A Rasch model analysis of two interpretations of 'not relevant' responses on the Dermatology Life Quality Index (DLQI)

Patient and family burden in pediatric atopic dermatitis and its treatment pattern in Japan

BACKGROUND

This study evaluated the level of burden in pediatric and adolescent atopic dermatitis (AD) patients in Japan, the associated burden on caregivers/families, and whether this burden varied with age.

METHODS

Data were drawn from the Adelphi Pediatric AD Disease Specific Programme (DSP)™, a cross-sectional survey of physicians and their patients conducted in Japan between July and December 2022. Physicians reported patient demographics, clinical characteristics, disease burden, and current/previous therapies. Patients and/or caregivers reported perceived disease severity and impact of AD, including the Children's Dermatology Life Quality Index (CDLQI) and Dermatitis Family Impact questionnaire (DFI).

RESULTS

Overall, 55 physicians provided data for 537 AD patients aged ≤17. Mean (SD) overall scores for CDLQI, POEM, and DFI were 9.3 (6.3), 8.3 (6.8), and 11.7 (7.2), respectively. Age was associated with higher patient and/or caregiver-reported CDLQI scores, which increased by 0.543 points per year of age (P = 0.01). Patients with severe disease reported a more significant impact on quality of life factors compared with mild patients (P < 0.001). Age was associated with higher caregiver-reported burden, with DFI scores increasing by 0.325 per year (P = 0.01). Physician-reported impact on caregivers showed that age was significantly associated with increased burden on sleep, daily activities, work, and mood (P < 0.05), with disease severity associated with impact across all factors (P < 0.01).

CONCLUSIONS

Both increasing age and disease severity were associated with the increased impact of AD on patients and their caregivers. Disease control/modification through appropriate therapeutic intervention at a younger age may relieve the burden of pediatric AD on patients and their families.

Patient-Reported Outcome Measures for Health-Related Quality of Life in Patients With Psoriasis: A Systematic Review

Importance

Multiple patient-reported outcome measures (PROMs) for health-related quality of life (HRQL) exist for patients with psoriasis. Evidence for the content validity and other measurement properties of these PROMs is critical to determine which HRQL PROMs could be recommended for use.

Objective

To systematically review the validity of HRQL-focused PROMs used in patients with psoriasis.

Evidence Review

Using PubMed and Embase, full-text articles published in English or Spanish on development or validation studies for psoriasis-specific, dermatology-specific, or generic HRQL PROMs were included. Development studies included original development studies, even if not studied in psoriasis patients per Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN) recommendations. If a study included multiple diagnoses, more than 50% of patients had to have psoriasis or psoriasis-specific subgroup analyses available. Data extraction and analysis followed the COSMIN guidelines. Two independent reviewers extracted and analyzed the data, including PROM characteristics, quality of measurement properties (structural validity, internal consistency, cross-cultural validity, reliability, measurement error, criterion validity, construct validity, and responsiveness), and level of evidence. PROMs were classified into 3 levels of recommendations: (1) PROM recommended for use; (2) PROM requires further validation; and (3) PROM not recommended for use.

Findings

Overall, 97 articles were identified for extraction. This included 19 psoriasis-specific, 8 skin-specific, and 6 generic PROMs. According to COSMIN standards, most measures identified received a B recommendation for use, indicating their potential but requiring further validation. Only the Rasch reduced version of the Impact of Psoriasis Questionnaire (IPSO-11 Rasch) received an A recommendation for use given that it had sufficient content validity, structural validity, and internal consistency.

Conclusions and Relevance

This study identified a significant lack of information concerning the quality of HRQL measures in psoriasis. This gap in knowledge can be attributed to the fact that traditional measures were developed using validation criteria that differ from the current standards in use. Consequently, additional validation studies in accordance with contemporary standards will be useful in aiding researchers and clinicians in determining the most suitable measure for assessing HRQL in patients with psoriasis.

Rasch analysis of the dermatology life quality index (DLQI) in patients with mild to moderate-severe psoriasis

Background The Dermatology Life Quality Index (DLQI) is a valuable tool for assessing the quality of life in adult patients with psoriasis. Aims To analyse the reliability and validity of the DLQI to measure the quality of life in patients with mild to moderate-severe psoriasis. Methods This was a secondary validation study nested in a follow-up study. The Rasch-Andrich model was utilised to perform response function, item and person fit, differential item functioning, dimensionality, and reliability analyses. Results A total of 1439 patients were analysed, 52.1% male, mean age of 48.7 years (SD 16.1). Psoriasis vulgaris was the phenotype in 43.1% of patients, and 86% had a mild Psoriasis Area Severity Index (PASI). Adequate adjustment of the response function and the items was observed in the best-fit sample, except for item 7 (work and study). The measure explained 60.9% of the variance and presented a reliability of 0.86. Differential item functioning was identified by age, with a relevant bias in the estimation for older adults. Item-person maps are provided. Limitations This study was performed at a single centre, with most patients presenting a mild PASI score, limiting generalisation of the findings. Conclusion The validity evidence favours the use of the DLQI in moderate-severe psoriasis. However, the instrument biases the estimate of older adults. This population group should consider a specific version of the instrument.

