Psychometric properties of the Chinese version of Dermatology Life Quality Index (DLQI) in 851 Chinese patients with psoriasis

Higher-order sensorimotor circuit of the whole-brain functional network involved in pruritus regulation in atopic dermatitis

BACKGROUND

Little is known about the neural mechanisms underlying pruritus regulation in Atopic dermatitis (AD).

OBJECTIVE

To investigate the functional changes of the resting-state whole brain network of AD participants and the mechanisms by which they were involved in pruritus regulation.

METHOD

Based on the functional magnetic resonance imaging data from 19 AD participants and 37 healthy controls (HC), a graph-theoretical measure of degree centrality (DC) conjoined with a voxel-level seed-based functional connectivity (FC) method was used to identify abnormal higher-order nodes and the functionally relevant circuit in AD participants compared to healthy controls (HC).

RESULTS

Of 64 participants screened, 19 AD participants (12M/7F, median [IQR] age, 27 [14] years) and 36 HCs (13M/23F, median [IQR] age, 20 [1] years) were enrolled. DC values of the left superior frontal gyrus (LSFG) increased in AD participants and exhibited a negative correlation with the SCORAD score (r = -0.561, p = 0.012) compared with HC. In the FC analysis with LSFG as the seed, FC values of several sensory and motor regions increased in AD participants, highly overlapping with the anatomical distribution of the inferior fronto-occipital fascicle (IFOF). AD participants with severe pruritus exhibited lower levels of DC (T = -2.316, p = 0.033) and FC between the LSFG and left insula (T = -2.203, p = 0.042) than those with mild-to- moderate pruritus.

CONCLUSIONS AND RELEVANCE

LSFG was involved in pruritus regulation in AD by forming a high-order sensorimotor circuit through the IFOF, a white matter fascicle that proved to provide multimodal integration in motor control and sensory information processing. These results offer more mechanism-guided treatment targets for severe pruritus in AD.

Psoriatic Foot Involvement is the Most Significant Contributor to the Inconsistency Between PASI and DLQI: A Retrospective Study from China

Background

The Psoriasis Area and Severity Index (PASI) and the Dermatology Life Quality Index (DLQI) are important evaluation tools for assessing psoriasis severity and guiding treatment options. However, the scores of PASI and DLQI are often inconsistent.

Objective

This study aimed to identify the factors affecting the consistency between PASI and DLQI.

Methods

The retrospective study was based on 4125 patients. We collected the PASI, DLQI, demographic and clinical characteristics data.

Results

DLQI has a weak correlation with PASI (r=0.37; P<0.001). For the DLQI >10 groups, DLQI has almost no correlation with PASI (r=0.16; P<0.001). There are 43.60% of mild-to-moderate patients (PASI<10) in the DLQI>10 groups. Our adjusted model showed that foot (OR=2.109; 95% CI:1.581-2.815) involvement led to the greatest impairment of QoL except for PASI≥10 (OR=5.547; 95% CI:3.477-8.845). Furthermore, DLQI impairment was associated with female (OR=1.336; 95% CI:1.071-1.667); the age of 20-39 subgroup (OR=1.795; 95% CI:1.100-2.930); psoriatic arthritis (OR=1.718; 95% CI:1.208-2.443); higher income (OR = 1.408; 95% CI: 1.067-1.858); family history of psoriasis (OR=1.460; 95% CI:1.131-1.885). Moreover, the influence of exposed lesions (such as scalp; face; neck; nails; and hands) were positively associated with severely impaired QoL.

Conclusion

Dermatologists should recognize the underestimated disease burden of psoriasis patients and actively identify and treat mild-to-moderate patients with high burden. In particular, the foot was a significant contributor to the burden.

