Outcome measures, pooled index and quality of life instruments in rheumatoid arthritis

A variety of outcome measures are used in evaluating disease activity and therapeutic efficacy in rheumatoid arthritis (RA) studies, and this makes comparisons of drug efficacy difficult. Some of the endpoints used are not standardized and/or are insensitive to change. The purpose of this report is to present a critical appraisal of outcome measures and quality of life assessments in RA studies.

An overview of the literature was undertaken to determine the extent to which there is consensus among experts in this area of research.

The data suggest that the core set of endpoints in RA clinical studies should include tender joint count swollen joint count, patients' assessment of pain, patients' and physicians' global assessments, patients' assessment of physical function and acute phase reactant level. When trials of disease-modifying antirheumatic drugs (DMARD) last for more than a year, radiography may be useful. A 'pooled index' may be valuable, and its construction is discussed. Quality of life (QoL) instruments facilitate a fuller examination of the effects of health care interventions and these should be used to complement the more traditional clinical endpoints in the core set. The instruments most commonly used in RA research are identified.

We conclude that randomized clinical trials of treatments in RA should now ideally use the core set of clinical endpoints and validated QoL instruments for assessing safety and efficacy.