Quality of Life, Severity Scales Correlated in Patients With Psoriasis Worldwide

Across the globe, data on patients with psoriasis show correlations between scores on the Psoriasis Area and Severity Index (PASI) and the Dermatology Quality of Life Index (DLQI), according to study findings published in Acta Dermato-Venereologica. However, patient factors associated with scores on each scale differed across countries, indicating that treatment guidelines may need to be adapted across regions to most effectively improve quality of life.

Psoriasis, a chronic inflammatory skin disease, affects between 1% and 10% of the global population, with prevalence rates greater in high-income regions such as western Europe and North America. The introduction of biologic drugs in recent years has helped many patients achieve skin clearance and better quality of life, but access to these drugs is inconsistent globally. Previous research has established a correlation between PASI (range, 0-72; higher scores indicate more severe psoriasis) and DLQI (range, 0-30; higher scores indicate a larger effect on quality of life), but no studies have explored how PASI and DLQI interact across different geographical regions.

A dermatologist examines the skin of a patient with psoriasis | Image credit: © fusssergei - stock.adobe.com

Study investigators set out to conduct this area-specific research by analyzing data from the longitudinal, observational Global Healthcare Study on Psoriasis. Since 2020, it has yielded sociodemographic and psoriasis-related disease and treatment data from 2 dermatology centers in Switzerland, 31 in Brazil and Chile, 4 in China and Singapore, and 1 in the US. Adult patients with a diagnosis of psoriasis were included in the data set if they consented to participate.

A total of 1158 patients were included; 54.7% were men and 19.4% had concomitant psoriatic arthritis. The median (IQR) age at diagnosis was 31 (20-44) years and at the time of their visit was 48 (36-59) years. Median (IQR) PASI and DLQI scores were 6 (3-12) and 8 (4-15), respectively. The most common treatments reported in the sample were topicals (90.8%) and nonbiologic systemic therapies (66.8%); a minority of patients received phototherapy (46.4%) or biologics (41.2%).

Analysis revealed a Spearman correlation coefficient of 0.53 between DLQI and PASI, indicating a moderate correlation. The correlations were significant in all 4 geographic regions (P < .001 for Latin America, Switzerland, and Asia; P = .004 for the US). Investigators noted some covariates that differed in their relationships with the scales across regions. For instance, education had a significant negative effect on DLQI only in Switzerland. In Latin America, current age had a significant negative effect on DLQI, whereas age at diagnosis and body mass index had positive effects on that DLQI.

The relationship between PASI and DLQI appeared to be nonlinear, with greater coefficients at higher quantiles. In other words, an increase in PASI is linked to a greater increase in DLQI in patients with already high DLQI scores.

Cultural differences across regions could influence why patients with psoriasis responded differently to the DLQI, the authors noted. Varying levels of treatment access and different drug approval processes also could have affected the correlation between PASI and DLQI across countries.

Although the investigators called this the most comprehensive effort to date using the Global Healthcare Study on Psoriasis dataset to assess the relationship between psoriasis severity and quality of life globally, they noted some limitations to their study. The number of countries included per continent was low, and there were only 51 patients included from the US. The collection of data from specialized psoriasis centers may have contributed to higher PASI and DLQI values compared with the general population.

Still, their findings of a global correlation between PASI and DLQI and several patient characteristics associated with DLQI across countries could help inform the creation of treatment guidelines for psoriasis.

“The aim is to use effective treatment regimens in the future, possibly depending on geographical region, in order to improve patients’ quality of life and reduce the severity of disease globally,” the authors concluded.

Reference

Maul JT, Maul LW, Didaskalu JA, et al. Correlation between Dermatology Life Quality Index and Psoriasis Area and Severity Index in patients with psoriasis: a cross-sectional global healthcare study on psoriasis. Acta Derm Venereol. 2024;104:adv20329. doi:10.2340/actadv.v104.20329