Uncovering the Differences: How DLQI and WHO-5 Scores Vary in Moderate-to-Severe Psoriasis Patients Treated with Tildrakizumab 100 mg vs. 200 mg?

: Background/Objectives: Psoriasis (PsO) is a chronic inflammatory skin disease that severely impacts patients' quality of life (QoL). Its global prevalence is about 2%, with significant regional variations. PsO manifests in the form of erythematous and scaly plaques, causing intense pruritus and discomfort and limiting daily activities. The condition often includes comorbidities such as psoriatic arthritis, cardiovascular diseases, and metabolic syndrome, further deteriorating QoL. Psychological well-being is notably affected, with high levels of depression and anxiety due to the visible lesions, leading to social stigma and isolation. QoL indexes like WHO-QoL and SF-36 assess various well-being aspects, while patient-reported outcomes (PROs) provide a comprehensive understanding of PsO's impact. However, there are no universally shared PROs in outpatient practice to fully understand the impact of the disease and associated therapies. This study aims to evaluate differences between DLQI and WHO-5 in adult patients with moderate-to-severe PsO treated with tildrakizumab 100 mg or 200 mg. Methods: The study was conducted at the University Hospital of Siena, Italy, from May 2023 to April 2024. Data from 15 patients treated with tildrakizumab 200 mg and 15 patients treated with tildrakizumab 100 mg, observed for at least 28 weeks, were recorded. Demographic data, PASI, DLQI, and WHO-5 scores were analyzed. Patients in the 100 mg group (G100) were selected to match the demographic characteristics of the 200 mg group (G200). Reduction rates of DLQI and WHO-5 were assessed at baseline values and after 4, 16, and 28 weeks. Results: Both groups experienced improvements in QoL. The group treated with 200 mg showed more pronounced and rapid reductions in DLQI and WHO-5 scores compared to the 100 mg group. WHO-5 demonstrated faster improvements in overall well-being than DLQI, indicating its greater sensitivity to changes in mental well-being and overall QoL. No differences in adverse events were observed between the two groups, with no major adverse events reported. Conclusions: In our study, WHO-5 proved more sensitive than DLQI in capturing well-being changes in PsO patients treated with tildrakizumab. However, a combined use of both WHO-5 and DLQI questionnaires should be encouraged in clinical practice. Furthermore, this study confirmed the superior QoL improvement associated with tildrakizumab 200 mg compared to 100 mg. Future research should explore the long-term impact on QoL and comparative effectiveness among other biologic therapies in diverse patient populations.