The Clinician Erythema Assessment (CEA) grading scale has been deemed an effective way to assess facial erythema of rosacea by Canadian and American dermatologists.
The reliability of the assessment scale has never been evaluated previously. The objective of this study was to evaluate the inter-rater and intra-rater reliability of the CEA. The findings were published in The Journal of the American Academy ofDermatology (Oct. 2014; 71(4):760–763).
“Currently, there is only one Food and Drug Administration-approved pharmacologic treatment that directly targets erythema of rosacea, leaving a potential unmet need among patients with rosacea,” stated the authors in the study. “The development of clinical therapies necessitates reliable, responsive, discriminatory, and validated outcome measure to standardize diagnosis, evaluation, and treatment.”
Twelve U.S. board-certified dermatologists participated in the study to rate 28 patients with facial erythema. Of these, three were male and 25 female, between the ages of 18 and 61 years and were all Caucasian with Fitzpatrick skin phototype ranging from I to III.
The dermatologists all under wen ta consensus training program before evaluating the patients. They were provided with reference photographs on the use of the CEA and discussed the results of the evaluations to achieve consensus. During the rating process, each dermatologist evaluated each subject twice with at least a two-hour interval between evaluation sessions. The inter-rater reliability for session one was a weighted κ of 0.74 and for session one and session twowas 0. 673. This, according to the Landis and Koch score, is considered a fair to good reproducibility where perfect is 1.0. For intra-rater reliability, the overall weighted κ statistic between session one and session two was 0.692, reported the investigators in their study.
High level of reliability reassuring
“The level of intra-rater reliability was previously unknown. This is an important concept of any measurement scale as it determines how well othe rraters achieve the same outcome,” stated
Dr. Jerry Tan, a Windsor, Ont.-based dermatologist and the study’s lead author, in an e-mail to THE CHRONICLE OF SKIN & ALLERGY.
“The high inter-rater reliability found in this study for the CEA was reassuring—demonstrating that different raters could consistently grade severity of redness.”
Dr. Tan said the scale is simple to use with its five grades—clear, almost clear, mild, moderate, and severe—that have a descriptive text to match each grade. The clinician needs to match the grade of erythema that most closely resembles that of the patient. He said the scale is also easy to teach because of the descriptions and the visual guides. “Accurate andreliable means to evaluate skin redness is critical indetermining the effect of medications and/or procedures on redness of various skin conditions,” said Dr. Tan regarding the clinical importance of an effective grading scale. A limitation of the study noted by the researchers was that all the raters were all experienced dermatologists who were trained. Dr. Tan said other dermatologists and general physicians would likely yield the same reliability if they have been trained to use the tool.
Another limitation of the study was the short time interval of two hours between ratings, which according to the authors could lead to recall bias because clinicians may have been able to remember previous scores.
As well, using photographs for the training can be problematic because photos can distort light reflection, colour and depth. However, the investigators added that it was necessary
to use them for convenience in the training module.
One more severity level needed
While the authors concluded that they support the CEA as a tool for evaluating facial erythema in rosacea, Dr. Tan noted that he might propose two changes to the scale and training: “An added grade of very severe may have been useful to ensure that the entire spectrum of redness was represented. More images of redness in people with different skin colour may be useful in the future.”