Evidence of the content validity, acceptability, and feasibility of a new Patient-Reported Impact of Dermatological Diseases measure

Background

The Global Research on the Impact of Dermatological Diseases (GRIDD) team is developing the new Patient-Reported Impact of Dermatological Diseases (PRIDD) measure of the impact of dermatological conditions on the patient's life, in partnership with patients. To develop PRIDD, we conducted a systematic review, followed by a qualitative interview study with 68 patients worldwide and subsequently a global Delphi survey of 1,154 patients to ensure PRIDD items were meaningful and important to patients.

Objective

To pilot test PRIDD with patients with dermatological conditions, focusing on its content validity (comprehensiveness, comprehensibility, and relevance), acceptability, and feasibility.

Methods

We conducted a theory-led qualitative study using the Three-Step Test-Interview method of cognitive interviewing. Three rounds of semi-structured interviews were conducted online. Adults (≥ 18 years) living with a dermatological condition and who spoke English sufficiently to take part in the interview were recruited through the International Alliance of Dermatology Patient Organizations' (GlobalSkin) global membership network. The topic guide met the gold-standard COSMIN (Consensus-based Standards for the Selection of Health Measurement Instruments) standards for cognitive interviewing. Analysis followed the thematic analytical model of cognitive interviewing.

Results

Twelve people (58% male) representing six dermatological conditions from four countries participated. Overall, patients found PRIDD to be comprehensible, comprehensive, relevant, acceptable, and feasible. Participants were able to discern the conceptual framework domains from the items. Feedback resulted in: the recall period being extended from 1 week to 1 month; removal of the 'not relevant' response option; and changes to the instructions and item ordering and wording to improve clarity and increase respondents' confidence in their ability to respond. These evidence-based adjustments resulted in a 26-item version of PRIDD.

Conclusion

This study met the gold-standard COSMIN criteria for the pilot testing of health measurement instruments. The data triangulated our previous findings, in particular the conceptual framework of impact. Our findings illuminate how patients understand and respond to PRIDD and other patient-reported measurement instruments. The results of comprehensibility, comprehensiveness, relevance, acceptability, and feasibility of PRIDD provide evidence of content validity from the target population. The next step in the development and validation of PRIDD is psychometric testing.

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.

Normative data and socio-demographic determinants of the Dermatology Life Quality Index in a large online sample of the Hungarian population

BACKGROUND

Population norms are available for several generic health-related quality of life questionnaires, but rarely for disease- or specialty-specific questionnaires.

OBJECTIVES

The aim of our study was to calculate population norms for the Dermatology Life Quality Index (DLQI) score.

METHODS

We conducted an online self-completed questionnaire survey on a large sample of the general Hungarian adult population. Respondents' socio-demographic characteristics and dermatology-related quality of life aspects were recorded.

RESULTS

A total of 2,001 participants completed the questionnaire, with the average age of 48.2 (SD = 16.6) years, half of the respondents in our sample (n = 981) reported long-standing health problems. The average DLQI score was 1.9 (SD = 4.0) with women having a higher average (2.0, SD = 3.9) than men (1.8, SD = 4.0; p=<0.001). The DLQI score differed among age-groups with younger people having relatively higher DLQI averages. When the multivariate linear regression model was applied, it showed that young age, lower income and unemployment status were associated with higher DLQI scores, while controlling for the existence of skin disease (p<0.05).

CONCLUSIONS

This study esthablished DLQI population norms among the general population, which may provide a reference point in health-policy and financing decision-making.

General and Skin-Specific Health-Related Quality of Life in Patients With Atopic Dermatitis Before and During the COVID-19 Pandemic

BACKGROUND

Few studies have investigated health-related quality of life (HRQoL) in patients with atopic dermatitis (AD) during the COVID-19 pandemic.

OBJECTIVES

The objectives of this study were to compare HRQoL in adult AD patients before and during the pandemic and to assess measurement performance of 4 HRQoL measures.

METHODS

Between 2018 and 2021, a multicenter, cross-sectional survey was conducted, involving 218 adult AD patients. Health-related quality of life outcomes included the EQ-5D-5L, Skindex-16, Dermatology Life Quality Index (DLQI), and DLQI-Relevant (DLQI-R). Severity was measured using objective SCORing Atopic Dermatitis, Eczema Area and Severity Index, and Investigator Global Assessment.

RESULTS

The mean ± SD EQ-5D-5L utility, Skindex-16, DLQI, and DLQI-R scores were 0.82 ± 0.22, 56.84 ± 27.46, 13.44 ± 8.46, and 13.76 ± 8.60, respectively. The patients reported more problems during the pandemic (P < 0.05) regarding pain/discomfort (odds ratio [OR], 1.78), worrying (OR, 1.89), concerns about persistence/reoccurrence of disease (OR, 1.88), and social relationships (OR, 1.69). The HRQoL outcomes showed strong correlations with each other (range of rs, |0.69| to |0.99|). The Skindex-16, DLQI, and DLQI-R were able to discriminate between severity groups with large (η2 = 0.20-0.23), whereas the EQ-5D-5L with moderate effect sizes (η2 = 0.08-0.11).

