Mandy Gutknecht

Quality of Life Measures for Dermatology: Definition, Evaluation, and Interpretation

Patient-reported outcomes (PROs) have gained substantial importance in medical research and care. One of the major areas of PROs is health-related quality of life (HRQoL), which reflects the personal health condition of an individual in physical, social, emotional, and functional dimensions. Other concepts of PROs include a patient’s psychological condition, satisfaction, and preferences. In a general sense, PROs summarize all facts of a medical observation or intervention reported by the patient. In most cases, these outcomes cannot be recorded by other techniques and can only poorly be measured by professionals or relatives (via proxies). This article summarizes the concepts, methodology of measurement, and interpretation of results of PROs in dermatology, with a particular focus on HRQoL. The review is based on a November 2011 literature search and additional scientific exploration by the authors. An updated systematic review on the research terms patient reported outcomes, quality of life, patient preferences, willingness to pay, and PROs was performed. The resulting series of publications were checked for accuracy, topical match, and content. In terms of specific outcomes tools in dermatology, 105 instruments for assessing QoL of dermatology with validated data were identified. With respect to guidelines on QoL measurement in dermatology, three specific guides were found. PROs, in particular QoL and patient preferences, are indispensable constructs in the assessment of the patient perspective in clinical care, clinical research, health services research, and clinical routine. The use of validated methodologies is recommended, and, in most cases, validated instruments are available. Any instrument used should be checked for validity, scientific pureness, and feasibility.

A systematic review on methods used to evaluate patient preferences in psoriasis treatments.

In the treatment of psoriasis and psoriatic arthritis, recently approved medications undergo the ‘early benefit assessment’ in Germany. Psoriasis treatments differ in a multiplicity of characteristics like side‐effects, beneficial effect, cost and process attributes, which serve to evaluate the patient‐relevant benefit compared to standard treatments. Patient preferences might help to aggregate the various patient‐relevant outcomes into a single measure. In this context, besides the calculation of the quality‐adjusted life‐years (QALYs), the Institute for Quality and Efficiency in Health Care (IQWiG) refers to methods of multi‐criteria decision making or preference evaluation like analytic hierarchy process and conjoint analysis. The objective was to give an overview of methods that have been used in international published studies to evaluate patient preferences in psoriasis treatments. The review is based on a systematic literature research on December 2014 in selected electronic databases, using the keywords ‘psoriasis’ and ‘preferences’ as well as the name of specific methods, known from the literature to evaluate patient preferences. The search resulted 389 hits without duplicates. 21 articles met the inclusion criteria. Depending on the study objective, preferences were elicited for health states, health state domains, treatment attributes or treatment alternatives focusing on different outcomes of preferences. Thereby, different methods were used in included studies. For this reason, there is no single outcome available that might be useful in the benefit assessment of the IQWiG. Willingness‐to‐pay, often included as part of a conjoint analysis, was the predominant method to elicit preferences. So far, the analytic hierarchy process has not been used in psoriasis studies. The use of this method in future studies might provide new essential knowledge in the evaluation of patient preferences in psoriasis treatments. However, a clear assignment when to use which method is not given by the IQWiG and should be prioritized.

Assessing the Importance of Treatment Goals in Patients with Psoriasis: Analytic Hierarchy Process vs. Likert Scales

