Comparing the psychometric properties of the EQ-5D-3L and EQ-5D-5L descriptive systems and utilities in atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a common chronic inflammatory skin disorder affecting up to 10% of adults. The EQ-5D is the most commonly used generic preference-accompanied measure to generate quality-adjusted life years (QALYs) for economic evaluations.

OBJECTIVES

We aimed to compare psychometric properties of the three-level and five-level EQ-5D (EQ-5D-3L and EQ-5D-5L) in adult patients with AD.

METHODS

In a multicentre cross-sectional study, 218 AD patients with a broad range of severity completed the EQ-5D-3L, EQ-5D-5L, Dermatology Life Quality Index (DLQI) and Skindex-16. Disease severity outcomes included the Investigator Global Assessment, Eczema Area and Severity Index and the objective SCORing Atopic Dermatitis.

RESULTS

A good agreement was established between the two EQ-5D versions with an intraclass correlation coefficient of 0.815 (95% CI 0.758-0.859, p < 0.001). Overall, 33 different health state profiles occurred in the EQ-5D-3L and 84 in the EQ-5D-5L. Compared to the EQ-5D-3L, ceiling effect was reduced for the mobility, self-care, usual activities and pain/discomfort dimensions by 4.6-11.5%. EQ-5D-5L showed higher average relative informativity (Shannon's evenness index: 0.64 vs. 0.59). EQ-5D-5L demonstrated better convergent validity with EQ VAS, DLQI and Skindex-16. The two measures were similar in distinguishing between groups of patients based on disease severity and skin-specific quality of life with a moderate or large effect size (η² = 0.083-0.489).

CONCLUSION

Both instruments exhibited good psychometric properties in AD; however, the EQ-5D-5L was superior in terms of ceiling effects, informativity and convergent validity. We recommend the use of the EQ-5D-5L to measure health outcomes in clinical settings and for QALY calculations in AD.

Health state utility values derived from EQ-5D in psoriatic patients: a systematic review and meta-analysis

BACKGROUND

To determine pooled EQ-5D utility scores for psoriasis as a general condition, plaque psoriasis, and psoriatic arthritis.

METHODS

A systematic review and meta-analysis of EQ-5D utility scores for psoriatic patients was conducted. Univariate meta-regression was used to explore the degree of heterogeneity.

RESULTS

Seventy-five studies were included in the systematic review. The EQ-5D in psoriatic patients demonstrated decent convergent, known-groups validity, and a degree of responsiveness with a ceiling effect. Among the five EQ-5D dimensions, 'self-care' showed the lowest and 'pain/discomfort' showed the highest percentages of reporting any problems. For meta-analysis, we identified 70 utility scores from 59 studies: 22 for plaque psoriasis, 26 for psoriasis as a general condition, and 22 for psoriatic arthritis. The mean (95% CIs; I²) of the EQ-5D utility scores for psoriasis as a general condition, plaque psoriasis, and psoriatic arthritis was 0.748 (0.718, 0.777; 98.8%), 0.755 (0.727, 0.783; 98.6%), and 0.585 (0.538, 0.632; 98.2%), respectively. For psoriasis as a general condition and plaque psoriasis, factors such as country, psoriasis area and severity index (PASI), dermatology life quality index (DLQI) and questionnaire version (EQ-5D-3L or EQ-5D-5L) all significantly influenced the utility scores.

CONCLUSION

Psoriasis imposes a substantial impairment on patients' quality of life, especially the pain/discomfort dimension. Heterogeneity exists among different EQ-5D utility values found in the literature.

