The Norfolk Arthritis Register (NOAR) was established during 1989. By the beginning of 1990, all the general practitioners in what was then the Norwich Health Authority had been visited and asked to participate. From 1 January 1990, the general practitioners and local rheumatologists referred to NOAR all adults (aged ≥16) whom they saw with two or more swollen joints, lasting for 4 weeks or more, with an onset of symptoms after 1 January 1989.
After receiving a notification, NOAR sends one of its team of metrologists (research nurses) to the patient's home to take a standardised history and to examine the joints for tenderness, swelling and deformity/damage [1
]. In addition, a blood sample is taken for rheumatoid factor (RF) measurement and for DNA extraction. Serum is also stored. The patient completes a Health Assessment Questionnaire (HAQ) [2
] adapted for British use [3
Over 3,500 patients have now been recruited by NOAR. Although the 15 years since NOAR was established have seen dramatic changes in the range of disease-modifying antirheumatic drugs (DMARDS) that are available and the way in which they are used, one of the fundamental questions that NOAR was set up to address remains highly pertinent. This is the question of whether it is possible to predict, early in the course of the disease, a patient's natural history.
This question becomes ever more relevant as it is now well accepted that patients who are destined to have persistent disabling arthritis should start DMARD therapy as soon as possible (preferably within the first 12 weeks of disease). Patients who fail to respond to DMARD therapy should be moved on to a biologic agent. Set against this is the fact that many patients with recent-onset arthritis do well. In some patients, the arthritis resolves completely and many patients never develop any significant disability or radiological erosions. It would be exposing these patients to unnecessary risk to give them intensive DMARD therapy or even biologic therapy. On the other hand, some patients do very badly and fail to respond to one DMARD after another. It would clearly be useful to be able to predict both a poor prognosis and response to individual agents so that the right drug can be given to the right patient – 'designer therapy'.
Predictors (or determinants) of outcome can be grouped into person-specific factors – age, gender, socioeconomic status, lifestyle (e.g. smoking, exercise, alcohol, diet), psychological factors (e.g. coping strategies), genetic make-up – disease-specific factors (e.g. severity of arthritis, comorbidity) and treatment-specific factors (e.g. drug and nondrug modalities, adverse events, patient adherence to prescribed treatment). All these factors interact and the prediction of outcome for the individual patient (as opposed to the average patient) remains problematic.