Using qualitative methods to establish the clinically meaningful threshold for treatment success in alopecia areata

Traditionally, appropriate anchors are used to investigate the amount of change on a clinician-reported outcome assessment that is meaningful to individual patients. However, novel qualitative methods involving input from disease state experts together with patients may better inform the individual improvement threshold for demonstrating the clinical benefit of new treatments. This study aimed to establish a clinically meaningful threshold for treatment success for the clinician-reported Severity of Alopecia Tool (SALT) score for patients with alopecia areata (AA).

A purposive sample of 10 dermatologists expert in AA and 30 adult and adolescent patients with AA and a history of ≥ 50% scalp hair loss were recruited. Semi-structured interview questions explored the outcome that represented treatment success to clinicians and patients. Findings were analyzed using thematic methods to identify treatment success thresholds.

Both informant groups confirmed scalp hair amount as the outcome of priority. Most expert clinicians considered a static threshold of 80% (n = 5) or 75% (n = 3) of the scalp hair as a treatment success. Most patient responses ranged from 70 to 90% (median: 80% of the scalp hair). Subsequently, queried patients confirmed that achieving SALT score ≤ 20 with treatment would be a success, as reflected in the Alopecia Areata Investigator Global Assessment (AA-IGA™). The novel qualitative processes used to inform this meaningful threshold reflects a clinician-then-patient process for: (a) confirmation of the patient outcome of priority; and (b) clinician input on a preliminary treatment success level for independent understanding among patients.

This qualitative investigation of expert clinicians-then-patients with AA confirmed that achieving an amount of 80% or more scalp hair (SALT score ≤ 20) was an appropriate individual treatment success threshold indicating clinically meaningful improvement for patients with ≥ 50% scalp hair loss. A qualitative investigation of a quantifiable treatment success threshold is possible through a well-designed interview process with expert clinicians and the appropriate patient population.