Skip to main content
Key Specialties
Cardiology Diabetology Endocrinology Gastroenterology Geriatrics and Gerontology Gynecology and Obstetrics Hematology Infectious Disease Internal Medicine Nephrology Neurology Oncology Pediatrics Respiratory Medicine Rheumatology Surgery
Congress Coverage
2024 ACC Congress 2023 ESMO Congress 2023 EASD Congress 2023 ERS Congress 2023 ESC Congress
Clinical Collections
Advances in Alzheimer’s

At a glance: The STEP trials

A round-up of the STEP phase 3 clinical trials evaluating semaglutide for weight loss in people with overweight or obesity.
ADVANCED SEARCH
Log in
Top
Health and Quality of Life Outcomes
Published in: Health and Quality of Life Outcomes 1/2020

Open Access 01-12-2020 | Research

Dimensionality and psychometric analysis of DLQI in a Brazilian population

Authors: Marilia F. S. Jorge, Ticiane D. Sousa, Camila F. Pollo, Bianca S. R. Paiva, Mayra Ianhez, Juliana C. Boza, Silmara Meneguin, Juliano V. Schmitt, Daniel Holthausen Nunes, Joel C. Lastoria, Hélio A. Miot

Published in: Health and Quality of Life Outcomes | Issue 1/2020

Login to get access

Abstract

Background

The Dermatology Life Quality Index (DLQI) is the most commonly used instrument for clinical evaluation of the impact on health-related quality of life (HRQOL) in dermatological research protocols. The DLQI’s classical psychometric properties have been considered adequate in validation studies from several countries. However, the structure of the DLQI is a matter of discussion, especially concerning the dimensionality and informative properties of its questions according to the item response theory (IRT).

Methods

Pooled data from studies in Brazil that utilized the DLQI to assess HRQOL in 14 dermatoses were reanalyzed. Classical psychometrical analysis, dimensionality assessment through parallel analysis and IRT (Samejima’s ordinal model) analysis were performed.

Results

The sample consisted of 1286 patients with a mean age of 47 years (SD = 16), and the proportion of women was 59% (765). The DLQI scores ranged from 0 to 29, with a median (p25–p75) of 5 (2–11). All items indicated significant correlations with the total DLQI score (rho > 0.54). The Cronbach’s alpha result was 0.90 (CI 95% 0.89–0.91). Parallel analysis indicated a unidimensional factor structure. According to IRT analysis, items q6 (sports) and q7 (work/study) exhibited insufficient fit to the model (p < 0.01), while the items that indicated the best discrimination and information functions were q2 (embarrassment), q3 (shopping/gardening), q4 (clothing) and q5 (social/leisure). The ordination of the scores was confirmed for all items. Most items revealed non-uniform behavior according to sex, age and type of disease.