BackgroundTo define treatment benefit, the Patient Benefit Index contains a weighting of patient-relevant treatment goals using the Patient Needs Questionnaire, which includes a 5-point Likert scale ranging from 0 (“not important at all”) to 4 (“very important”). These treatment goals have been assigned to five health dimensions. The importance of each dimension can be derived by averaging the importance ratings on the Likert scales of associated treatment goals.ObjectiveAs the use of a Likert scale does not allow for a relative assessment of importance, the objective of this study was to estimate relative importance weights for health dimensions and associated treatment goals in patients with psoriasis by using the analytic hierarchy process and to compare these weights with the weights resulting from the Patient Needs Questionnaire. Furthermore, patients’ judgments on the difficulty of the methods were investigated.MethodsDimensions of the Patient Benefit Index and their treatment goals were mapped into a hierarchy of criteria and sub-criteria to develop the analytic hierarchy process questionnaire. Adult patients with psoriasis starting a new anti-psoriatic therapy in the outpatient clinic of the Institute for Health Services Research in Dermatology and Nursing at the University Medical Center Hamburg (Germany) were recruited and completed both methods (analytic hierarchy process, Patient Needs Questionnaire). Ratings of treatment goals on the Likert scales (Patient Needs Questionnaire) were summarized within each dimension to assess the importance of the respective health dimension/criterion. Following the analytic hierarchy process approach, consistency in judgments was assessed using a standardized measurement (consistency ratio).ResultsAt the analytic hierarchy process level of criteria, 78 of 140 patients achieved the accepted consistency. Using the analytic hierarchy process, the dimension “improvement of physical functioning” was most important, followed by “improvement of social functioning”. Concerning the Patient Needs Questionnaire results, these dimensions were ranked in second and fifth position, whereas “strengthening of confidence in the therapy and in a possible healing” was ranked most important, which was least important in the analytic hierarchy process ranking. In both methods, “improvement of psychological well-being” and “reduction of impairments due to therapy” were equally ranked in positions three and four. In contrast to this, on the level of sub-criteria, predominantly a similar ranking of treatment goals could be observed between the analytic hierarchy process and the Patient Needs Questionnaire. From the patients’ point of view, the Likert scales (Patient Needs Questionnaire) were easier to complete than the analytic hierarchy process pairwise comparisons.ConclusionsPatients with psoriasis assign different importance to health dimensions and associated treatment goals. In choosing a method to assess the importance of health dimensions and/or treatment goals, it needs to be considered that resulting importance weights may differ in dependence on the used method. However, in this study, observed discrepancies in importance weights of the health dimensions were most likely caused by the different methodological approaches focusing on treatment goals to assess the importance of health dimensions on the one hand (Patient Needs Questionnaire) or directly assessing health dimensions on the other hand (analytic hierarchy process).

Measuring the importance of health domains in psoriasis – discrete choice experiment versus rating scales

Background Psoriasis affects different aspects of health-related quality of life (eg, physical, psychological, and social impairments); these health domains can be of different importance for patients. The importance of domains can be measured with the Patient Benefit Index (PBI). This questionnaire weights the achievement of treatment goals by Likert scales (0, “not important at all” to 4, “very important”) using the Patient Needs Questionnaire (PNQ). Treatment goals assessed with the PBI have been assigned to five health domains; the importance of each domain can be calculated as the average importance of the respective treatment goals. In this study, the PBI approach of deriving importance weights is contrasted to a discrete choice experiment (DCE), in order to determine the importance of health domains in psoriasis, and to find if the resulting weights will differ when derived from these two methods. Methods Adult patients with psoriasis completed both questionnaires (PNQ, DCE). The PBI domains were used as attributes in the DCE with the levels “did not help at all”, “helped moderately”, and “helped a lot”. Results Using DCE, “improving physical functioning” was the most important health domain, followed by “improving psychological well-being”. Using PNQ, these domains were ranked in position two and three following “strengthening confidence in the therapy and in a possible healing”. The latter was least important using DCE. The only agreement of ranking was shown in “reducing impairments due to therapy” (position four). “Improving social functioning” was ranked in position three (DCE) and five (PNQ). Conclusion Health domains have different importance to patients with psoriasis. Using PNQ or DCE to determine the importance of domains results in markedly different rankings; both approaches can thus not be considered equivalent. However, in this study, importance was assessed at the domain level in DCE and at the single item level in PNQ, which may have added to the differences.

Cost-of-illness of psoriasis - results of a German cross-sectional study

Though psoriasis poses a substantial chronic socio‐economic burden, few studies have addressed the economic impact in Germany.

Does the Dermatology Life Quality Index (DLQI) underestimate the disease-specific burden of psoriasis patients?

The Dermatology Life Quality Index (DLQI) is the most frequently used health‐related quality of life (HRQoL) instrument for skin diseases. According to the DLQI instructions, the responses ‘not relevant’ and ‘my skin problem has not at all affected this aspect of life’ (‘not at all’) have to be scored as 0 = no HRQoL impairments.

