A qualitative investigation of the relevance of skin irritation and self-confidence bolt-ons and their conceptual overlap with the EQ-5D in patients with psoriasis.

OBJECTIVES: A number of bolt-ons have been proposed for the EQ-5D, including two psoriasis-specific bolt-ons, skin irritation and self-confidence. The study investigates and compares the relevance and comprehensiveness of these psoriasis-specific bolt-ons and the EQ-5D-5L and explores the potential conceptual overlaps between the existing five dimensions and the two bolt-ons. METHODS: Psoriasis patients were purposively sampled according to age and gender. Semi-structured interviews, where participants were asked to complete the EQ-5D-5L and the bolt-ons while thinking aloud, were conducted. Probes were used to investigate the thought processes of patients regarding the dimensions, wording, recall period and relevant concepts not captured by the EQ-5D-5L and bolt-ons. Data were analysed thematically. A focus group was used to confirm the findings. RESULTS: Overall, 16 patients completed the interviews. Sixteen and fifteen patients considered skin irritation and self-confidence relevant areas to describe psoriasis problems. Three patients considered itching a form of discomfort, and thus, pointed out a potential overlap between pain/discomfort and skin irritation. Twelve patients reported overall 10 general health- or psoriasis-related concepts that are not captured by the EQ-5D-5L, including itching, social relationships and sex life. Eleven patients reported that the recall period of the EQ-5D-5L might be subject to bias because of the daily or within-day fluctuations of their symptoms. CONCLUSIONS: The skin irritation and self-confidence bolt-ons contribute to improve content validity of the EQ-5D-5L in patients with psoriasis. The qualitative approach taken in this study expands the existing methodological framework for the development and testing validity of bolt-ons for the EQ-5D.

[Assessment of health-related quality of life in psoriasis patients in Hungary]. / Psoriasisban szenvedo betegek életminoségének vizsgálata Magyarországon.

INTRODUCTION: The health status and health-related quality of life (HRQoL) of patients with psoriasis in Hungary are understudied. AIM: To assess HRQoL in psoriasis patients, to compare HRQoL of psoriasis patients to that of the general public in Hungary and to identify predictors of HRQoL. METHOD: Between 2012 and 2016, two cross-sectional surveys were carried out among psoriasis patients at two academic dermatology departments. HRQoL was assessed by EQ-5D-3L, EQ Visual Analogue Scale (EQ VAS) and Dermatology Life Quality Index (DLQI). Predictors of HRQoL were analysed by multivariate linear regression. RESULTS: 434 patients were enrolled (mean age 49 years, 65% male, 81% moderate-to-severe psoriasis, 43% treated with biologics). Mean EQ-5D-3L, EQ VAS and DLQI scores were 0.74 ± 0.28, 69.06 ± 20.98 and 6.78 ± 7.38, respectively. Overall, 54%, 43%, 40%, 32% and 15% of patients indicated at least some problems in pain/discomfort, anxiety/depression, mobility, usual activities and self-care. EQ-5D-3L index scores in patients were lower compared to the age- and gender-matched general population in Hungary. The difference was statistically significant for the age groups 25-34 and 45-64 in males, and 18-64 in females (p<0.05). Female gender (p = 0.042), psoriatic arthritis (p<0.001) and palmoplantar psoriasis (p = 0.031) were associated with lower EQ-5D-3L index scores. On the contrary, employed and highly educated patients reported higher EQ-5D-3L index scores (p<0.001). CONCLUSIONS: We were the first to assess HRQoL in psoriasis patients by using EQ-5D questionnaire in Hungary, and more broadly in Central and Eastern Europe. Our findings are useful for cost-effectiveness modelling of psoriasis treatments and decision-making in healthcare. Orv Hetil. 2018; 159(21): 837-846.

Measurement properties of the EQ-5D-5L compared to the EQ-5D-3L in psoriasis patients.

