It is difficult to predict how rheumatoid arthritis will develop, because it affects different people in different ways. A study of a large group of people with the condition gave the following results:
* 75 per cent continued having some joint pain, swelling and flare-ups
* 20 per cent always have very mild rheumatoid arthritis
* 5 per cent develop severe disease with extensive disability
Women are three times more likely to be affected than men and the average age is between 35 and 65 for the most frequent cases.