Conclusions

The DLQI exhibits adequate psychometric reliability and a unidimensional structure for assessing HRQOL in Brazilian dermatological patients. The DLQI’s performance varies in the assessment of HRQOL in heterogeneous samples.
Literature
1.
Nijsten T. Dermatology life quality index: time to move forward. J Invest Dermatol. 2012;132:11–3.PubMedCrossRef
2.
Sanchez J, Zakzuk J, Cardona R. Evaluation of a guidelines-based approach to the treatment of chronic spontaneous Urticaria. J Allergy Clin Immunol Pract. 2018;6:177–82 e1.PubMedCrossRef
3.
Baker C, Mack A, Cooper A, et al. Treatment goals for moderate to severe psoriasis: an Australian consensus. Australas J Dermatol. 2013;54:148–54.PubMedCrossRef
4.
Chernyshov PV, Tomas-Aragones L, Manolache L, et al. Which acne treatment has the best influence on health-related quality of life? Literature review by the European academy of dermatology and venereology task force on quality of life and patient oriented outcomes. J Eur Acad Dermatol Venereol. 2018;32:1410–9.PubMedCrossRef
5.
Finlay AY, Khan GK. Dermatology life quality index (DLQI)--a simple practical measure for routine clinical use. Clin Exp Dermatol. 1994;19:210–6.PubMedCrossRef
6.
He Z, Lu C, Basra MK, et al. Psychometric properties of the Chinese version of dermatology life quality index (DLQI) in 851 Chinese patients with psoriasis. J Eur Acad Dermatol Venereol. 2013;27:109–15.PubMedCrossRef
7.
Mork C, Wahl A, Moum T. The Norwegian version of the dermatology life quality index: a study of validity and reliability in psoriatics. Acta Derm Venereol. 2002;82:347–51.PubMedCrossRef
8.
Ozturkcan S, Ermertcan AT, Eser E, et al. Cross validation of the Turkish version of dermatology life quality index. Int J Dermatol. 2006;45:1300–7.PubMedCrossRef
9.
Takahashi N, Suzukamo Y, Nakamura M, et al. Japanese version of the dermatology life quality index: validity and reliability in patients with acne. Health Qual Life Outcomes. 2006;4:46.PubMedPubMedCentralCrossRef
10.
Lewis V, Finlay AY. 10 years experience of the dermatology life quality index (DLQI). J Investig Dermatol Symp Proc. 2004;9:169–80.PubMedCrossRef
11.
Ferraz LB, Almeida FA, Vasconcellos MR, et al. The impact of lupus erythematosus cutaneous on the quality of life: the Brazilian-Portuguese version of DLQI. Qual Life Res. 2006;15:565–70.PubMedCrossRef
12.
Martins GA, Arruda L, Mugnaini ASB. Validation of life quality questionnaires for psoriasis patients. An Bras Dermatol. 2004;79:521–35.CrossRef
13.
He Z, Lo Martire R, Lu C, et al. Rasch analysis of the dermatology life quality index reveals limited application to Chinese patients with skin disease. Acta Derm Venereol. 2018;98:59–64.PubMedCrossRef
14.
Hongbo Y, Thomas CL, Harrison MA, et al. Translating the science of quality of life into practice: what do dermatology life quality index scores mean? J Invest Dermatol. 2005;125:659–64.PubMedCrossRef
15.
Poor AK, Brodszky V, Pentek M, et al. Is the DLQI appropriate for medical decision-making in psoriasis patients? Arch Dermatol Res. 2018;310:47–55.PubMedCrossRef
16.
Twiss J, Meads DM, Preston EP, et al. Can we rely on the dermatology life quality index as a measure of the impact of psoriasis or atopic dermatitis? J Invest Dermatol. 2012;132:76–84.PubMedCrossRef
17.
Nijsten T, Meads DM, de Korte J, et al. Cross-cultural inequivalence of dermatology-specific health-related quality of life instruments in psoriasis patients. J Invest Dermatol. 2007;127:2315–22.PubMedCrossRef
18.
Nijsten T, Meads DM, McKenna SP. Dimensionality of the dermatology life quality index (DLQI): a commentary. Acta Derm Venereol. 2006;86:284–5.PubMedCrossRef
19.
Ofenloch RF, Diepgen TL, Weisshaar E, et al. Assessing health-related quality of life in hand eczema patients: how to overcome psychometric faults when using the dermatology life quality index. Acta Derm Venereol. 2014;94:658–62.PubMedCrossRef
20.
Liu Y, Li T, An J, et al. Rasch analysis holds no brief for the use of the dermatology life quality index (DLQI) in Chinese neurodermatitis patients. Health Qual Life Outcomes. 2016;14:17.PubMedPubMedCentralCrossRef
21.
Chren MM, Lasek RJ, Quinn LM, et al. Convergent and discriminant validity of a generic and a disease-specific instrument to measure quality of life in patients with skin disease. J Invest Dermatol. 1997;108:103–7.PubMedCrossRef
