Development and psychometric validation of the REFlective evaLuation of psoriasis Efficacy of Treatment and Severity (REFLETS) questionnaire: a common measure of plaque-type psoriasis severity and treatment efficacy for patients and clinicians

BACKGROUND: To date, there is no global consensus on the definition of the severity of psoriasis. The REFlective evaLuation of psoriasis Efficacy of Treatment and Severity (REFLETS) questionnaire has recently been developed to provide a better understanding of plaque-type psoriasis severity and treatment efficacy from both patient and clinician perspectives. OBJECTIVE: This study aimed to develop and psychometrically validate the new REFLETS questionnaire to evaluate patient and clinician perceptions of plaque-type psoriasis severity and treatment efficacy. METHODS: Two similar versions of the REFLETS questionnaire were developed following a rigorous methodology for clinicians and patients, referring to ‘the psoriasis of your patient' or to ‘your psoriasis’, respectively. An observational, longitudinal, multicentre study was conducted in France with 34 dermatologists and 430 mild to severe plaque-type psoriasis patients to finalize the questionnaire and evaluate its psychometric properties. RESULTS: Two dimensions were defined – severity and treatment efficacy – with three subdimensions within severity (impact of psoriasis, symptoms and disease course), and two individual items on joint pain. The questionnaire was well accepted by clinicians and patients. Excellent internal consistency (Cronbach's alpha = 0.66–0.98) and test–retest reliability (intraclass correlation coefficients = 0.83–0.94) were demonstrated. REFLETS scores were moderately to highly correlated to Psoriasis Area and Severity Index (r = 0.35–0.70), Skindex-29 (r = 0.46–0.82) and DLQI scores (r = 0.36–0.82). Patients with decreased psoriasis severity and those with increased treatment efficacy, according to patient global evaluations, had lower severity and higher treatment efficacy REFLETS scores, respectively. CONCLUSION: REFlective evaLuation of psoriasis Efficacy of Treatment and Severity is a promising tool for assessing plaque-type psoriasis severity and treatment efficacy from patient and clinician perspectives. It may help to improve patient and clinician communication in treatment decision making.