Dimensionality and psychometric analysis of DLQI in a Brazilian population

Jorge, Marília Formentini Scotton; Sousa, Ticiane Dionízio de; Pollo, Camila Fernandes; Paiva, Bianca Sakamoto Ribeiro; Ianhez, Mayra; Boza, Juliana Catucci; Meneguin, Silmara; Schmitt, Juliano Vilaverde; Nunes, Daniel Holthausen; Lastória, Joel Carlos; Miot, Hélio Amante

doi:10.1186/s12955-020-01523-9

Cited by 11 publications

(8 citation statements)

References 65 publications

(114 reference statements)

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“…Available data are controversial with regard to the dimensionality of DLQI: in accordance with our results some studies provided evidence supporting its unidimensionality [ 15 , 21 ], while other studies revealed a multidimensional structure of the scale [ 16 , 19 , 20 , 39 ]. Unidimensionality cannot be assessed without considering the content of the instrument [ 40 , 41 ].…”

Section: Discussionsupporting

confidence: 84%

“…Rasch models have previously been applied to investigate the psychometrics of the DLQI in various patient populations, including psoriasis, atopic dermatitis, hand eczema, neurodermatitis and chronic arsenic exposure [ 15 – 21 , 38 ]. Yet this is the first study to evaluate measurement functioning of the DLQI using a Rasch model considering both possible interpretations of NRRs.…”

Section: Discussionmentioning

confidence: 99%

“…An alternative measurement approach, a Rasch model analysis, may offer numerous advantages over classical test theory in evaluating psychometric performance of scales [ 14 ]. So far, a small number of studies have applied Rasch models to examine the psychometric properties of the DLQI in various skin diseases [ 15 – 21 ]; however, only one study concerned with psoriasis alone, and no studies differentiated between the two possible interpretations of NRRs. The objective of this study is therefore to (i) evaluate the psychometric properties of the DLQI in patients with psoriasis using a Rasch model analysis and (ii) to compare the measurement performance of DLQI when NRRs are scored as ‘0′ and ‘missing’.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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Purpose Eight of the ten items of the Dermatology Life Quality Index (DLQI) have a ‘not relevant’ response (NRR) option. There are two possible ways to interpret NRRs: they may be considered ‘not at all’ or missing responses. We aim to compare the measurement performance of the DLQI in psoriasis patients when NRRs are scored as ‘0’ (hereafter zero-scoring) and ‘missing’ (hereafter missing-scoring) using Rasch model analysis. Methods Data of 425 patients with psoriasis from two earlier cross-sectional surveys were re-analysed. All patients completed the paper-based Hungarian version of the DLQI. A partial credit model was applied. The following model assumptions and measurement properties were tested: dimensionality, item fit, person reliability, order of response options and differential item functioning (DIF). Results Principal component analysis of the residuals of the Rasch model confirmed the unidimensional structure of the DLQI. Person separation reliability indices were similar with zero-scoring (0.910) and missing-scoring (0.914) NRRs. With zero-scoring, items 6 (sport), 7 (working/studying) and 9 (sexual difficulties) suffered from item misfit and item-level disordering. With missing-scoring, no misfit was observed and only item 7 was illogically ordered. Six and three items showed DIF for gender and age, respectively, that were reduced to four and three by missing-scoring. Conclusions Missing-scoring NRRs resulted in an improved measurement performance of the scale. DLQI scores of patients with at least one vs. no NRRs cannot be directly compared. Our findings provide further empirical support to the DLQI-R scoring modification that treats NRRs as missing and replaces them with the average score of the relevant items.

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Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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“…There is evidence that the DLQI may have limited cross-cultural equivalence as it has been shown that patients with similar levels of underlying health-related quality of life respond differently to DLQI items [45,46]. The psychometric properties of the DLQI have been studied in different ethnic populations to determine if the instrument meets the requirements of modern test theory [46][47][48]. Research has found that the DLQI has not evolved and introduces a form of selection bias [46,49,50] since more than half the questions are affected by external factors such as age, gender, diagnosis, and nationality [46].…”

Section: Discussionmentioning

confidence: 99%

Outcomes of Biologic Use in Asian Compared with Non-Hispanic White Adult Psoriasis Patients from the CorEvitas Psoriasis Registry

Chen

Wang

Burge

et al. 2022

Dermatol Ther (Heidelb)

