The negative impact of psoriasis on a patient’s quality of life (QoL) is well documented in the literature. Patients often suffer poor self-esteem, difficulties in social interactions, and significant psychological distress. It is, therefore, critically important that a clinician evaluate the extent to which the disease impacts a patient’s QoL. This chapter reviews several validated and reliable generic, dermatology-specific, and disease-specific QoL instruments useful in measuring the impact of psoriasis on patient’s QoL. These QoL instruments can be especially helpful in identifying those patients who would most benefit from systemic or biologic therapy.
Psoriasis is a chronic, inflammatory dermatologic disease that affects approximately 2% to 3% of the general population. Psoriasis can be cosmetically disfiguring, with much attached social stigmata. Consequently, patients often suffer significant interpersonal and psychologic distress.
The negative impact of psoriasis on a patient’s quality of life (QoL) is well described in the literature. Patients commonly feel embarrassed, self-conscious, or ashamed of their physical appearance. They experience many difficulties in social interactions, especially in meeting new individuals and forming romantic relationships. They frequently demonstrate psychologic problems, including poor self-esteem, frustration, anger, helplessness, anxiety, and depression. Sadly, some patients even develop suicidal ideation.
Beyond its psychosocial effects, psoriasis can cause significant physical complaints, such as severe itching, irritation, and pain. For many patients, psoriasis can be a tremendous burden on their daily lives. In a landmark study published in 1999, Rapp and colleagues found that the negative impact of psoriasis on QoL is comparable with that of other major medical disorders, such as cancer, diabetes, heart disease, and major depressive disorder. Therefore, it has become increasingly clear that psoriasis can have detrimental effects on a patient’s QoL. As such, evaluation of the extent to which the disease impacts a patient’s QoL should be a central aspect of the management and care of patients with psoriasis before initiating therapy and at subsequent visits.
Definition of Q o L
QoL is a broad term used to evaluate the general well-being of an individual. It is meant to encompass all variables that may impact an individual’s life, including physical, social, and psychologic factors. Some authors define QoL as an individual’s perception of his or her position in life, in relation to his or her life goals and belief system. Health-related QoL is a more limited concept used to describe the effects that a disease or its symptoms have on an individual’s life. In terms of psoriasis, health-related QoL consists of physical disabilities (eg, itching, pain, insomnia, difficulty walking); psychologic effects (eg, embarrassment, frustration, anxiety, depression); social effects (eg, making new friends, going to social functions); occupation effects (eg, lost time from work, decreased work productivity); daily burdens (eg, wearing specific clothing to conceal psoriatic plaques, frequently vacuuming); and treatment impact (eg, time demands, cost of therapy, potential side effects).
Importance of Q o L evaluation
There are many reasons why it is especially important to measure the impact of psoriasis on a patient’s QoL. Perhaps the most significant reason is in determining appropriate therapy for psoriasis. Presently, there are several highly effective, systemic therapies for psoriasis, such as cyclosporine, methotrexate. and the biologics including etanercept (Enbrel), adalimumab (Humira), infliximab (Remicade), and ustekinumab (Stelera). There are also many new systemic and biologic therapies currently in development. Unfortunately, all of these systemic therapies carry the potential risk of side effects, including nephrotoxicity, hepatotoxicity, tuberculosis, and malignancy. Thus, when a clinician makes the decision to go beyond topical therapies in the treatment of psoriasis, he or she considers whether the benefits of prescribing systemic therapies outweigh their possible side effects.
In evaluating this risk-to-benefit ratio, the clinician should consider whether the patient’s clinical disease severity and the impact of the disease on the patient’s QoL warrants more aggressive therapy. Generally speaking, a clinician can easily determine a near precise estimate of the clinical disease severity using such measures as the psoriasis area and severity index (PASI) or the psoriasis global assessment scores. However, a clinician may not be accurate in evaluating the impact of the disease on a patient’s QoL. Here, the use of simple QoL instruments can assist the clinician in identifying those patients who would benefit most from systemic or biologic therapy. At the same time, it can provide the clinician with an added means of justifying to third-party payers and other interested parties the need to cover more aggressive, and often more expensive, therapies.
Importance of Q o L evaluation
There are many reasons why it is especially important to measure the impact of psoriasis on a patient’s QoL. Perhaps the most significant reason is in determining appropriate therapy for psoriasis. Presently, there are several highly effective, systemic therapies for psoriasis, such as cyclosporine, methotrexate. and the biologics including etanercept (Enbrel), adalimumab (Humira), infliximab (Remicade), and ustekinumab (Stelera). There are also many new systemic and biologic therapies currently in development. Unfortunately, all of these systemic therapies carry the potential risk of side effects, including nephrotoxicity, hepatotoxicity, tuberculosis, and malignancy. Thus, when a clinician makes the decision to go beyond topical therapies in the treatment of psoriasis, he or she considers whether the benefits of prescribing systemic therapies outweigh their possible side effects.
