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

Matthias Augustin Anna K. Langenbruch Mandy Gutknecht Marc A. Radtke Christine Blome 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. - Until the past decade, the evaluation of medical treatment procedures was based almost solely on objective clinicalsomatic outcomes criteria. In the last decade, recording of subjective factors such as the patients experience, behavior, and burden of disease in a standardized and reliable manner intensified, enabling clinicians to characterize the course of disease and the effects of therapy. These factors were summed up in a broad sense under the term quality of life (QoL). In recent years, outcomes data deriving from patients have been named patient reported outcomes (PROs). Today, there is growing consensus among dermatologists and researchers that PROs are essential for the assessment of clinical interventions and care in medicine. From an economic point of view, PROs reflect the value of medical interventions rather than just the output. The most frequently applied concept of PROs in medicine is health-related quality of life (HRQoL). Although many authors have expressed the difficulties of defining QoL (quotation: never try to define quality of life [1]), there is a common sense that HRQoL is a status of wellbeing in emotional, physical, social, and functional dimensions related to health. Accordingly, there is no specific measure of QoL; however, it is necessary to evaluate the well-being of patients in the aforementioned dimensions. For this, the assessment of HRQoL is multidimensional and cannot be differentially evaluated with a single scale. This lack of objective measurement in PRO and QoL evaluation creates some uncertainty from the methodological point of view and considerable unease from the professional perspective, in particular from the doctors. In fact, the inclusion of QoL and other PRO measures is a real paradigm shift from the physician to the patient perspective in medicine. Given the legal, ethical, and social arguments, however, there is no alternative to the measurement of HRQoL in medicine. In addition to the evaluation of the courses of therapy, the evaluation of QoL in dermatology can increase existing knowledge of the psychosocial burdens of those suffering from skin diseases. Moreover, QoL assessment can indicate the necessity of psychosocial and psychotherapeutic measures in an individual patient. In terms of health policy, QoL data can underline the need and justify the costs of dermatologic therapy, even in the absence of a vital treatment indication. In dermatologic health services research, HRQoL is an important outcomes indicator on the performance of the health system [2]. This article summarizes the state of the art of QoL conception, evaluation, and interpretation in dermatology. It provides insight in the numerous instruments developed and evaluated for specific indications in dermatology. If appropriate, the methodological aspects of QoL research are also covered. Based on scientifically sound methodological studies, recommendations are given for the state-of-the-art application of QoL instruments in skin diseases. The aim is to select the most appropriate HRQoL instrument and to find the most reliable interpretation of results. The scope of the article encompasses dermatologic studies, quality management in clinics and practices, health services research, and health economics analyses. This article does not include other PRO concepts such as utilities [3] and the patient-benefit index [4]. Definition of Quality of Life For the specific purpose of this report, a Medline search was conducted November 2011, including the search terms patient reported outcomes, quality of life, patient preferences and willingness to pay. These were cross-referenced with search terms indicating dermatologic disorders in general (e.g. skin diseases) and specific diseases (e.g. psoriasis). The literature search resulted in 25.450 publications relating to patient reported outcomes in dermatology, including 28 % of publications on HRQoL, 25 % on patient satisfaction, 18 % on psychological factors, and 8 % on others (including willingness to pay and patient-benefit index). The most frequently focused dermatologic diseases were chronic inflammatory skin diseases such as psoriasis and atopic eczema (24 % and 22 %, respectively), followed by allergies (16 %) and skin cancer (12 %). The publications included reviews (45 %), case reports or other original publications (25 %), and interventional studies (20 %). The term quality of life is understood very differently in everyday life and in research. Therefore, a prior precise definition of the term is crucial for its scientific use. According to the general scientific notion, QoL is a multidimensional construct that is not directly measured but can only be displayed in its single components [5, 6]. There are differing opinions regarding the areas to be included. Based on a fundamental WHO definition on health, QoL includes the physical, psychological, and social condition of an individual [7]. Several authors point out that QoL encompasses much less the objective availability of material and immaterial things as the degree with which a sp (...truncated)