Quality of life assessment in skin disease

QoL is defined by WHO as 'individuals' perceptions of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns'.¹ It is increasingly understood as critically important to our management of patients with dermatological disease.

Health-related QoL is the patient's assessment of the effect of their skin disease and treatment on their physical, psychological and social position, and their overall wellbeing.

In chronic skin disease, such as psoriasis and atopic dermatitis, where treatments may only offer partial remission or a temporary measure, the subjective assessment of how a patient's life is affected by their skin disease is crucial to the dermatologist's management strategy.

This not only de-medicalises the problem, but also gives the clinician a deeper insight into the patient's overall health. Such assessments also empower patients, by giving them a role in the decision-making process for their clinical management. The clinician's aim is to treat patients holistically. Skin diseases can be debilitating to patients in many ways, including those listed in box 1.

There are a variety of tools at clinicians' disposal to facilitate the recognition of this impact, including general health-related, dermatology-specific and dermatological disease-specific QoL measures. These tools are used increasingly in healthcare management, in the clinical trial research setting and in everyday clinical use.

Generic QoL tools

Generic tools to assess QoL have the advantage of applying to a variety of diseases, spanning all medical specialties. One example is the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36).²

However, generic tools may not highlight what is significantly debilitating for a patient with a dermatological disease, because they are not specific to dermatology.

For example, SF-36 has no question about which items of clothing a patient with a skin condition is able to wear without discomfort,2 but this important question is included in the Dermatology Life Quality Index (DLQI),³ a more specific QoL instrument for dermatology.

Dermatology-specific tools

The DLQI3 is one of the most well-known dermatology-specific QoL instruments, consisting of 10 questions to be interpreted under six headings - symptoms and feelings, daily activities, leisure, work and school, personal relationships and treatment.

It has been used in more than 40 skin diseases and is the most frequently used QoL questionnaire in clinical trials.

Scores range from zero to 30. Scores of six to 10 represent a moderate effect on the patient's life, 11-20, a very large effect and 21-30, an extremely large effect.

In general, for patients with inflammatory skin conditions, a change in score of at least four points is considered clinically significant. This represents a meaningful change in the patient's QoL compared with their previous assessment.⁴

In theory, clinicians should be able to compare the results of dermatology-specific instruments between chronic skin diseases. However, these should be interpreted with caution because patients with different skin conditions may answer these questions differently.⁵

Dermatological disease-specific tools

One example of a dermatological disease-specific QoL tool is the Psoriasis Disability Index (PDI).⁶ This questionnaire consists of 15 items and is tailored to psoriasis – for example, question 15 asks: 'To what extent has your psoriasis or treatment made your house messy or untidy?' and for patients undergoing coal-tar based treatments, this is particularly pertinent.⁷

Disease-specific instruments can detect more specific aspects in relation to health-related QoL or disability because they give better insight into the particular patterns of a skin disease.

These scales (see box 2)^5,8 can be used not only to assess QoL, but also to measure the effect of treatment, in terms of reduction in the disability being caused by the skin disease.

Assessing impact on the patient's family

A new use of health-related QoL measures in atopic dermatitis and eczema is in measurement of the impact on the patient's family, which can provide evidence to be used in negotiating increased resources for family care.

As an example, the Dermatitis Family Impact (DFI) questionnaire asks how a child's eczema has affected food preparation and meals for the family.⁹ Other aspects of family life that appear in this questionnaire include emotional distress, physical wellbeing, personal relationships, other people's reactions, social life, recreation and leisure activities, time assisting therapy, housework, work and study, and expenditure.

Acne can have a profound effect on an adolescent's QoL (Photograph: Dr Zara/BSIP/Science Photo Library)

Children and adolescents

The Children's Dermatology Life Quality Index (CDLQI)¹⁰ is for use in children aged four to 16 years, and has been used in the assessment of 14 skin conditions.¹¹

This dermatology-specific questionnaire for children covers symptoms, embarrassment, friendships, clothes, playing, sports, school and holiday activities, teasing, sleep and treatment. Similar to the DLQI, scores range from zero to 30. Scores of seven to 12 represent a moderate effect on the child's life, 13-18, a very large effect and 19-30, an extremely large effect.¹²

There is currently no specific adolescent health-related QoL tool,¹³ so the standard DLQI is used in adolescents aged over 16 years. A physical condition that is visible to others can have a profound effect on an adolescent's QoL during this time of sexual and emotional development. There is a clear need for an adolescent-specific QoL questionnaire to be devised.

Assessment and management

If the patient scores highly in a health-related QoL questionnaire, concurrent psychiatric conditions, such as agoraphobia, social anxiety disorder, body dysmorphic disorder and depression, should be considered.

Treatment can involve CBT and SSRIs. When assessing a patient with psoriasis, the clinician carries out a Psoriasis Area and Severity Index (PASI) rating, a quantitative score to assess the severity of psoriatic lesions, and the patient completes a DLQI score.

A patient may have a low PASI score and a very high DLQI score, showing that objectively mild disease can significantly affect the perception of QoL.

National guidance on the management of patients with psoriasis¹⁴ recommends the use of either the DLQI or the CDLQI, depending on the patient's age, for assessment and management. These questionnaires are used to assess the patient's physical, psychological and social wellbeing, as a way of assessing response to treatment.

A minimum DLQI score of 10 is used as a criterion for commencing the patient on adalimumab, etanercept or ustekinumab, while a score of more than 18 is a criterion for infliximab. The measurement of change in DLQI score from baseline is used to assess response to biological and systemic agents.¹⁴ It is likely that health-related QoL questionnaires will be increasingly used in other areas of dermatology in future.

The European Academy of Dermatology and Venereology Taskforce has acknowledged the number of different tools that are available to measure QoL and recommends the use of both generic and dermatology-specific questionnaires in the clinical research setting, but only dermatology-specific questionnaires in the clinical setting.

It has justified this decision by recognising that generic instruments may overlook vital dermatology-specific measures. The taskforce has also welcomed further research in the form of methodological studies of the comparison of patient-reported outcomes.⁵ This will help clinicians gain a better understanding of the evidence base behind their use.

The visible nature of dermatological conditions means that there is often a hidden psychosocial impact for patients, which makes the use of health-related QoL even more important in their management.

However, health-related QoL instruments are an adjunct to, not a substitute for, a good doctor/patient relationship, where the patient is assessed holistically and can offer insight into their management, working collaboratively with the clinician.

• Dr Claire Marshall is a clinical research fellow in dermatology and Dr Anthony Bewley is a consultant dermatologist at Whipps Cross University Hospital, Barts Health NHS Trust, London

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Main photo: ISM/Science Photo Library

References

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14. NICE. Psoriasis: the assessment and management of psoriasis. CG153. London, NICE, October 2012.