Assessment of quality of life in rheumatoid arthritis: methods and implications

During the last decade, self-report of health status and quality of life has gained increasing credibility and acceptance in studies of individuals with rheumatoid arthritis (RA). According to a number of reports, the new self-assessment instruments offer an excellent complement to the more traditional clinical outcome measurements. In the absence of a cure for RA and the use of potentially toxic drugs, quality-of-life assessment seems to have an important place in clinical drug trials. The most commonly used quality of life or health status instruments in studies of RA seem to perform well and give reliable and valid information. A common concern, however, with these instruments is that there appears to be a lack of questionnaires which allow satisfaction with various aspects of quality of life to be expressed. Many instruments focus on negative aspects of quality of life, although quality of life for most individuals is related to something positive. There is no perfect instrument applicable for all situations, but the selection of an instrument depends on the specific purpose of a particular study. Psychological interventions are more likely to affect people's emotions and well-being, whereas a drug intervention might more dramatically affect physical function. It appears, however, reasonable to assume that effects of drug intervention on quality of life should be measured with a longer perspective, such as after at least 6 months' observation. The field is still in a phase of methodological and theoretical development which is also reflected in the few numbers of published studies concerning the effect of drug interventions on quality of life of patients with RA.