Content Validity of the Lee Chronic Graft-versus-Host Disease Symptom Scale as Assessed by Cognitive Interviews

The Lee Chronic Graft-versus-Host Disease (cGVHD) Symptom Scale has been recommended for use by the 2005 and 2014 National Institutes of Health (NIH) Consensus Conferences to capture cGVHD symptoms. Although the cGVHD Symptom Scale was previously validated, this study aims to reexamine the instrument's content validity by exploring the clarity, comprehensibility, relevance, and ease of use in a contemporary cGVHD sample, toward Food and Drug Administration (FDA) qualification of this patient-reported outcomes (PRO) instrument as a drug development tool. Attaining FDA qualification means that an instrument has been judged to be a reliable and valid measure of clinical benefit. Twenty adult patients with a median age of 58 year (range, 31 to 79 years) participated. The median duration of cGVHD was 33 months (range, 0 to 134.4 months), and current NIH severity score was mild in 1 patient, moderate in 10 patients, and severe in 9 patients, with a median of 5.5 treatments (range, 0 to 14) ever used for cGVHD. The median summary score was 23 (range, 8 to 51), and the median time to complete the scale was 2 minutes, 7 seconds (range, 1 minute, 8 seconds to 4 minutes). Symptoms of cGVHD were well captured on the Lee cGVHD Symptom Scale, although 4 additional symptoms/signs were mentioned by 15% of the participants. Participants mostly reported that item wording was clear and provided accurate definitions of specific terminologies; however, 7 participants (35%) reported finding 1 or more items in the skin domain unclear, reporting, for example, that rashes and itchy skin seemed synonymous. Two of 19 participants (10.5%) described how their answers would have changed had they been asked about their symptoms within the past month instead of within the past week, owing to recently resolved symptoms. All participants were able to accurately explain the concept of "bother" in their own words and distinguish it from symptom severity or other related symptom attributes. In summary, participants found the Lee GVHD Symptom Scale to be a comprehensive and understandable way to report their cGVHD symptom experience. Future work will focus on options for the recall period, the phrasing of skin items, and whether some very rare symptoms (eg, feeding tube, use of oxygen) should continue to be a part of the scale.