In order to allow personalized medicine, adequate prediction of disease outcome is required. In early undifferentiated arthritis (UA), prediction of the development of RA is crucial, and in case of RA predicting the severity of the disease course may guide individualized treatment decisions.
A total of 570 UA patients and 676 RA patients included in the Leiden Early Arthritis Clinic cohort were studied for baseline characteristics. The disease outcomes studied were fulfillment of the 1987 ACR-RA criteria and arthritis persistence in UA patients and the rate of radiological joint destruction and achieving sustained DMARD-free remission in RA patients.
Predictive factors for fulfillment of the 1987 ACR-RA criteria and for persistent arthritis in UA were largely similar. Risk factors for a severe rate of joint destruction were: older age (P<0.001); male gender (P<0.001); longer symptom duration at first visit (P=0.048), involvement of lower extremities (P<0.001); BMI (P<0.001); high acute phase reactants, presence of IgM-RF (P<0.001); anti-CCP2 antibodies (P<0.001); anti-modified citrullinated vimentin antibodies (P<0.001) and HLA-DRB1 shared epitope alleles (P=0.001). A high BMI was associated with a lower rate of joint destruction but with a higher risk of disease persistence. The proportion of variance in joint destruction explained was 32%
Predictors for RA development, previously used to develop a prediction rule in UA patients, are largely similar to predictors for arthritis persistency. Only part of the joint destruction level in RA is explained by the currently known risk factors. New factors need to be identified in order to guide pharmaceutical intervention at the level of individual RA patients.