Health-related quality of life and patient burden in patients with split-thickness skin graft donor site wounds

Split‐thickness skin grafting is a common procedure to treat different kinds of wounds. This systematic, multicentre, observational, cross‐sectional study of adult patients with split‐thickness skin graft (STSG) donor site wounds was conducted to evaluate quality of life (QoL) impairments caused by donor site wounds following split‐thickness skin grafting. Therefore, 112 patients from 12 wound centres in Germany were examined based on patient and physician questionnaires as well as a physical examination of the donor site wound. Most indications for skin grafting were postsurgical treatment (n = 51; 42.5%) and chronic wounds (n = 47; 39.2%). European QoL visual analoque scale (EQ VAS) averaged 64.7 ± 23.3, European QoL 5 dimensions (EQ‐5D) averaged 77.4 ± 30.0.

Disease Burden, Psychological Well-Being and Attitudes regarding the Set of Emergency Medication in Adults with Insect Venom Allergy

Background: Insect venom allergy is common and greatly impairs patients’ quality of life. Additionally, low compliance with carrying emergency medication is reported. The aim of our study was to analyze the disease burden, levels of anxiety and depression, and to evaluate attitudes towards the set of emergency medication in affected patients. Methods: Between April 2016 and January 2017, patients ≥18 years visiting our department because of an insect venom allergy were asked to complete a paper-based questionnaire. The questionnaire assessed willingness to pay (WTP), the Hospital Anxiety and Depression Scale (HADS), subjective anxiety levels, willingness to carry the set of emergency medication, self-assurance in using it, compliance with carrying it, and reasons for not always carrying it. Results: 55 patients (81.8% wasp allergy) were included. On average, WTP for a complete cure was EUR 1,727 (median: 500). Using the HADS, 14.5% showed definite anxiety disorders while 5.5% had significant depression disorders. Most patients stated to carry the emergency medication “always” (25.5%) or “almost always” (47.3%). “Forgetfulness” (36.4%) was reported as the main reason for not always carrying the medication, followed by “too big” (18.2%). Conclusions: In our patient cohort, insect venom allergy was associated with a moderate disease burden and a good compliance with carrying the emergency medication. However, several of our participants demonstrated borderline or significant anxiety and/or depression disorders. In this regard, this study highlights the necessity to regularly ask the patient about the psychological well-being to identify patients needing psychological support.

How to weight patient-relevant treatment goals for assessing treatment benefit in psoriasis: preference elicitation methods vs. rating scales

In psoriasis, several patient-relevant treatment goals must be met to be able to consider a treatment beneficial. To assess treatment benefit, the validated questionnaire Patient Benefit Index (PBI) can be used. Its global score summarizes the degree of patient-relevant treatment goals achieved after treatment, weighted by their individual importance on rating scales. These treatment goals have empirically been assigned to five dimensions. While the weighting procedure of the PBI provides information about the importance patients attach to treatment goals on a rating scale from 0 to 4, methods of preference elicitation provide information on how patients would trade off certain treatment goals against each other. However, since the treatment goals defined in the PBI often overlap conceptually, the dimensions of the PBI might be more suitable for exploration in preference elicitation methods. We used an analytic hierarchy process (AHP) and a discrete choice experiment (DCE) to generate preference-based importance weights for the PBI dimensions, and compared these weights to those derived from the rating scales. We were further interested in the effect of importance weights on the calculation of the PBI score. A total of 120 patients with psoriasis completed a questionnaire at baseline, including AHP, DCE and the rating scales, and at follow-up, regarding the attainment of treatment goals, to calculate the PBI score. In contrast to the results derived from the average rating scores, use of AHP and DCE resulted in both similar importance weights and rankings of dimensions. Presumably, patients rated treatment goals differently than the respective dimension they belong to. However, the differently calculated importance weights led to similar values of the PBI score. Our findings nevertheless provide clear evidence that, regardless of the method used, the importance of treatment goals differs between psoriasis patients, and this should be reflected in treatment decisions.

Cost‐of‐illness of patients with lymphoedema

Chronic lymphoedema is characterized by a continuous need for medical treatment, many comorbidities and impaired quality of life. In Germany, about 4.5 million patients are affected by lymphoedema. Thus, lymphoedema causes high direct and indirect costs, even more in case of complications such as erysipelas and ulcers.