Dermatology Life Quality Index (DLQI)

DESCRIPTION:
The Dermatology Life Quality Index is the most used dermatologic-specific health-related quality of life (HRQoL) instrument. The DLQI is a self-administered, validated 10-question assessment that covers 6 aspects of a subject's HRQoL over the prior week: symptoms and feelings, daily activities, leisure, work/school, personal relationships, and treatment. The DLQI total score is calculated by summing the scores of each question for a total score that ranges from 0 to 30.^1-3

DISEASE STATES: 
36 different dermatologic conditions, including psoriasis and atopic dermatitis³

VALIDATED USES: 
Measure patient disability, treatment monitoring, disease impact/severity

ADMINISTRATION METHOD:
Patient

COMMONLY USED IN:
Clinical trials, research, clinical practice

DETAILED DESCRIPTION:
The Dermatology Life Quality Index was developed in 1994 and is the most frequently used patient-reported outcome measure in dermatological clinical trials.^1,4 The DLQI consists of 10 self-administered questions that focus on the impact of a patient’s skin disease related to 6 functional domains: symptoms and feelings, daily activities, leisure, work and school, personal relationships, and treatment.^1-3

Each question is scored on a 4-point scale that ranges from 0 to 3. The 10 scores are added together for a total score that ranges from 0 (no impairment of life quality) to 30 (maximum impairment).^1-3 The higher the score, the more a patient’s quality of life is impaired.^1,2

DLQI FOUR-POINT LIKERT SCALE^1,5,6 

DLQI SUBSCALES^1,5,6

Note: Question 7 may be a two-part question depending on “yes/no” response. If the answer is “yes,” it is scored as 3. If the answer is “no,” then a follow-up question is used to determine if there is any effect, with three possible responses that range from 0 to 2.^1,5,6

DLQI SCORING⁶

VALIDITY:
The DLQI is sensitive to detecting change in patients’ QoL before and after treatment, in clinical trials, and in clinical practice.² It has demonstrated high repeatability and specificity, with mean scores of the normal population that range from 0 to 0.5.³ Basra et al. 2008 reviewed 272 different publications about the DLQI use in clinical research and its psychometric properties. The DLQI has demonstrated test-retest reliability across 12 international studies (0.56 to 0.99). Internal consistency has been established across 22 studies (0.75 to 0.92). The DLQI has demonstrated construct validity across 37 publications.²

LIMITATIONS:
The DLQI may underestimate disease severity for respondents who choose a “not relevant” response (NRR) to one or more questions.⁷ The variability of how NRRs are interpreted may lead to bias in HRQoL assessments, thus precluding meaningful comparisons across psoriasis patients.⁸ There may be inherent item bias, where responses may be affected by external factors such as gender, age, culture, and diagnosis.⁹ It has been purported to have low conceptual validity because more questions focus on physical limitations than on the psychological impact of a patient’s skin disease.¹⁰

This resource is intended for educational purposes only and is intended for US healthcare professionals. Healthcare professionals should use independent medical judgment. All decisions regarding patient care must be handled by a healthcare professional and be made based on the unique needs of each patient.

References: 1. Finlay AY, Khan GK. Dermatology Life Quality Index (DLQI)—a simple practical measure for routine clinical use. Clin Exp Dermatol. 1994;19(3):210-216. doi:10.1111/j.1365-2230.1994.tb01167.x 2. Basra MKA, Fenech R, Gatt RM, Salek MS, Finlay AY. The Dermatology Life Quality Index 1994-2007: a comprehensive review of validation data and clinical results. Br J Dermatol. 2008;159(5):997-1035. doi:10.1111/j.1365-2133.2008.08832.x 3. Lewis V, Finlay AY. 10 years experience of the Dermatology Life Quality Index (DLQI). J Investig Dermatol Symp Proc. 2004;9(2):169-180. doi:10.1111/j.1087-0024.2004.09113.x 4. Basra MKA, Salek MS, Camilleri L, Sturkey R, Finlay AY. Determining the minimal clinically important difference and responsiveness of the Dermatology Life Quality Index (DLQI): further data. Dermatology. 2015;230(1):27-33. doi:10.1159/000365390 5. Marks R, Barton SP, Shuttleworth D, Finlay AY. Assessment of disease progress in psoriasis. Arch Dermatol. 1989;125(2):235-240. 6. Hongbo Y, Thomas CL, Harrison MA, Salek MS, Finlay AY. Translating the science of quality of life into practice: what do Dermatology Life Quality Index scores mean? J Invest Dermatol. 2005;125(4):659-664. doi:10.1111/j.0022-202X.2005.23621.x 7. Barbieri JS, Gelfand JM. Influence of "not relevant" responses on the Dermatology Life Quality Index (DLQI) for patients with psoriasis in the United States. JAMA Dermatol. 2019;155(6):743-745. doi:10.1001/jamadermatol.2018.5655 8. Rencz F, Mitev AZ, Szabó Á, et al. A Rasch model analysis of two interpretations of 'not relevant' responses on the Dermatology Life Quality Index (DLQI). Qual Life Res. 2021;30(8):2375-2386. doi:10.1007/s11136-021-02803-7 9. 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(10):2315-2322. doi:10.1038/sj.jid.5700875 10. Muldoon MF, Barger SD, Flory JD, Manuck SB. What are quality of life measurements  measuring? BMJ. 1998;316(7130):542-545. doi: 10.1136/bmj.316.7130.542