Patient-Reported Outcome Measures and Their Clinical Applications in Dermatology

With more disease- and symptom-specific measures available and research pointing to increased usefulness, patient-reported outcome measures (PROMs) can be routinely used in clinical care. PROMs increase efficiency in healthcare, improve the clinician-patient relationship, and increase patient satisfaction with their care. PROMs can be administered before, during, and after clinic visits using paper-and-pencil, mobile phones, tablets, and computers. Herein, we combine available literature with expert views to discuss overcoming barriers and helping dermatologists incorporate PROMs into routine patient-centered care. We believe dermatology patients will benefit from broader PROM implementation and routine clinical use. However, a few major barriers exist: (1) cost to implement the technology, (2) selecting the right PROMs for each disease, and (3) helping both patients and clinicians understand how PROMs add to and complement their current clinical experience. We provide recommendations to assist dermatologists when considering whether to implement PROMs in their practices.

Health Related Quality of Life of Rosacea Patients in China Assessed by Dermatology Life Quality Index and Willingness to Pay

PURPOSE

Rosacea is a chronic inflammatory dermatosis mainly involving facial skin, leading to physical and emotional problems, which greatly affect the quality of life (QoL) of patients. Dermatology Life Quality Index (DLQI) and willingness to pay (WTP) are well-established instruments assessing the health-related quality of life (HRQoL), while very few studies have been focused on this topic about rosacea in China. The present study investigated HRQoL in Chinese rosacea patients.

PATIENTS AND METHODS

This cross-sectional study was conducted on 973 patients with rosacea. Sociodemographic data, clinical features and DLQI were collected, and WTP was assessed by three standardized items. Multivariable logistic analysis was performed to investigate independent factors influencing QoL.

RESULTS

A total of 921 questionnaires were accomplished by participants. The mean DLQI score was 11.6 (median 11). Patients were willing to pay an average of € 896.2 (median € 368.1) for complete cure. 33.3% would like to pay more than 20% of their monthly income to achieve sustainable control. There were positive correlations between WTP with DLQI (P < 0.05). DLQI could be independently impacted by age (21-30 and 31-40 relative to > 50, OR = 3.242 and 3.617, respectively), the occupational requirement of appearance (high, OR = 4.410), disease duration (< 2 years, OR = 1.582), edema (OR = 1.844) and severity of flushing, burning, stinging and pruritus (severe, OR = 2.003, 1.981, 2.491, 2.249, respectively). There were no significant associations between WTP and most of the clinical factors.

CONCLUSION

The QoL was greatly impaired and should not be ignored among rosacea patients in China. Patients aged 21-40y, having occupational requirement of appearance, with the disease duration less than 2 years, and suffering severe flushing and related sensitive symptoms were more likely to have severe or very severe limitation of QoL.

Frequency and influence of "not relevant" responses on the Dermatology Life Quality Index among adults with atopic dermatitis

PURPOSE

"Not relevant" responses (NRRs) on the Dermatology Life Quality Index (DLQI) are common among adults with psoriasis and may be associated with underestimation of disease burden. Little is known about "not relevant" responses among adults with atopic dermatitis. We aimed to examine the frequency of NRRs on the DLQI and to determine whether NRRs are associated with underestimation of disease burden among adults with atopic dermatitis.

METHODS

Adults with atopic dermatitis were identified and evaluated via online survey. We evaluated the frequency of NRRs on the DLQI, stratified by sociodemographic characteristics. To examine the association between NRRs and other measures of disease burden, Patient-Oriented Eczema Measure (POEM), Patient-Oriented SCORAD (PO-SCORAD), and Short-Form (SF)-12 scores were compared between those who responded "not relevant" versus "not at all".

RESULTS

Among 764 adults with atopic dermatitis, most had mild disease. The median (interquartile range [IQR]) POEM, PO-SCORAD, and DLQI scores were 5 (2-10), 24 (14-34), and 2 (1-6), respectively. Most (55.2%) also had at least one NRR, and 17.9% had 4 or more "not relevant" responses, with differences across several sociodemographic characteristics. There were no substantial differences in SF-12, POEM, and PO-SCORAD scores between those who responded "not relevant" versus "not at all".

CONCLUSION

NRRs on the DLQI are common among adults with atopic dermatitis and differ across sociodemographic characteristics, suggesting issues with content validity. There is not a clear association between NRRs and other measures of disease severity among adults with mostly mild atopic dermatitis.

