This study explored the frequency of remaining pain in those with early rheumatoid arthritis (RA) after three months of treatment with methotrexate (Trexall). The results showed that remaining pain was common after treatment. 

RA is a chronic autoimmune disease (when the immune system attacks healthy tissue) that causes pain, stiffness, swelling, and restricted movement in the joints. In early RA, joint inflammation causes high levels of pain. After this has been treated and the inflammation is reduced, it has been noted that patients still have pain. This pain is not related to inflammation and may not be controlled by the drugs used to treat RA. Remaining pain can affect quality of life and work capacity. The frequency and possible reasons for remaining pain after treatment is unclear. 

This study examined the records of 1,241 RA patients treated with methotrexate (MTX) for three months. MTX is typically the first drug used to treat early RA and it is known to be effective. The patients were assessed for pain at the time of diagnosis and then after three months.

40% of patients had a good response to MTX. 29% of this group had remaining pain. 38% had a moderate response to MTX, with 70% of these with remaining pain. 23% had no response to MTX. 83% of this group had remaining pain.

Remaining pain was 2.2 times more likely in those who were more disabled when starting the study. Those with less inflammation prior to treatment and older patients were also more likely to experience remaining pain.

Smoking was associated with an increase in pain.

The study concluded that remaining pain affects almost one third of early RA patients who have responded well to MTX. Levels of disability and inflammation before treatment are associated with remaining pain.

It was not possible to control for depression and anxiety, which are also associated with pain.