Clinical outcomes

The clinical outcomes measured in rheumatoid arthritis span three broad areas. Firstly, disease measures reflecting the presence and severity of joint inflammation. Secondly, end-organ damage particularly the extent and severity of joint damage. Thirdly, quality of life measures made by patients indicating the impact of their disease on their lives. Some are disease specific such as the Health Assessment Questionnaire (HAQ). Others are generic and applicable across all disease, such as the Short Form 36 (SF-36) and EuroQol. Several new patient-assessed outcome measures have been developed, such as the Patient-Reported Outcome Measurement Information System (PROMIS) and the Rheumatoid Arthritis Impact of Disease (RAID) score. Whether one of these new measures becomes dominant is currently uncertain. Clinical outcomes need to measure what is intended and have face, content, construct, and criterion validity. They also need to discriminate between states of interest reliably, exhibit sensitivity to change, and be easily measured and applied, given constraints of time, money, and interpretability. Different clinical outcomes are closely interrelated. Finally, clinical outcomes such as the EuroQol can be used to generate quality-adjusted life years (QALY), which are used in health economic studies. Measuring disease outcomes is essential for good medical care, which can only improve when clinicians know the results of their treatments and incorporate patients’ views.