Developing a preference-based utility scoring algorithm for the Psoriasis Area Severity Index (PASI)

Introduction: It is challenging to identify health state utilities associated with psoriasis because generic preference-based measures may not capture the impact of dermatological symptoms. The Psoriasis Area Severity Index (PASI) is one of the most commonly used psoriasis rating scales in clinical trials. The purpose of this study was to develop a utility scoring algorithm for the PASI. Methods: Forty health states were developed based on PASI scores of 40 clinical trial patients. Health states were valued in time trade-off interviews with UK general population participants. Regression models were conducted to crosswalk from PASI scores to utilities (e.g. OLS linear, random effects, mean, robust, spline, quadratic). Results: A total of 245 participants completed utility interviews (51.4% female; mean age = 45.3 years). Models predicting utility based on the four PASI location scores (head, upper limbs, trunk, lower limbs) had better fit/accuracy (e.g. R², mean absolute error [MAE]) than models using the PASI total score. Head/upper limb scores were more strongly associated with utility than trunk/lower limb. The recommended model is the OLS linear model based on the four PASI location scores (R² = 0.13; MAE = 0.03). An alternative is recommended for situations when it is necessary to estimate utility based on the PASI total score. Conclusions: The derived scoring algorithm may be used to estimate utilities based on PASI scores of any treatment group with psoriasis. Because the PASI is commonly used in psoriasis clinical trials, this scoring algorithm greatly expands options for quantifying treatment outcomes in cost-effectiveness analyses of psoriasis therapies. Results indicate that psoriasis of the head/upper limbs could be more important than trunk/lower limbs, suggesting reconsideration of the standard PASI scoring approach.

Estimation of Health Utilities Based on the Response to Treatment in Atopic Dermatitis: a Population-based Study

PURPOSE

This study estimated utility weights based on the response to treatment for atopic dermatitis in the general population.

METHODS

The Korean general population aged 20-60 years was stratified by using a random sampling method based on age and sex. Two hypothetical health states of atopic dermatitis were developed: response to treatment and no response to treatment. Health utility values were estimated by using time trade-off (TTO) based on a period of 10 years, TTO based on life expectancy, and EuroQol 5-Dimension (EQ-5D) including a visual analog scale (VAS). The mean utility value and 95% CI were derived, and comparisons of subgroups using the t test and ANOVA were performed. We conducted a multilevel analysis after controlling the sociodemographic variables to consider repeated measures.

FINDINGS

A total of 155 participants were included in the survey. Their mean age was 39.7 years; 58.7% of participants were women. The mean health utility values for response and no response using TTO based on 10 years were 0.847 and 0.380, respectively. The estimated health utility values of response and no response were 0.865 and 0.476 using TTO based on life expectancy, and 0.814 and 0.279 using EQ-5D. For VAS, the response and no response were 0.744 and 0.322. After controlling the covariates, the important factors that affected utility values were response and no response to treatment (P < 0.001).

IMPLICATIONS

This study showed that the utility weights of people with no response to atopic dermatitis treatment were lower compared with response from the general population. Health care providers should therefore consider symptom control as an important factor affecting the quality of life of those with atopic dermatitis.

Validity of the EQ-5D in patients with pemphigus vulgaris and pemphigus foliaceus

BACKGROUND

No studies to date have employed the EuroQoL EQ-5D questionnaire to assess health-related quality of life (HRQoL) in patients with pemphigus.

OBJECTIVES

To evaluate the HRQoL of patients with pemphigus by the EQ-5D and to analyse the convergent and known-groups validity of the EQ-5D in this patient population.

METHODS

Between 2014 and 2017, a multicentre cross-sectional study was carried out. Outcome measures included the five-level EQ-5D (EQ-5D-5L), Dermatology Life Quality Index (DLQI), Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) and an average pain intensity visual analogue scale (VAS) for the past 3 months.

RESULTS

In total, 109 consecutive patients with pemphigus participated in the study (mean age 57 years; 64% women). Among the EQ-5D dimensions, the most problems were reported regarding pain/discomfort (50%), mobility (43%) and anxiety/depression (43%). No significant difference was found in mean EQ-5D index scores between patients with pemphigus vulgaris and those with pemphigus foliaceus (0·81 vs. 0·86, P = 0·14). The mean EQ-5D index scores of patients with limited, moderate, significant and extreme pemphigus were 0·88, 0·82, 0·72 and 0·67, respectively (P = 0·001). The number of comorbidities was associated with greater impairment in EQ-5D index scores (P < 0·001). DLQI (r_s = -0·62, P < 0·001) and the average pain intensity VAS (r_s = -0·59, P < 0·001) more strongly correlated with the EQ-5D index scores than did ABSIS (r_s = -0·40, P < 0·001).

