A literature search regarding clinical studies showed an increased number of 154 listings of clinical studies including quality of life parameters20. These papers can be classified according to the patient population or the therapeutic approaches chosen. In addition, they can also be differentiated according to the study objectives and designs ranging from cross sectional over longitudinal studies evaluating the quality of life from before to after a treatment or to randomised clinical trials in which two or more therapeutic arms are compared with each other. Most of the research in the adult clinical trial area has been performed in oncology and cardiology and more recently in psychiatry.
Oncology was one of the first disciplines to approach the topic of quality of life. One reason for this was the question whether the extension of life time for a few months with chemotherapeutic interventions in solid tumours was appropriate if prognosis and expected therapeutic benefit were poor10. From this point, quality of life studies soon evolved around how to improve care for cancer patients. Most research was committed to developing and applying research instruments rather than descriptive clinical studies. Randomized clinical studies were primarily conducted by the large oncological clinical trials groups in North America as well as Europe. In these study groups quality of life has gained an increased consideration as an outcome parameter, e.g. in testing chemotherapy regimens in patients with breast cancer21.
Cardiology was also early to include the topic of quality of life as a study
objective . In contrast to oncology however, specific measurement instruments were not developed but rather existing instruments from public health research were used. Widely discussed was the classical study by Croog et al.23 in which in a cohort of over 500 hypertensive men the superiority of one medication in several of the documented quality of life areas was shown.
Another main area of research in quality of life in clinical trials concerns
coronary heart disease . Most of the clinical studies work with standardized
generic measurement supplemented by a specific questionnaire In general the quality of life indicators for cardiovascular populations show that coronary heart disease is associated with a marked deterioration in quality of
life which seems to be dependent on the NYHA classification, and gender .
In psychiatry, the topic of quality of life research has appeared rather lately, possibly due to a long-standing view that classical psychiatric instruments do already reflect patients' quality of life. The focus, however, was mainly on expert or external ratings of symptomatology; self-reported perception of patients has not been systematically included in psychiatric literature. New approaches to assess quality of life from the patient's point of view are being developed, e.g. in schizophrenia26. In a study with 357 patients suffering from psychiatric disorders, a dramatic decrease in quality of life after disease onset in several relevant dimensions was reported. In neurology, epilepsy as well as stroke have received much attention in terms of adult quality of life research. In epilepsy, development of specific measurement instruments has been performed27. Clinical studies in epilepsy, however, are rare and suggest that anti-epileptic medications with the better side effect profile are associated with better quality of life ratings28. Clinical studies have been reported in other areas as well, e.g. in nephrology, as
concerns the use of erythropoetin in dialysis patients . In pain syndromes, especially headaches, the SF-36 Health Survey was frequently used30. As regards HIV-infections and AIDS, epidemiological studies show that in addition to the severity of disease unfavourable living conditions and financial problems contribute to a decreased quality of life in HIV-infected and AIDS-patients31, and treatment with erythropoetin showed positive effects on quality of life in 251 anaemic patients with HIV-infection32. In Surgery, most studies relating to quality of life are available in gastrointestinal surgery, e.g. pouch reconstruction or in limp surgery hip
In clinical application, the quality of life studies have followed a certain pattern. As a first step, theoretical and conceptual articles about quality of life assessment have been published followed by methodological work on the development of new assessment instruments or the use of available ones. Cross-sectional and longitudinal observational studies have followed to assess the quality of life impairments in specific patient populations which is dramatic according to a recent literature review and also demonstrates marked difference from the medical criteria. Only in few disease areas, clinical trials have been conducted. Most successful were approaches in which multinational clinical study groups have joined efforts to produce state of the art study protocols to include quality of life assessment in clinical trials. New developments in quality of life research pertain to the health sciences in which quality of life is a new health status indicator in public health studies (e.g. for evaluating the effect of preventive programs). Also, in health economy the use of quality of life instruments has to be more critically discussed. Lately, publications have compared the psychometric quality of different measurement instruments for a specific disease.
What does this mean concerning Adamantiades-Behçet's disease? It is basically the necessity to develop appropriate instruments. Also, implementing quality of life outcomes in a epidemiological, clinical and health-economic study is recommended.
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