CONCLUSIONS

Atopic dermatitis patients experienced significantly more problems in some areas of HRQoL during the pandemic. The EQ-5D-5L, Skindex-16, DLQI, and DLQI-R demonstrated good convergent and known-group validity and can be suitable instruments for HRQoL assessment in clinical and research settings.

Impact of Psoriasis on Quality of Life

Psoriasis is a multisystem disorder with a significant impact on the quality of life (QoL) of the patient. QoL in psoriasis is influenced by epidemiological factors, the type and extent of the disease, and underlying comorbidities. Various tools have been developed to assess the QoL in patients with psoriasis, namely psoriasis specific, skin specific, generic QoL, and mixed measures. In this review, we present a concise overview of the different indices and the pros and cons of various tools to assess the impact of psoriasis on patients.

A comparative study on the measurement properties of Dermatology Life Quality Index (DLQI), DLQI-Relevant and Skindex-16

BACKGROUND

Dermatology Life Quality Index (DLQI) and Skindex-16 are among the most commonly used dermatology-specific health-related quality-of-life (HRQoL) instruments. DLQI has two common scoring methods, the original and the DLQI-Relevant (DLQI-R) modification. Head-to-head comparisons of the measurement properties of the DLQI, DLQI-R and Skindex-16 are currently lacking.

OBJECTIVES

We aim to compare the measurement properties of the DLQI, DLQI-R and Skindex-16.

METHODS

We analysed data from 618 patients with self-reported physician-diagnosed dermatological conditions from a cross-sectional survey carried out in Hungary in early 2020. DLQI, DLQI-R and Skindex-16 were compared in terms of ceiling and floor effects, informativity, convergent validity and known-group validity.

RESULTS

Mean DLQI, DLQI-R and Skindex-16 total scores were 3·76 ± 5·03, 4·11 ± 5·34 and 29·36 ± 26·62, respectively. Among patients with a DLQI/DLQI-R total score of zero, 64% reported problems on Skindex-16. Overall, 23-38% of patients with 'not relevant' responses on DLQI items 3 (shopping/home/gardening), 7 (working/studying), 8 (interpersonal problems) and 9 (sexual difficulties) reported problems on their corresponding Skindex-16 items. Average relative informativity (Shannon's evenness index) was the highest for Skindex-16 (0·85), followed by DLQI-R (0·66) and DLQI (0·54). DLQI, DLQI-R and Skindex-16 demonstrated similar convergent validity. DLQI was able to better discriminate between known groups of patients based on overall skin-related HRQoL impairment, whereas DLQI-R and Skindex-16 performed better with respect to self-perceived health status.

CONCLUSIONS

Skindex-16 seems to be more sensitive than DLQI/DLQI-R in capturing mild impairment in HRQoL. Our findings help to provide a fuller understanding of the difference between DLQI, DLQI-R and Skindex-16 and support the informed choice of instrument for clinical and research purposes.

Measurement properties of the ICECAP-A capability well-being instrument among dermatological patients

BACKGROUND

Capability well-being captures well-being based on people's ability to do the things they value in life. So far, no capability well-being measures have been validated in dermatological patients.

OBJECTIVES

To validate the adult version of the ICEpop CAPability measure (ICECAP-A) in patients with dermatological conditions. We aimed to test floor and ceiling effects, structural, convergent and known-group validity, and measurement invariance.

METHODS

In 2020, an online, cross-sectional survey was carried out in Hungary. Respondents with self-reported physician-diagnosed dermatological conditions completed the ICECAP-A, Satisfaction with Life Scale (SWLS), WHO-5 Well-Being Index and two dermatology-specific measures, Dermatology Life Quality Index (DLQI) and Skindex-16.

RESULTS

618 respondents (mean age 51 years) self-reported a physician-diagnosed dermatological condition, with warts, eczema, onychomycosis, acne and psoriasis being the most common. ICECAP-A performed well with no floor and mild ceiling effects. The violation of local independence assumption was found between the attributes of 'attachment' and 'enjoyment'. ICECAP-A index scores correlated strongly with SWLS and WHO-5 (r_s = 0.597-0.644) and weakly with DLQI and Skindex-16 (r_s = - 0.233 to - 0.292). ICECAP-A was able to distinguish between subsets of patients defined by education and income level, marital, employment and health status. Multigroup confirmatory factor analysis indicated measurement invariance across most of these subgroups.

CONCLUSIONS

This is the first study to validate a capability well-being measure in patients with dermatological conditions. The ICECAP-A was found to be a valid tool to assess capability well-being in dermatological patients. Future work is recommended to test measurement properties of ICECAP-A in chronic inflammatory skin conditions.