22.
Chren MM, Lasek RJ, Quinn LM, et al. Skindex, a quality-of-life measure for patients with skin disease: reliability, validity, and responsiveness. J Invest Dermatol. 1996;107:707–13.PubMedCrossRef
23.
Maranzatto CF, Miot HA, Miot LD, et al. Psychometrican analysis and dimensional structure of the Brazilian version of melasma quality of life scale (MELASQoL-BP). An Bras Dermatol. 2016;91:422–8.PubMedPubMedCentralCrossRef
24.
Pollo CF, Miot LDB, Meneguin S, et al. Factors associated with quality of life in facial melasma: a cross-sectional study. Int J Cosmet Sci. 2018;40:313–6.CrossRef
25.
26.
Silvares MR, Fortes MR, Miot HA. Quality of life in chronic urticaria: a survey at a public university outpatient clinic, Botucatu (Brazil). Rev Assoc Med Bras (1992). 2011;57:577–82.CrossRef
27.
Boza JC, Kundu RV, Fabbrin A, et al. Translation, cross-cultural adaptation and validation of the vitiligo-specific health-related quality of life instrument (VitiQoL) into Brazilian Portuguese. An Bras Dermatol. 2015;90:358–62.PubMedPubMedCentralCrossRef
28.
Nunes DH, Frode TS. Quality of life in basal cell carcinoma patients in Brazil: a pilot cross sectional study. Dermatol Surg. 2013;39:620–6.PubMedCrossRef
29.
30.
Borges APP, Pelafsky VPC, Miot LDB, et al. Quality of life with ingrown toenails: a cross-sectional study. Dermatol Surg. 2017;43:751–3.PubMedCrossRef
31.
Shimizu GKM, Wedy GF, Schaefer LV, et al. Translation into Portuguese language (Brazil), transcultural adaptation and validation of the quality of life questionnaire in female pattern hair loss (WAA-QoL-BP). An Bras Dermatol. 2018;93:701–6.PubMedPubMedCentralCrossRef
32.
Ianhez M, Pinto SA, Miot HA, et al. A randomized, open, controlled trial of tretinoin 0.05% cream vs. low-dose oral isotretinoin for the treatment of field cancerization. Int J Dermatol. 2019;58:365–73.PubMedCrossRef
33.
Gobo-Oliveira M, Pigari VG, Ogata MS, et al. Gabapentin versus dexchlorpheniramine as treatment for uremic pruritus: a randomised controlled trial. Eur J Dermatol. 2018;28:488–95.PubMedCrossRef
34.
Nijsten TE, Sampogna F, Chren MM, et al. Testing and reducing skindex-29 using Rasch analysis: Skindex-17. J Invest Dermatol. 2006;126:1244–50.PubMedCrossRef
35.
Horn JL. A rationale and test for the number of factors in factor analysis. Psychometrika. 1965;30:179–85.PubMedCrossRef
36.
O'Connor BP. SPSS and SAS programs for determining the number of components using parallel analysis and velicer's MAP test. Behav Res Methods Instrum Comput. 2000;32:396–402.PubMedCrossRef
37.
Lorenzo-Seva U, Timmerman ME, Kiers HA. The Hull method for selecting the number of common factors. Multivar Behav Res. 2011;46:340–64.CrossRef
38.
Timmerman ME, Lorenzo-Seva U. Dimensionality assessment of ordered polytomous items with parallel analysis. Psychol Methods. 2011;16:209–20.PubMedCrossRef
39.
Calderon Garrido C, Navarro Gonzalez D, Lorenzo Seva U, et al. Multidimensional or essentially unidimensional? A multi-faceted factor-analytic approach for assessing the dimensionality of tests and items. Psicothema. 2019;31:450–7.PubMed
40.
Ferrando PJ, Lorenzo-Seva U. Program FACTOR at 10: origins, development and future directions. Psicothema. 2017;29:236–40.PubMed
41.
42.
Deng L, Chan W. Testing the difference between reliability coefficients alpha and omega. Educ Psychol Meas. 2017;77:185–203.PubMedCrossRef
43.
Trizano-Hermosilla I, Alvarado JM. Best alternatives to Cronbach's alpha reliability in realistic conditions: congeneric and asymmetrical measurements. Front Psychol. 2016;7:769.PubMedPubMedCentralCrossRef
44.
Sijtsma K. On the use, the misuse, and the very limited usefulness of Cronbach's alpha. Psychometrika. 2009;74:107–20.PubMedCrossRef
45.
Jin S, Yang-Wallentin F. Asymptotic robustness study of the Polychoric correlation estimation. Psychometrika. 2017;82:67–85.PubMedCrossRef
46.
47.
48.
Kuo TC, Sheng Y. A comparison of estimation methods for a multi-unidimensional graded response IRT model. Front Psychol. 2016;7:880.PubMedPubMedCentral
49.
Crane PK, Gibbons LE, Jolley L, et al. Differential item functioning analysis with ordinal logistic regression techniques. DIFdetect and difwithpar. Med Care. 2006;44:S115–23.PubMedCrossRef
50.
