Psoriasis is a common chronic inflammatory disease affecting a diverse patient population, yet epidemiological and clinical data related to psoriasis in patients with skin of color are sparse. The Hispanic ethnic group includes a broad range of skin types and cultures. Prevalence of psoriasis in a Hispanic population has been reported as lower than in a white population1; however, these data may be influenced by the finding that Hispanic patients are less likely to see a dermatologist when they have skin problems.2 In addition, socioeconomic disparities and cultural variations among racial/ethnic groups may contribute to differences in access to care and thresholds for seeking care,3 leading to a tendency for more severe disease in skin of color and Hispanic ethnic groups.4,5 Greater impairments in health-related quality of life have been reported in patients with skin of color and Hispanic racial/ethnic groups compared to white patients, independent of psoriasis severity.4,6 Postinflammatory pigment alteration at the sites of resolving lesions, a common clinical feature in skin of color, may contribute to the impact of psoriasis on quality of life in patients with skin of color. Psoriasis in darker skin types also can present diagnostic challenges due to overlapping features with other papulosquamous disorders and less conspicuous erythema.7
We present a post hoc analysis of the treatment of moderate to severe psoriasis with a novel fixed-combination halobetasol propionate (HP) 0.01%–tazarotene (TAZ) 0.045% lotion in a Hispanic patient population. Historically, clinical trials for psoriasis have enrolled low proportions of Hispanic patients and other patients with skin of color; in this analysis, the Hispanic population (115/418) represented 28% of the total study population and provided valuable insights.
Methods
Study Design
Two phase 3 randomized controlled trials were conducted to demonstrate the efficacy and safety of HP/TAZ lotion. Patients with a clinical diagnosis of moderate or severe localized psoriasis (N=418) were randomized to receive HP/TAZ lotion or vehicle (2:1 ratio) once daily for 8 weeks with a 4-week posttreatment follow-up.8,9 A post hoc analysis was conducted on data of the self-identified Hispanic population.
Assessments
Efficacy assessments included treatment success (at least a 2-grade improvement from baseline in the investigator global assessment [IGA] and a score of clear or almost clear) and impact on individual signs of psoriasis (at least a 2-grade improvement in erythema, plaque elevation, and scaling) at the target lesion. In addition, reduction in body surface area (BSA) was recorded, and an IGA×BSA score was calculated by multiplying IGA by BSA at each timepoint for each individual patient. A clinically meaningful improvement in disease severity (percentage of patients achieving a 75% reduction in IGA×BSA [IGA×BSA-75]) also was calculated.
Information on reported and observed adverse events (AEs) was obtained at each visit. The safety population included 112 participants (76 in the HP/TAZ group and 36 in the vehicle group).
Statistical Analysis
The statistical and analytical plan is detailed elsewhere9 and relevant to this post hoc analysis. No statistical analysis was carried out to compare data in the Hispanic population with either the overall study population or the non-Hispanic population.
Results
Overall, 115 Hispanic patients (27.5%) were enrolled (eFigure). Patients had a mean (standard deviation [SD]) age of 46.7 (13.12) years, and more than two-thirds were male (n=80, 69.6%).
eFigure. Summary of participant disposition in the 2 phase 3 studies of halobetasol propionate (HP) 0.01%–tazarotene (TAZ) 0.045% lotion (Hispanic randomized patients, pooled data, intention-to-treat population, N=115).
Overall completion rates (80.0%) for Hispanic patients were similar to those in the overall study population, though there were more discontinuations in the vehicle group. The main reasons for treatment discontinuation among Hispanic patients were participant request (n=8, 7.0%), lost to follow-up (n=8, 7.0%), and AEs (n=4, 3.5%). Hispanic patients in this study had more severe disease—18.3% (n=21) had an IGA score of 4 compared to 13.5% (n=41) of non-Hispanic patients—and more severe erythema (19.1% vs 9.6%), plaque elevation (20.0% vs 10.2%), and scaling (15.7% vs 12.9%) compared to the non-Hispanic populations (Table).
