Adherence to CAL/BDP PAD-Cream Influences Treatment Effectiveness and Preference in Scalp Psoriasis Under Real-Life Conditions: Results from the Prospective, Multicenter, Observational PRO-SCALP Study.

INTRODUCTION: Scalp psoriasis is often associated with poor adherence to topical therapy. A novel formulation of calcipotriol and betamethasone dipropionate based on polyaphron dispersion (CAL/BDP PAD-cream) showed improved outcomes and satisfaction in the PRO-SCALP study, particularly in patients with high adherence. We evaluated how adherence to CAL/BDP PAD-cream influences patients- and clinicians-reported outcomes and treatment preferences in mild-to-moderate scalp psoriasis under real-life conditions in Europe. METHODS: PRO-SCALP patients reported their adherence level using a visual analogue scale (VAS). Outcomes were compared between low- and high-adherence subgroups. RESULTS: Among 252 patients, 59.9% reported high adherence (VAS 80-100). Older patients and those with moderate disease reported high adherence (both p < 0.05). High-adherent patients reported higher scores in the Treatment Satisfaction Questionnaire for Medication Version 9, for Convenience of use (p = 0.0019) and Global Satisfaction (p = 0.0166) domains, and in the Psychosocial Effects of Scalp Psoriasis Questionnaire (p = 0.0004) at week 8. Both adherence subgroups showed significant reductions in the scalp Worst Itch Numeric Rating Scale (WI-NRS), scalp-modified Psoriasis Area and Severity Index (S-mPASI), and Scalpdex scores (all p < 0.0001 vs. baseline), although high-adherent patients achieved greater improvements in WI-NRS (p < 0.0001), S-mPASI (p = 0.0153), and the Scalpdex Symptoms domain (p = 0.001) than low-adherent. Each 10% increase in adherence corresponded to a 0.10- and 0.35-point reduction in S-mPASI and WI-NRS (both p < 0.05) at week 8. Scalp-Physician Global Assessment success rates were comparable in low- vs. high-adherence subgroups (65.0% vs. 70.5%; p = 0.3633). Sleep quality improved significantly in both subgroups (p < 0.0001). High adherence was associated with higher Patient Preference Questionnaire scores (p = 0.0012), better Cream Usability Scalp Psoriasis Questionnaire ratings (p = 0.0455) and greater product consumption (p < 0.0001), despite similar once-a-day usage. CONCLUSION: High adherence to CAL/BDP PAD-cream was associated with greater effectiveness, satisfaction, preference, and QoL. While patients with low adherence still benefited, maximizing adherence is key for optimal real-world outcomes in scalp psoriasis. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier NCT05811234.