Kutscher T, Eid M, Crayen C. Sample size requirements for applying mixed Polytomous item response models: results of a Monte Carlo simulation study. Front Psychol. 2019;10:2494.PubMedPubMedCentralCrossRef
51.
Jiang S, Wang C, Weiss DJ. Sample size requirements for estimation of item parameters in the multidimensional graded response model. Front Psychol. 2016;7:109.PubMedPubMedCentral
52.
Miot HA. Sample size in clinical and experimental studies. J Vasc Bras. 2011;10:275–8.CrossRef
53.
Lorenzo-Seva U, Ferrando PJ. FACTOR: a computer program to fit the exploratory factor analysis model. Behav Res Methods. 2006;38:88–91.PubMedCrossRef
54.
Chalmers RP. Mirt: a multidimensional item response theory package for the R environment. J Stat Softw. 2012;48:1–29.CrossRef
55.
56.
Carcano CBM, de Oliveira CZ, Paiva BSR, et al. The Brazilian version of Skindex-16 is a valid and reliable instrument to assess the health-related quality of life of patients with skin diseases. PLoS One. 2018;13:e0194492.PubMedPubMedCentralCrossRef
57.
Guimenes Albuquerque R, Grudtner Buratto G, Hirotsu C, et al. Comparison of quality of life evaluated by SF-36 and DLQI in multibacillary and paucibacillary leprosy patients from Sao Paulo, Brazil. Int J Dermatol. 2019;58:1415–22.PubMedCrossRef
58.
Silva MF, Fortes MR, Miot LD, et al. Psoriasis: correlation between severity index (PASI) and quality of life index (DLQI) in patients assessed before and after systemic treatment. An Bras Dermatol. 2013;88:760–3.PubMedPubMedCentralCrossRef
59.
Tavora IG, Bissoli GC, Miot HA, et al. Clinical manifestations and quality of life in hidradenitis suppurativa patients: survey of participants from an internet support group. An Bras Dermatol. 2019;94:298–303.PubMedPubMedCentralCrossRef
60.
Scotton MF, Miot HA, Abbade LP. Factors that influence healing of chronic venous leg ulcers: a retrospective cohort. An Bras Dermatol. 2014;89:414–22.PubMedPubMedCentralCrossRef
61.
Rencz F, Poor AK, Pentek M, et al. A detailed analysis of 'not relevant' responses on the DLQI in psoriasis: potential biases in treatment decisions. J Eur Acad Dermatol Venereol. 2018;32:783–90.PubMedCrossRef
62.
Rencz F, Gulacsi L, Pentek M, et al. DLQI-R scoring improves the discriminatory power of the dermatology life quality index in patients with psoriasis, pemphigus and morphea. Br J Dermatol. 2020;182:1167–75.PubMedCrossRef
63.
Garrido LE, Abad FJ, Ponsoda V. A new look at Horn's parallel analysis with ordinal variables. Psychol Methods. 2013;18:454–74.PubMedCrossRef
64.
Twiss J, McKenna SP. Comparing the impact of psoriasis and atopic dermatitis on quality of life: co-calibration of the PSORIQoL and QoLIAD. Qual Life Res. 2015;24:105–13.PubMedCrossRef
Metadata
Title
Dimensionality and psychometric analysis of DLQI in a Brazilian population
Authors
Marilia F. S. Jorge
Ticiane D. Sousa
Camila F. Pollo
Bianca S. R. Paiva
Mayra Ianhez
Juliana C. Boza
Silmara Meneguin
Juliano V. Schmitt
Daniel Holthausen Nunes
Joel C. Lastoria
Hélio A. Miot
Publication date
01-12-2020
Publisher
BioMed Central
Published in
Health and Quality of Life Outcomes / Issue 1/2020
Electronic ISSN: 1477-7525
DOI
https://doi.org/10.1186/s12955-020-01523-9

Other articles of this Issue 1/2020

Health and Quality of Life Outcomes 1/2020 Go to the issue

Research

Measurement invariance across gender and age groups, validity and reliability of the Chinese version of the short-form supportive care needs survey questionnaire (SCNS-SF34)

Research

The modifying role of physical activity in the cross-sectional and longitudinal association of health-related quality of life with physiological functioning-based latent classes and metabolic syndrome

Research

Complete resolution of urinary incontinence with treatment improved the health-related quality of life of children with functional daytime urinary incontinence: a prospective study

Research

The quality of life of the patients with diabetes type 2 using EQ-5D-5 L in Birjand

Research

Person-centred, occupation-based intervention program supported with problem-solving therapy for type 2 diabetes: a randomized controlled trial

Research

Cross-cultural adaptation and psychometric evaluation of the Yoruba version of the Back beliefs questionnaire among patients with chronic low-back pain