The purpose of this study is to assess the measurement properties of EQ-5D-5L compared to EQ-5D-3L in psoriasis patients. METHODS: A cross-sectional survey was carried out at an academic dermatology clinic in Hungary. Psoriasis patients completed the EQ-5D-3L, EQ-5D-5L and Dermatology Life Quality Index (DLQI) questionnaires, and Psoriasis Area and Severity Index (PASI) was assessed. The UK value sets were used to calculate the 3L and 5L index scores. We tested the feasibility, ceiling effect, redistribution properties, the level of inconsistency and informativity (Shannon and Shannon Evenness indices). Spearman's rank-order correlations were performed between EQ-5D, EQ VAS, DLQI and PASI scores. Known-groups validity was evaluated by comparing age groups, clinical subtypes and treatment groups. RESULTS: Mean age of the 238 patients was 47 years, and 36.6% of them received biological therapy. Mean EQ-5D index score was 0.77 (SD: 0.26) with the 3L and 0.84 (SD: 0.19) with the 5L. The overall ceiling effect decreased from 37.1 (3L) to 32.9% (5L). Shannon index improved significantly for most dimensions, but Shannon Evenness index improved only in three dimensions. Compared to the 3L, the 5L version confirmed a better convergent validity with PASI, but not with the DLQI. Known-groups validity was equally demonstrated both for the 5L and 3L. CONCLUSIONS: The EQ-5D-5L seems to improve measurement properties by reducing ceiling effects, strengthening correlations with PASI and improving informativity. Follow-up studies are needed to test responsiveness and reliability in psoriasis.

Discrepancies between the Dermatology Life Quality Index and utility scores.

OBJECTIVE: In many jurisdictions, deterioration in quality of life assessed with Dermatology Life Quality Index (DLQI) is used for medical and reimbursement decisions in various dermatological conditions such as psoriasis. However, utility values for health states defined by the DLQI have not yet been evaluated. Therefore, we aim to estimate utilities for different health states described by the ten items of the DLQI. METHODS: A cross-sectional survey was performed in a convenience sample of the general population. Seven DLQI health states with total scores of 6, 11 and 16 (3-3 and 1 states, respectively) were developed. All of them were different from each other in the number of affected items and severity levels of impairment. The 10-year time trade-off method was used to value health states. RESULTS: Mean utilities elicited by the respondents (n = 308) for the three 6-, three 11- and one 16-point DLQI health states were 0.62-0.75, 0.59-0.66, and 0.56, respectively. In half of the six pairwise comparisons, where health states with the same total DLQI score were compared, significant difference between utilities was found. In eight out of the 15 comparisons between health states with different DLQI scores, utilities were not significantly different. CONCLUSIONS: Utility values for health states with identical DLQI total score may significantly vary. This result might be generalisable to various patient populations, in which the DLQI is used; nevertheless, further research is needed. The discrepancies between DLQI scores and utilities might have an impact on medical and reimbursement decisions as they make the utility gain from treatment uncertain.

Is the DLQI appropriate for medical decision-making in psoriasis patients?

Dermatology Life Quality Index (DLQI) is the most commonly applied measure of health-related quality of life (HRQoL) in psoriasis patients. It is among defining criteria of moderate-to-severe psoriasis and present in treatment guidelines. Our objective was to estimate preference-based HRQoL values (i.e., utilities) for hypothetical health states described by the 10 items of the DLQI in psoriasis patients. Moreover, we compare results to findings of a similar study previously conducted among the general public. A cross-sectional survey was carried out among 238 psoriasis patients. Seven hypothetical DLQI-defined health states with total scores of 6, 11, and 16 (3-3 and 1 states, respectively) were evaluated by time trade-off method. The difference in DLQI scores between hypothetical health states was set at 5 points, as it exceeds the minimal clinically important difference (MCID). Utility scores were found to be homogenous across the seven hypothetical health states (range of means for the 6-point states 0.85-0.91, range of means for the 11-point states 0.83-0.85, and mean of 0.84 for the 16-point state). Overall, mean utilities assessed by psoriasis patients were higher for all seven states compared with the general public (mean difference 0.16-0.28; p < 0.001). In 11 out of the 15 comparisons between health states with DLQI scores differing larger than the MCID, there was no statistically significant difference in utility. Thus, in clinical settings, patients with DLQI scores differing more than the MCID may have identical HRQoL. Improving the definition of moderate-to-severe disease and reconsideration of the DLQI in clinical assessment of psoriasis patients are suggested.