Prediction of walking disability by disease-related factors in patients with rheumatoid arthritis.

Objective: To investigate the relationship between disease-related factors and walking disability in different phases of rheumatoid arthritis; and to predict future walking disability in rheumatoid arthritis, using disease-related factors assessed 2 years after diagnosis.

Methods: A cohort of 848 newly diagnosed patients with rheumatoid arthritis was followed up for a maximum of 8 years. Walking disability and several disease-related and demographic factors were recorded during follow-up. A logistic regression model was used to study associations between walking disability and these factors at different time points. A multilevel logistic regression model for longitudinal data was used to predict walking disability during follow-up from potential predictors at year 2.

Results: Global pain and disease activity were consistently related to walking disability at almost every time point. Significant predictors of future walking disability were: walking disability, knee pain, global pain, the passage of time during follow-up, and age.

Conclusion: Global pain and disease activity are related to walking disability during the first 8 years of RA. Walking disability, knee pain, and global pain at 2 years follow-up predict walking disability later in the disease. In addition, the risk for walking disability increases during the disease process and with higher age at diagnosis.