Development and Evaluation of the Psychosocial Adaptation Questionnaire among Patients with Chronic Skin Disease

BACKGROUND/OBJECTIVE

Chronic skin disease (CSD) often has physiological, psychological, and social impacts, which requires the patient to adjust to achieve psychosocial adaptation (PSA). As a standardized assessment instrument was lacking, we developed a PSA questionnaire for patients with CSD (PSAQ-CSD).

METHODS

According to the steps of questionnaire development, a systematic process of scoping review, qualitative research, content validity expert review, testing in a sample of 321 adults, item analysis, and classical test theory methods were applied.

RESULTS

Following item analysis and exploratory factor analyses, 18 items were eventually entered into the model of confirmatory factor analyses, with a cumulative contribution of 65.435%. Three subscales were developed: emotional, self-cognitive, and social dimensions. Item analysis, exploratory factor analyses, and content validity expert review narrowed the subscales to 8, 6, and 4 items, respectively.

CONCLUSIONS

The 18-item PSAQ-CSD has been confirmed to have good internal consistency reliability and convergent and discriminant validity. It may be a useful tool to evaluate the PSA among patients with CSD and provide a basis for further research.

Treatment Outcome Measurement Instruments for Port Wine Stains: A Systematic Review of Their Measurement Properties

BACKGROUND

A plethora of outcome measurement instruments (OMIs) are being used in port wine stain (PWS) studies. It is currently unclear how valid, responsive, and reliable these are.

OBJECTIVES

The aim of this systematic review was to appraise the content validity and other measurement properties of OMIs for PWS treatment to identify the most appropriate instruments and future research priorities.

METHODS

This study was performed using the updated Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN) methodology and adhered to PRISMA guidelines. Comprehensive searches in Medline and Embase were performed. Studies in which an OMI for PWS patients was developed or its measurement properties were evaluated were included. Two investigators independently extracted data and assessed the quality of included studies and instruments to perform qualitative synthesis of the evidence.

RESULTS

In total, 1,034 articles were screened, and 77 full-text articles were reviewed. A total of 8 studies were included that reported on 6 physician-reported OMIs of clinical improvement and 6 parent- or patient-reported OMIs of life impact, of which 3 for health-related quality of life and 1 for perceived stigmatization. Overall, the quality of OMI development was inadequate (63%) or doubtful (37%). Each instrument has undergone a very limited evaluation in PWS patients. No content validity studies were performed. The quality of evidence for content validity was very low (78%), low (15%), or moderate (7%), with sufficient comprehensibility, mostly sufficient comprehensiveness, and mixed relevance. No studies on responsiveness, minimal important change, and cross-cultural validity were retrieved. There was moderate- to very low-quality evidence for sufficient inter-rater reliability for some clinical PWS OMIs. Internal consistency and measurement error were indeterminate in all studies.

CONCLUSIONS

There was insufficient evidence to properly guide outcome selection. Additional assessment of the measurement properties of OMIs is needed, preferentially guided by a core domain set tailored to PWS.

Dimensionality and psychometric analysis of DLQI in a Brazilian population

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.

Assessment of the Dermatology Life Quality Index (DLQI) in a homogeneous population under lifetime arsenic exposure

PURPOSE

The psychometric property of the Dermatology Life Quality Index (DLQI) is underappreciated in public health settings. Our study aimed to assess the reliability, validity, and measurement invariance of DLQI in a homogeneous population with arsenic-related skin lesions and symptoms.

METHODS

A cross-sectional study was conducted in communities under lifetime arsenic exposure. The DLQI was measured through a face-to-face interview. Skin examinations were performed by certificated dermatologists. The intensity of itching was measured by a numerical rating scale. Reliability, structural validity, and measurement invariance were determined using classical and modern test theories, including confirmatory factor analysis and item response models.

RESULTS

465 participants with arsenic-related skin lesions and symptoms completed the DLQI assessment. The Cronbach's alpha was 0.79, and the split-half reliability was 0.77. A two-factor model exhibited the best model fit among models evaluated, but local dependencies among items were identified. The model showed good root mean square error of approximation (0.031) and acceptable Tucker-Lewis index (0.92). Multi-group confirmatory factor analysis showed no measurement invariance across subgroups of age, gender, ethnicity, and intensity of itching.