In evaluating this risk-to-benefit ratio, the clinician should consider whether the patient’s clinical disease severity and the impact of the disease on the patient’s QoL warrants more aggressive therapy. Generally speaking, a clinician can easily determine a near precise estimate of the clinical disease severity using such measures as the psoriasis area and severity index (PASI) or the psoriasis global assessment scores. However, a clinician may not be accurate in evaluating the impact of the disease on a patient’s QoL. Here, the use of simple QoL instruments can assist the clinician in identifying those patients who would benefit most from systemic or biologic therapy. At the same time, it can provide the clinician with an added means of justifying to third-party payers and other interested parties the need to cover more aggressive, and often more expensive, therapies.
Health-related Q o L instruments
Health-related QoL instruments are questionnaires designed to assess the impact of a disease on a patient’s QoL. These QoL instruments can be generic, specialty-specific (ie, dermatology-specific), or disease-specific (ie, psoriasis-specific). Most have been developed for adult patients, but a few have been designed for children. To be a useful QoL instrument, it should demonstrate the following criteria: (1) validity (ie, the instrument evaluates well what it intends to measure); (2) reliability (ie, the instrument is reproducible over time); (3) capable of measuring health-related QoL regardless of the disease severity (ie, the instrument can be used for patients with either mild-to-moderate or moderate-to-severe psoriasis); (4) applicable to a wide variety of patients in different clinical settings; and (5) quick and easy for patients to fill out.
Q o L instruments for psoriasis
Several useful generic, dermatology-specific, and disease-specific QoL instruments exist to evaluate the impact of psoriasis on patient’s QoL. Specifically, generic QoL instruments given to patients with psoriasis include the Short Form 36 (SF-36), the Sickness Impact Profile (SIP), the General Health Questionnaire (GHQ), and the Psychological General Well-Being Index (PGWB). The dermatology-specific QoL instruments commonly administered to patients with psoriasis include the Dermatology Life Quality Index (DLQI), Dermatology Quality of Life Scales (DQoLS), Dermatology Specific Quality of Life (DSQL), and Skindex (Skindex-61, Skindex-29). The dermatology-specific QoL instruments developed for children with psoriasis and other dermatologic disorders are the Children’s Dermatology Life Quality Index (CDLQI) text version and cartoon version. Finally, the psoriasis-specific QoL instruments include Psoriasis Disability Index (PDI), Psoriasis Life Stress Inventory (PLSI), Psoriasis Specific Measure of Quality of Life (PSORIQoL), Salford Psoriasis Index (SPI), and Koo-Menter Psoriasis Instrument (KMPI) ( Box 1 ). Although there may be overlap in the usage of these instruments, the generic instruments are most useful to compare psoriasis with other nonskin diseases, the skin-specific ones to compare psoriasis with other skin conditions, and the psoriasis-specific instrument to use in situations where small changes need to be measured or when psoriasis-specific QoL issues need to be elaborated.
Generic QoL instruments
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Short Form 36
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Sickness Impact Profile
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General Health Questionnaire
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Psychological General Well-Being Index
Dermatology-specific QoL instruments
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Dermatology Life Quality Index
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Dermatology Quality of Life Scales
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Dermatology Specific Quality of Life
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Skindex (Skindex-61, Skindex-29)
Dermatology-specific QoL instruments: children
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Children’s Dermatology Life Quality Index (text version)
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Children’s Dermatology Life Quality Index (cartoon version)
Psoriasis-specific QoL instruments
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Psoriasis Disability Index
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Psoriasis Life Stress Inventory
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Psoriasis Index of Quality of Life
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Salford Psoriasis Index
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Psoriasis Quality of Life 12 items (a part of the Koo-Menter Psoriasis Instrument)
Generic Q o L instruments
Short Form 36
The SF-36 is a 36-question survey that measures eight broad health dimensions: (1) physical functioning, (2) social functioning, (3) role limitations caused by physical problems, (4) role limitations caused by emotional problems, (5) general mental health, (6) energy and fatigue, (7) bodily pain, and (8) general health perception. In addition, there is a question regarding the change in general health in the past year. The SF-36 is scored from 0 (worst health state) to 100 (best health state).
The SF-36 meets stringent criteria of reliability and validity. It has been widely used in more than 200 clinical studies assessing QoL in various medical diseases, including those of the skin. It is considered to be most applicable for comparison of skin diseases with other systemic diseases. In evaluating the impact of psoriasis on QoL, the SF-36 demonstrates significant correlation with PASI scores (ie, worse SF-36 scores are associated with increased psoriasis severity). The SF-36 is also a useful measure of mental health in skin conditions, such as palmoplantar psoriasis, where limited area of skin involvement can cause significant impairment of function. A study of 100 patients with hand eczema recruited from an occupational dermatology clinic reported that the SF-36 was a more suitable measure of health-related QoL compared with the DLQI. This was determined because the study had found that females had more impaired mental health using the SF-36 compared with males but that the DLQI was unable to differentiate the discrepancy in mental health impact between genders.