CONCLUSIONS

This is the first study employing the EQ-5D questionnaire in pemphigus. The EQ-5D is a valid measure of HRQoL in patients with pemphigus that can be useful both in clinical practice and in economic evaluations to assess the health gains associated with new effective treatments.

Patient-reported outcomes in topical field treatment of actinic keratosis in Swedish and Danish patients

Topical treatments in dermatology can be long, complex and lead to nonadherence and nonpersistence to prescribed treatment. Clinical efficacy observed in randomized clinical trials (RCT) may therefore be reduced in real-world clinical practice. The objective of this study was to analyze patient-reported treatment adherence, treatment satisfaction and health-related quality of life (HRQoL) with topical treatments of actinic keratosis (AK) in routine clinical practice in Denmark and Sweden. Adult patients prescribed field-directed topical AK treatments with diclofenac gel, imiquimod or ingenol mebutate per routine clinical practice were eligible for the observational RAPID-ACT study. Data were collected through physician and patient questionnaires that included validated instruments to measure treatment satisfaction (TSQM-9), treatment adherence (MMAS) and HRQoL (EQ-5D-5L, EQ-VAS, AKQoL). In total, 446 patients from Denmark and Sweden were included. Ingenol mebutate patients reported a higher satisfaction with treatment effectiveness compared to patients treated with diclofenac (p = .006) while no other differences in treatment satisfaction could be determined. Treatment adherence was generally high, but higher for ingenol mebutate compared to both diclofenac (p < .001) and imiquimod (p = .007), possibly due to shorter treatment duration. No differences in improved HRQoL were found. More research is needed about the link between treatment adherence and real-world effectiveness.

Sustained Psoriasis Area and Severity Index, Dermatology Life Quality Index and EuroQol-5D response of biological treatment in psoriasis: 10 years of real-world data in the Swedish National Psoriasis Register

BACKGROUND

Few studies have analysed the long-term effects of biological treatment in psoriasis. PsoReg, the Swedish national register for systemic psoriasis treatment, started in 2006 and now includes 10 years of real-world data on the effectiveness of biological treatment.

OBJECTIVES

To analyse the long-term real-world outcome data of patients who are biologically naïve with moderate-to-severe psoriasis after switching to biological treatment.

METHODS

An observational study of patients who are biologically naïve with at least one registration of outcome before switching to biological treatment while included in PsoReg and at least one follow-up visit. Psoriasis Area and Severity Index (PASI), Dermatology Life Quality Index (DLQI) and EuroQol-5D (EQ-5D) values were analysed at 3-5 months, 6-11 months and at least once after ≥ 1 year, up to 9 years after the switch to biological treatment.

RESULTS

In total, 583 patients fulfilled the inclusion criteria. Of these, 399, 395 and 373 patients had observed outcome data beyond 1 year on the PASI, DLQI and EQ-5D, respectively, and 164, 168 and 152, respectively, were observed in at least three time periods after the switch. Significant (P < 0·01) improvement in PASI, DLQI and EQ-5D scores was observed 3-5 months after the switch and sustained under the whole observation period. The mean PASI, DLQI and EQ-5D changed from 13·5 ± 9·1, 9·0 ± 8·1 and 0·74 ± 0·22, respectively, before the switch, to 4·0 ± 3·5, 3·7 ± 4·7 and 0·79 ± 0·21, respectively, 1-5 years after the switch.

CONCLUSIONS

Biological treatment, as used in clinical practice, shows a stable long-term effectiveness in all the measured dimensions, PASI, DLQI and EQ-5D.

Mapping of the DLQI scores to EQ-5D utility values using ordinal logistic regression

Purpose

The Dermatology Life Quality Index (DLQI) and the European Quality of Life-5 Dimension (EQ-5D) are separate measures that may be used to gather health-related quality of life (HRQoL) information from patients. The EQ-5D is a generic measure from which health utility estimates can be derived, whereas the DLQI is a specialty-specific measure to assess HRQoL. To reduce the burden of multiple measures being administered and to enable a more disease-specific calculation of health utility estimates, we explored an established mathematical technique known as ordinal logistic regression (OLR) to develop an appropriate model to map DLQI data to EQ-5D-based health utility estimates.

