors (J.D.L. and M.M.H.) undertook study selection and both abstract screening and data extraction were performed independently. Disagreements were resolved by discussions between the two authors. All instruments were documented from included articles with respect to the range of possible values and potential domains.
Search for instrument validation data
The reference lists of included instrument articles were searched, and an internet search was also conducted for PG psychometric data. Articles were included if they contained evidence pertaining to one of COSMIN’s checklist criteria (e.g. validity, reliability, interpretability, and feasibility). The search was also limited to articles with abstracts involving at least five patients and containing original data.
Evaluating methodological quality of included studies
The COSMIN checklist was used to assess the methodological quality of the included studies. This checklist uses a four-point rating scale of ‘very good’, ‘adequate’, ‘doubtful’, or ‘inadequate’ for each measurement property and is based on the lowest rating for each item assessed. The two authors (J.D.L. and M.M.H.) independently assessed methodological quality and differences were resolved through discussions.