CONCLUSIONS

The DLQI had acceptable psychometric properties, but measurement invariance was not observed across different groups of participants.

Management of skin toxicity caused by epidermal growth factor receptor inhibitors: an evidence-based implementation project

BACKGROUND

Epidermal growth factor receptor inhibitors (EGFRIs) bind to and inhibit epidermal growth factor receptors (EGFRs) in cancer cells, slowing/preventing tumor growth. As a type of "targeted therapy", they have demonstrated therapeutic effects on solid tumors including colorectal, lung, and head and neck cancers. While effective, various skin reactions are associated with EGFRI therapy which can lead to dose modification or discontinuation as well as discomfort, pain and reduced quality of life. With adequate knowledge and skills, EGFRI-induced skin toxicity can be effectively managed collaboratively by clinicians and people affected by cancer.

OBJECTIVES

This project aimed to improve management of skin toxicity caused by EGFRIs by implementing evidence-informed practice within a chemotherapy department.

METHODS

Evidence-informed recommendations for practice and corresponding audit criteria were developed based on a series of literature reviews. Current practice was reviewed against these criteria with 19 nurses and 21 patients within a chemotherapy department. Barriers to adherence to evidence-informed practice were identified and strategies to improve compliance were implemented with clinicians and patients. A follow-up audit against the criteria was used to measure changes in clinical practice.

RESULTS

Multiple strategies for getting research into practice appear to have been successful. The follow-up audit demonstrated large improvements in compliance across all audit criteria in comparison with baseline results with all but one criterion achieving 100% compliance. Low rates of suspected infection meant that clinical practice could not be measured for criterion 7.

CONCLUSIONS

Auditing current practice and implementation of strategies to improve compliance with evidence-informed practice were effective. Sustaining these improvements is vital to ensure clinical practice continues to support better patient outcomes.

Analysis of quality of life and influencing factors in 197 Chinese patients with port-wine stains

Port-wine stains (PWS) are congenital capillary malformations, usually occurring on the face, neck, and other exposed parts of the skin, that have serious psychological and social impact on the patient. Most researchers focus on the treatment of PWS, but the quality of life (QoL) of PWS patients is seldom researched. The objective of this study is to evaluate the QoL of patients with PWS on exposed parts and explore the factors influencing the QoL of PWS patients. The QoL of 197 cases with PWS on exposed parts were prospectively studied using the Dermatology Life Quality Index questionnaire (DLQI), and the factors influencing the patients' QoL were analyzed by single-factor analysis and multiple-factor logistic regression analysis. The reliability and validity of the QoL of PWS patients were then assessed by DLQI. A total of 197 valid questionnaires were collected. The DLQI scores in PWS cases ranged from 2 to 16, with 2 to 5 in 52.29% (103/197), 6 to 10 in 42.13% (83/197), and 11 to 20 in 5.58% (11/197). The main score elements of the DLQI focused on symptoms and feelings, daily activities, and social entertainment. Single-factor analysis and multiple-factor logistic regression analysis showed that the main influencing factors were female sex, skin hypertrophy, and lesion area >30 cm. The inter-item correlation averaged 47.46% and the Cronbach α was 0.740, indicating high internal consistency. Correlation of the 6 dimensions of the DLQI questionnaires with the total scores showed that the Spearman correlation coefficient r ranged from 0.550 to 0.782 (P < .001), with symptoms and feelings having a correlation coefficient of 0.782 and a high correlation with total scores. This study shows that PWS has mild to moderate influence on the QoL of most patients, mainly on daily activities, social entertainment, and feelings.

A detailed analysis of 'not relevant' responses on the DLQI in psoriasis: potential biases in treatment decisions

BACKGROUND

Dermatology Life Quality Index (DLQI) is the most common health-related quality of life measure in dermatology that is widely used in treatment guidelines for psoriasis. Eight of the 10 questions of the DLQI offer a 'not relevant' response (NRR) option that is scored as the item had no impact on patients' life at all.