Methods

Retrospective data from 4010 patients were randomly divided five times into two groups for the derivation and testing of the mapping model. Split-half cross-validation was utilized resulting in a total of ten ordinal logistic regression models for each of the five EQ-5D dimensions against age, sex, and all ten items of the DLQI. Using Monte Carlo simulation, predicted health utility estimates were derived and compared against those observed. This method was repeated for both OLR and a previously tested mapping methodology based on linear regression.

Results

The model was shown to be highly predictive and its repeated fitting demonstrated a stable model using OLR as well as linear regression. The mean differences between OLR-predicted health utility estimates and observed health utility estimates ranged from 0.0024 to 0.0239 across the ten modeling exercises, with an average overall difference of 0.0120 (a 1.6% underestimate, not of clinical importance).

Conclusions

This modeling framework developed in this study will enable researchers to calculate EQ-5D health utility estimates from a specialty-specific study population, reducing patient and economic burden.

Electronic supplementary material

The online version of this article (doi:10.1007/s11136-017-1607-4) contains supplementary material, which is available to authorized users.

The burden of common skin diseases assessed with the EQ5D™: a European multicentre study in 13 countries

BACKGROUND

Generic instruments measuring health-related quality of life (HRQoL), like EQ5D™, enable comparison of skin diseases with healthy populations and nondermatological medical conditions, as well as calculation of utility data.

OBJECTIVES

To measure HRQoL in patients with common skin diseases and healthy controls across Europe using the EQ5D.

METHODS

This multicentre observational cross-sectional study was conducted in 13 European countries. Each dermatology clinic recruited at least 250 consecutive adult outpatients to complete questionnaires, including the EQ5D.

RESULTS

There were 5369 participants (4010 patients and 1359 controls). Mean ± SD self-rated health state reported by patients was 69·9 ± 19·7; for controls it was 82·2 ± 15·5. When adjusted for confounding factors, including comorbidity, mean patient EQ visual analogue scores were 10·5 points lower than for controls (standardized β = -0·23). Odds ratio with 95% confidence interval for impairment in all five dimensions of EQ5D adjusted for confounders was doubled for patients compared with controls. Patients with hidradenitis suppurativa (HS), blistering conditions, leg ulcers, psoriasis and eczemas had the highest risk for reduction in HRQoL in most dimensions (2-10-fold). Data on differences of impairment by dimensions offer new insights.

CONCLUSIONS

This study confirms the large impact skin conditions have on patients' well-being, differentiating between aspects of HRQoL. Patients with HS, blistering diseases, leg ulcers, infections and most chronic skin diseases reported reduced HRQoL compared with patients with chronic obstructive lung disease, diabetes mellitus, cardiovascular disease and cancers. These findings are important in the prioritization of resource allocation between medical fields and within dermatological subspecialities.

Intralesional triamcinolone for flares of hidradenitis suppurativa (HS): A case series

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory disease of the hair follicle. Standard practice of managing acute flares with corticosteroid injection lacks scientific evidence.

OBJECTIVE

We sought to assess the outcomes of routine treatment using intralesional triamcinolone (triamcinolone acetonide 10 mg/mL) in the management of acute flares in HS.

METHODS

This was a prospective case series evaluating the effect of intralesional corticosteroids for alleviation of acute flares in HS. Physician- and patient-reported outcomes were noted.

RESULTS

Significant reductions in physician-assessed erythema (median score from 2-1, P < .0001), edema (median score from 2-1, P < .0001), suppuration (median score from 2-1, P < .0001), and size (median score from 3-1, P < .0001) was demonstrated at follow-up. A significant difference in patient-reported pain visual analog scale scores occurred after 1 day (from 5.5-2.3, P < .005) and from day 1 to day 2 (from 2.3-1.4, P < .002).