The SF-36 has been used to compare QoL of patients with psoriasis with the QoL of patients with other chronic health conditions. One study had 317 patients complete the SF-36, and responses were compared with patients who had other chronic conditions including depression, diabetes mellitus type 2, congestive heart failure, myocardial infarction, hypertension, cancer, arthritis, chronic lung disease, and dermatitis. The impact of psoriasis on QoL was determined to be similar to other medical illnesses. The study supported the concept that psoriasis was not simply a cosmetic concern, but it had debilitating physical and emotional effects on patients.
Sickness Impact Profile
The SIP is a measure of health status based on assessment of an individual’s performance on daily activities. The SIP has been used in a broad range of diseases in more than 2000 publications. It has been shown to have high reliability and internal consistency. In psoriasis, the overall SIP scores have been found to correlate well with PDI because both successfully measure the broad extent (in 12 different categories) to which psoriasis limits the patient’s physical and psychosocial functions. This measurement of disability is useful for those patients whose main issue with psoriasis is the functional and physical limitations rather than emotional.
General Health Questionnaire
The GHQ is a survey that identifies patients suffering from diagnosable psychiatric disorders. There are several versions of the GHQ, including the 60-, 30-, 28-, and 12-item versions. The 28-item GHQ consists of four subscales (somatic symptoms, anxiety and insomnia, social dysfunction, and severe depression). The 28-item GHQ is the version typically used on patients with psoriasis, and it has been shown to be highly correlated to psychologic distress specifically in a group of 22 patients with psoriasis undergoing psoralen-ultraviolet light A therapy. In this study, patients were asked to complete a self-rating survey of disease severity, the PDI, and the GHQ. The GHQ, PDI, and patient-rated severity scores all correlated to each other. Overall, the results showed that psoriasis affects mental health through its impact on the daily life of the patient.
Psychologic General Well-Being Index
The PGWB Index is a self-administered, validated psychometric instrument that measures an individual’s emotional well-being. It is specifically designed to be suitable for assessing psychologic well-being of the general medical population as opposed to a psychiatric population. This 22-question instrument can be subdivided into six broad domains (anxiety, depressed mood, positive well-being, self-control, general health, and vitality). PGWB is graded on a five-point Likert-type scale, a psychometric scale commonly used in questionnaires in which answer choices range from “strongly disagree,” “disagree,” “neither agree nor disagree,” “agree,” to “strongly agree.” The PGWB Index is a good tool for assessing the disability of psoriasis. In a study of 32 patients with moderate-to-severe plaque psoriasis receiving adalimumab for 24 weeks, participants were asked to complete the PGWB. Statistically significant improvement in the total PGWB score was documented by Week 4. By Week 24, all six PGWB domains showed statistically significant improvement from the pretreatment baseline. The authors then compared the PGWB scores of patients with psoriasis with those of patients with other chronic medical conditions. Based on PGWB scores, untreated patients with psoriasis have as much impairment in psychologic well-being as patients with other major medical diseases including breast cancer, coronary artery disease, congestive heart failure, and diabetes and that potent intervention improves psychologic well-being to where it is comparable with that of patients with asymptomatic hypertension. A prompt intervention with an effective dermatologic treatment is not only critical, but capable of restoring the physical and psychologic well-being of patients with psoriasis.
Each instrument has a different focus for the measurement of QoL in patients with psoriasis. The SF-36 inquires into the patient’s perception of well-being and his or her attributions of limitations in daily life activities to psoriasis. SF-36 is thus a helpful tool for clinicians to deploy to monitor the effects of psoriasis treatment on the patient’s overall QoL. The SIP includes broad aspects of physical, emotional, and social behavior that suffer impairment as a result of their psoriasis, regardless of clinical symptom severity. SIP thus has a niche in measuring disability of patients with psoriasis and can be used complimentarily with other disability indices, such as the PDI. Furthermore, such tools as the General Health Questionnaire and the Psychological General Well-Being Index are useful in assessing the psychiatric impact of psoriasis on a patient’s QoL. They would not assist a physician who wishes to focus on physical constraints or social disability associated with psoriasis.
Related posts:
Health-Related Quality of Life in Dermatology: Introduction and Overview
Overview of Health Status Quality-of-Life Measures
Quality-of-Life Issues in Vitiligo
Melasma Quality of Life Measures
Clinical Meaning in Skin-specific Quality of Life Instruments: A Comparison of the Dermatology Life Quality Index and Skindex Banding Systems
Future Directions in Dermatology Quality of Life Measures
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