OBJECTIVE

To explore the occurrence of NRRs on the DLQI in psoriasis patients and to examine the effect of several socio-demographic and clinical factors on giving NRRs.

METHODS

Data were obtained from two cross-sectional surveys among psoriasis patients at two academic dermatology clinics in Hungary. Health-related quality of life was measured by employing DLQI and EQ-5D-3L, while disease severity was graded by Psoriasis Area and Severity Index (PASI). Multivariate logistic regression was applied to determine the predictors of providing NRRs.

RESULTS

Mean age of the 428 patients was 49 years, and 65% were males. Mean PASI, DLQI and EQ-5D-3L index scores were 8.4 ± 9.5, 6.8 ± 7.4 and 0.74 ± 0.28, respectively. Overall, 38.8% of the patients had at least one NRR: 19.6% (one), 11.5% (two), 5.1% (three) and 2.6% (more than three). Most NRRs occurred in sport, sexual difficulties and working/studying items of the DLQI (28.4%, 16.4% and 14.0%, respectively). Female gender (OR 1.65; 95% CI 1.04-2.61), older age (OR 1.05; 95% CI 1.03-1.07) and higher PASI score (OR 1.03; 95% CI 1.01-1.06) were associated with providing more NRRs, whereas highly educated patients (OR 0.34; 95% CI 0.16-0.72) and those with a full-time job (OR 0.47; 95% CI 0.29-0.77) less frequently tended to tick NRRs.

CONCLUSION

The high rate of psoriasis patients with NRRs, especially among women, less educated and elderly patients, indicates a content validity problem of the measure. A reconsideration of the use of the DLQI for medical and financial decision-making in psoriasis patients is suggested.

Rasch analysis holds no brief for the use of the Dermatology Life Quality Index (DLQI) in Chinese neurodermatitis patients

BACKGROUND

The Dermatology Life Quality Index (DLQI) is the most widely used measure of health-related quality of life (HRQoL) associated with skin disease. Recently, the psychometric properties of the DLQI have caused some controversy because the instrument appears not to meet the requirements of modern test theory. The purpose of this study was to assess whether these psychometric issues also occur in Chinese patients with neurodermatitis.

METHODS

One hundred fifty consecutive outpatients (83 males and 67 females) seeking treatment for neurodermatitis were assessed for eligibility for this prospective study between July 1, 2011 and September 30, 2011. The DLQI and a demographic questionnaire were completed. One female participant who incompletely answered the DLQI was excluded. Data were analyzed using the Rasch model in order to obtain meaningful scores for the DLQI. Scale assessment included analysis of rating scale function, item fit to the Rasch model, aspects of person-response validity, unidimensionality, person-separation reliability, and differential item function.

RESULTS

The rating scale advanced monotonically for all items in the DLQI, but item 9 did not demonstrate acceptable goodness-of-fit (Infit MnSq values >1.3) to the Rasch model. The 10 items of the DLQI met the criteria for person-separation reliability (PSI = 2.38) and the first latent dimension (general QoL) accounted for 50.8 % of the variance; but the variance explained by the second dimension (7.1 %) exceeded the criterion of 5 %. There were also limitations related to person-response validity, because ≥ 5 % (18.1 %) of cases demonstrated unacceptable fit. There was no uniform differential item functioning.

CONCLUSIONS

For neurodermatitis patients, the DLQI seems to have poor fit to the Rasch model; therefore, we recommend against using this instrument with neurodermatitis patients.