LIMITATIONS

Small study size, open single-arm design, and short follow-up time are the limitations of this study.

CONCLUSION

Intralesional injection of corticosteroids is perceived as beneficial by physicians and patients in the management of HS flares by reducing pain after 1 day and signs of inflammation approximately 7 days later.

Diagnosing Hidradenitis Suppurativa

Three diagnostic criteria must be met for hidradenitis suppurativa: typical lesions, occurrence in one or more of the predilection areas, and that it is chronic and/or recurrent. Several outcome measures are used, including patient-reported pain and itch scales, Dermatology Life Quality Index, and Skindex. Hidradenitis suppurativa is associated with significant comorbidities that must be addressed in the evaluation of the patients.

Health related quality of life in patients with actinic keratosis--an observational study of patients treated in dermatology specialist care in Denmark

Background

Actinic keratosis (AK) is a common skin condition that may progress to non-melanoma skin cancer (NMSC). The disease may influence Health Related Quality of Life (HRQoL), but studies of HRQoL in patients with AK are limited.

The purpose of the study was to analyze HRQoL in patients with different severity levels of AK treated in dermatology specialist care using generic and disease-specific HRQoL instruments and to analyze their relationship.

Methods

AK patients who visited dermatological clinics in Denmark were included in an observational, cross-sectional, study in a multi-center setting. Dermatologists assessed AK severity and patients completed: Actinic Keratosis Quality of Life Questionnaire (AKQoL), Dermatology Life Quality Index (DLQI), and EQ-5D-5 L including EQ-VAS. Differences between categorical subgroups were tested with Wilcoxon rank-sum test. The relationship between instruments was analyzed with the Spearman correlation test.

Results

A total of 312 patients were included in the analyses. Patients reported impairment in the disease specific HRQoL instrument AKQoL (mean AKQoL 6.7, DLQI 2, EQ-5D-5 L 0.88, and EQ-VAS 79). HRQoL was least affected in patients with mild actinic disease, whereas patients with severe actinic damage suffered from further impaired HRQoL (mean AKQoL 10.1 and DLQI 4.6). Correlations between DLQI and AKQoL were moderate, whereas the correlations between DLQI and EQ-5D-5 L and between AKQoL and EQ-5D-5 L were weak.

Conclusions

Patients with severe actinic damage showed more impairment in HRQoL than those with mild disease. Correlations between instruments suggest that they are complementary as they measure different aspects of HRQoL and are used for different purposes.

Development of a disease-specific version of the EQ-5D-5L for use in patients suffering from psoriasis: lessons learned from a feasibility study in the UK

OBJECTIVES

The EuroQol five-dimensional (EQ-5D) questionnaire is a generic measure widely used for the assessment of health status. Research has suggested that it may be insensitive to the burdens associated with particular conditions. This study was designed to explore the feasibility of developing and valuing a disease-specific "bolt-on" version of the EQ-5D questionnaire for use in psoriasis.

METHODS

A series of steps were undertaken to develop, test, and evaluate dimensions for a psoriasis-specific version of the EQ-5D questionnaire (hereafter referred to as the EQ-PSO questionnaire). Candidate dimensions were explored through a review of published literature, in-depth qualitative interviews with patients, and consultation with a clinical expert. A psychometric validation exercise was then undertaken to establish how well dimensions functioned. Two dimensions were selected for inclusion in a draft measure alongside the existing EQ-5D questionnaire dimensions: "skin irritation" and "self-confidence." Last, a time trade-off valuation exercise was conducted with 300 members of the UK general public to derive utilities for health states described by the measure.

RESULTS

The psychometric analyses indicated that the two new candidate dimensions captured additional variance over and above the existing five dimensions. Data from the valuation exercise were analyzed by using different models. A collapsed random effects model was put forward as a parsimonious and accurate approach. Based on this model, estimated utilities ranged from 0.98 ± 0.02 for state "1111111" to 0.03 ± 0.29 for state "5555555."

CONCLUSIONS

This study has developed the EQ-PSO questionnaire to support future psoriasis research and has informed the development of future bolt-on versions of the EQ-5D questionnaire.