Patients and methods
Participants and settings
A nationwide questionnaire-based study was conducted in 21 hospitals and clinics in Korea from July 2015 to June 2016. All patients aged ≥ 20 years diagnosed with vitiligo by dermatologists, and who provided written informed consent prior to the survey were enrolled. We restricted the participants to adult patients, because different questionnaires should be applied to children and adults. We explored demographic characteristics and vitiligo phenotypes and determined Skindex-29 scores. All patients first completed the questionnaires in paper-and-pencil format, and dermatologists then confirmed the clinical profiles after interviewing and examining the patients. The study protocol was designed in accordance with the Declaration of Helsinki and was approved by the institutional review board of each hospital.
Demographic characteristics recorded included age, sex, marital status (single or married) and educational background (elementary school graduate, middle school graduate, high school graduate or college graduate).
The vitiligo phenotypes included subtype (segmental or nonsegmental), disease duration (< 1, 1–4, 5–9 or ≥ 10 years), affected body surface area (BSA; < 05, 05–09, 1–4, 5–9, 10–19 or ≥ 20%), involvement of visible body parts (yes or no) and the particular body parts involved (face and neck, scalp, upper extremities, lower extremities, trunk and genital area).
The Skindex-29 questionnaire
QoL was assessed using the Korean version of Skindex-29. This instrument is employed extensively to measure the effects of skin disease on a patient’s life;8,9 the Korean version was cross-culturally adapted by Ahn et al.10 The semantic equivalence of all back-translated items has been confirmed,10 and the Korean version has been validated by several previous studies.11–13 The questionnaire contains 29 items exploring the influence of skin disease on daily life using a five-point scale: 0 (never), 1 (rarely), 2 (sometimes), 3 (often) and 4 (all the time). The responses were transformed into linear scores varying from 0 (no effect) to 100 (effect always experienced). Each item belongs to one of three domains (symptoms, functioning and emotions); the scores of the three domains were calculated as the mean score of the items included in each domain.
The major items affecting patients with vitiligo
The proportions of patients affected by each item (sometimes, often and all the time) were calculated. The items of most concern were identified based on the answers.
The outcomes of the study were mild or severe impairment of QoL, as determined by each domain (symptoms, functioning and emotions) of Skindex-29. Mild and severe QoL impairments were defined using the cut-off scores suggested by Prinsen et al.:14,15 ≥ 39 (mild) and ≥ 52 (severe) for symptoms, ≥ 21 (mild) and ≥ 37 (severe) for functioning, and ≥ 24 (mild) and ≥ 39 (severe) for emotions.
Absolute and percentage frequencies were determined for categorical variables, and position (mean and median) and scattering (SD, range) were described for continuous variables. Univariate and multivariate logistic regression analyses were sequentially performed to identify the factors independently associated with QoL impairment in each domain of Skindex29. All analyses were performed using R 3.3.1 (R Foundation for Statistical Computing, Vienna, Austria).
In total, 1123 patients with vitiligo were recruited from 21 hospitals and clinics. Of the participants, 609 (542%) were male and 514 female (458%), with a mean age of 498 152 years (range 20–84). The median duration of disease was 30 years (range 0–60). The detailed clinical characteristics of the enrolled patients are summarized in Table 1.
The results of Skindex-29
The Skindex-29 items of most concern to patients with vitiligo were as follows: no. 13: I worry that my skin condition may get worse (746% of patients); no. 3: I worry that my skin condition may be serious (629%); no. 22: My skin condition is a problem for the people I love (556%); and no. 6: My skin condition makes me feel depressed (535%) (Table 2).
Impaired quality of life and associated factors in terms of the symptoms domain
Of the patients with vitiligo, 146% (164 of 1123) had mild and 52% (58 of 1123) had severe QoL impairment in terms of the symptoms domain (Fig. 1). On multivariate logistic
Table 1 The clinical characteristics of the 1123 patients with vitiligo included in the present study
regression modelling, the involvement of visible body parts (OR 153) and a larger affected BSA (compared with < 05%; 5–9%: OR 278, 10–19%: OR 284 and ≥ 20%: OR 469) were associated with mild symptom impairment (Table 3). A larger affected BSA was also associated with severe symptom impairment (compared with < 05%; ≥ 20%: OR 810).
Impaired quality of life and associated factors in terms of the functioning domain
Of the patients with vitiligo, 488% (548 of 1123) had mild and 282% (317 of 1123) had severe QoL impairment in terms of the functioning domain. The factors associated with
Table 2 The Skindex-29 items that affected > 25% of patients with vitiligo
Items (in order of frequency) patients Domain
13. I worry that my skin condition may 746% Emotions get worse
3. I worry that my skin condition may 629% Emotions be serious
22. My skin condition is a problem for 556% Functioning the people I love
6. My skin condition makes me feel 535% Emotions depressed
9. I worry about getting scars from my 498% Emotions skin condition
12. I am ashamed of my skin condition 497% Emotions
28. I am annoyed by my skin condition 476% Emotions
5. My skin condition affects my social 450% Functioning life
15. I am angry about my skin condition 448% Emotions
24. My skin is sensitive 433% Symptoms
4. My skin condition makes it hard to 427% Functioning work or do hobbies
21. I am embarrassed by my skin 410% Emotions condition
19. My skin is irritated 379% Symptoms
23. I am frustrated by my skin condition 356% Emotions
20. My skin condition affects my 354% Functioning interactions with others
11. My skin condition affects how close 328% Functioning
I can be with those I love
17. My skin condition makes showing 305% Functioning affection difficult
26. I am humiliated by my skin 296% Emotions condition
10. My skin itches 291% Symptoms
14. I tend to do things by myself 275% Functioning because of my skin condition
30. My skin condition makes me tired 264% Functioning
8. I tend to stay at home because of my 263% Functioning skin condition