Reliability and validity assessment of the revised Symptom Checklist 90 for alopecia areata patients in China

No study has tested the reliability and validity of the revised Symptom Checklist 90 (SCL-90-R) for patients with alopecia areata (AA), and few have used it to evaluate the mental health of AA patients. To assess the psychological status in Chinese AA patients using the SCL-90-R, and to evaluate its reliability and validity, the psychological status of 168 patients and 100 controls was evaluated with the Chinese-version SCL-90-R. From this study, we found that The Global Severity Index and nine subscale scores on the SCL-90-R were significantly higher in AA patients than that in the controls. Moreover, The Global Severity Index and nine subscale scores on the SCL-90-R were associated with disease duration, age of onset, sex and type of AA. In addition, the SCL-90-R presented good internal consistency (whole scale α = 0.98 and split-half coefficient = 0.95). The intercorrelations between the nine subscales and their correlations with the total scale were 0.58-0.93. Factor analysis produced 22 factors with eigenvalues more than 1.0; the first factor explained 33.88% of the variance. Only hostility and paranoid ideation merged into one factor. Taken together, our data indicated that Chinese AA patients demonstrate greater psychopathology than healthy controls. The SCL-90-R can be used to assess global psychological distress in AA patients with good reliability and validity.

Development and psychometric validation of the Chinese version of Skindex-29 and Skindex-16

Background

Dermatological disease significantly affects patient’s health-related quality of life (HrQoL). Skindex is one of the most frequently used dermatology-specific HrQoL measures. Currently no Chinese version of Skindex is available. The aim of this study was to translate and culturally adapt Skindex-29 and Skindex-16 into Chinese, and to evaluate their reliability and validity.

Methods

Translation and cultural adaption were performed following guidelines for cross-cultural adaption of health-related quality of life measures. Subsequently, a cross-sectional study was conducted in which patients with dermatological disease (n = 225) were enrolled. The Chinese version of Skindex-29 and Skindex-16 and Dermatology Life Quality Index (DLQI) were completed. Reliability was evaluated with internal consistency using Cronbach’s alpha. Validity was evaluated using known-groups validity, convergent validity and factor structure validity.

Results

There were both seven items of Skindex-29 and Skindex-16 requiring a second forward- and backward- translation to achieve the final satisfactory Chinese version. The internal consistency reliability was high (range of Cronbach’s alpha for the scales of Skindex-29 0.85-0.97, Skindex-16 0.86-0.96). Known-group validity was demonstrated by higher scores from patients with inflammatory dermatosis than from patients with isolated skin lesions (P < 0.05). Evidence of factor structure validity of the Skindex-29 and Skindex-16 was demonstrated by both exploratory factor analysis that accounted for 68.66% and 77.78% of the total variance, respectively, and confirmatory factor analysis with acceptable fitness into the expected three-factor structure.

Conclusion

This study has developed semantically equivalent translations of Skindex-29 and Skindex-16 into Chinese. The evaluation of the instruments’ psychometric properties shows they have substantial evidence of reliability and validity for use as HrQoL instruments in Chinese patients with dermatological disease.

Reliability and validity of the Chinese version of the Psoriasis Disability Index (PDI) in Chinese patients with psoriasis

Background

The Psoriasis Disability Index (PDI) is a widely used instrument to measure the impact of psoriasis on patients. There has not been psychometric evaluation of the Chinese version of PDI. The aim of this study was to evaluate its reliability and validity among Chinese patients with psoriasis.

Methods

A multi-center, cross-sectional study was conducted at 9 hospitals including patients aged 18 years and over. Reliability was determined by internal consistency using Cronbach’s alpha. Validity was assessed through convergent validity and known groups validity. Dimensionality of the PDI was examined by exploratory factor analysis in working patients and nonworking patients respectively.

Results

In all, 831 patients were studied. Internal consistency of the PDI was satisfactory. Cronbach’s alpha coefficient was 0.91 for the total score and over 0.70 for each subscale of the PDI. Evidence of convergent validity of the PDI was proved by excellent and moderate to good correlations with the Dermatology Life Quality Index (DLQI) and four subscales of the Short Form-36 (SF-36) (role-physical, bodily pain, social functioning, and role-emotional): r = 0.51-0.78. Known groups validity was confirmed that the PDI score discriminated well among patients with different severity of psoriasis. The dimensionality of the PDI was determined by the presence of two-factor structure for working patients and three-factor structure for nonworking patients which accounted for 57.3% and 62.3% of the variance respectively.

Conclusion

The Chinese version of the PDI is a reliable and valid instrument to assess the impact of psoriasis on patients’ lives and could be used in future quality of life assessment of Chinese patients with psoriasis.