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Introduction: Real-world data are limited comparing Asian and White patients with psoriasis using biologic therapy. This study compared the 6-month effectiveness of biologic therapy between Asian and White plaque patients with psoriasis in the CorEvitas Psoriasis Registry. Methods: Analyses included biologic initiations and 6-month follow-up visits from self-identified Asian (n = 293) and White (n = 2314) patients in the USA/Canada (4/2015-4/2020).Outcomes included: Psoriasis Area Severity Index (PASI) 75, disease activity measures [body surface area (BSA) B 1, BSA B 3, PASI90, PASI100, Investigator's Global Assessment (IGA) 0/1], and patient-reported outcomes [Dermatology Life Quality Index (DLQI) 0/1, itch, fatigue, skin pain, EuroQoL visual analog scale (EQ-VAS), patient global assessment, Work Productivity Activity and Impairment (WPAI) domains]. Unadjusted regression models were used to calculate odds ratios (OR) and 95% confidence intervals (CI) for achievement of binary outcomes and difference in mean change in continuous outcomes (b, 95% CI) at 6 months, followed by adjustment for age, sex, body mass index, alcohol, smoking, health insurance, education, comorbidities, scalp psoriasis morphology, psoriatic arthritis, biologic class, previous biologics, and baseline outcome value. Results: Asians had lower proportions of women (32.8% versus 49.1%) and obesity (27.3% versus 54.5%), and higher proportions on Medicaid (19.9% versus 8.8%), graduated college (50.9% versus 40.1%) and never smoked (67.1% versus 44.1%). In unadjusted analyses, Asians had 52% higher odds of achieving PASI75 versus White patients (OR 1.52; 95% CI 1.15, 2.02). After adjustment, the association was attenuated (OR 1.11; 0.81, 1.52). Secondary outcomes experienced similar patterns except for DLQI: Asians had 33% lower odds of achieving DLQI 0/1 in both the unadjusted

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“…The predominantly mild to moderate impact on HRQOL is common in dermatological series and requires instruments with su cient discrimination in this impact range. (4,11,(27)(28)(29)(30)(31)(32)(33) The three instruments studied demonstrated adequate feasibility, internal consistencies, temporal stability, and sensitivity to change. The Sk-17 subscale of symptoms exhibited small psychometric indicators.…”

Section: Discussionmentioning

confidence: 99%

Psychometric Comparison of the Performance of Quality of Life Assessment Instruments in Dermatology—the DLQI, Skindex-16, and Skindex-17—in a Brazilian Population.

Mfs

et al. 2021

Preprint

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Background: The DLQI (Dermatology Life Quality Index) is the most commonly used instrument for evaluating the quality of life in dermatology. Skindex was developed as a multidimensional instrument with successive versions published, the most recent being Skindex-16 and Skindex-17, both derived from Skindex-29 through different techniques. This study aimed to compare the three instruments—the DLQI, Skindex-16, and Skindex-17—according to their psychometric performance to refine the assessment of the quality of life among dermatological patients.Methods: A methodological study compared the psychometric performance of the DLQI, Skindex-16 (Sk-16), and Skindex-17 (Sk-17) instruments among adults with dermatoses that were classified according to characteristic physical symptoms and psychological or social domains. Analyses were performed to assess internal consistency, correlation, test-retest reproducibility, and responsiveness according to classical psychometry and to test discrimination and difficulty according to the item response theory.Results: The sample consisted of 229 patients predominantly women (71%) of adult age (average 45 years) and intermediate phototypes (III and IV = 73%). The analyses of internal consistency for the instruments resulted in Cronbach-α coefficients >0.80. There was adequate test-retest reproducibility and responsiveness for all dimensions of the instruments. The IRT (Iten Response Theory) analysis indicated adequate ordering and discrimination (a >1.0) for all items of the DLQI, Sk-16, and Sk-17; four items of Sk-16 did not adequately adhere to the TRI model (p <0.01 ). The items with the greatest discrimination were q3 (domestic activities) and q5 (leisure activities) in the DLQI; F2 (desire to be with people) and E6 (annoyance) in Sk-16; and S4 (irritated skin), P5 (relationship), and P6 (autonomy of tasks) in Sk-17. The Sk-16 and Sk-17 instruments presented more items that registered mild impacts on the quality of life (b <-0.5).Conclusions: The DLQI, Sk-16, and Sk-17 presented adequate psychometric performance for the assessment of health-related quality of life in a Brazilian sample. The multidimensional instruments (Sk-16 and Sk-17) were more sensitive to mild impacts on quality of life.

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Dimensionality and psychometric analysis of DLQI in a Brazilian population

Cited by 11 publications

References 65 publications

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

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

Outcomes of Biologic Use in Asian Compared with Non-Hispanic White Adult Psoriasis Patients from the CorEvitas Psoriasis Registry

Psychometric Comparison of the Performance of Quality of Life Assessment Instruments in Dermatology—the DLQI, Skindex-16, and Skindex-17—in a Brazilian Population.

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