Being overweight reduces the chance of early remission in rheumatoid arthritis

news New research has shown that people who are overweight or obese are much less likely than people with a normal body weight to achieve early and sustained remission of their arthritis.

Rheumatoid arthritis is a type of arthritis which happens when the immune system which normally protects us from infections, instead starts to attack the joints causing inflammation. This can cause pain, stiffness and swelling in the joints and if untreated can lead to severe joint damage and sometimes disability. Rheumatoid arthritis is also a “systemic” illness, meaning that it can cause people to feel tired and unwell and if the arthritis is active or inadequately treated, it can significantly increase the risk of cardiovascular disease (heart attacks and stroke) and certain types of cancer.

Remission usually means minimal or no swelling or tenderness in the joints and normal levels for a blood test that measures the level of inflammation in the body. The faster that remission of arthritis is achieved, the less the future joint damage and the better the long-term outcome for the person with arthritis.

Therefore, the aim of most rheumatologists and other healthcare professionals who treat people with rheumatoid arthritis should be to treat the condition as soon as possible, aiming to minimise the risk of joint damage and disability and to reduce the other risks to health, thereby achieving early remission.

As part of their research, Dr Elizabeth Schulman from the Hospital of Special Surgery in New York City, and her colleagues in New York and Canada studied 1066 people with newly diagnosed rheumatoid arthritis (the Canadian Early Arthritis Cohort or CATCH study) and recorded the time it took for them to achieve remission of their arthritis. They were grouped according to their body mass index into people who were normal weight, (Body Mass Index, BMI 18.5-24.9), overweight (BMI 25-29.9) or obese (BMI >30), with about 1/3 of the sample in each group. Patients who were overweight or obese were slower to achieve sustained remission of their arthritis and also much less likely to achieve sustained remission at all.

Obese patients with early rheumatoid arthritis were 37% less likely to achieve remission of their arthritis than people of normal weight. The reasons for these results are not clear but possibilities include obese people needing higher than usual doses of medicines, or the fact that being overweight is associated with the “metabolic syndrome”. The metabolic syndrome is a collection of problems associated with being overweight which include high blood pressure, diabetes, high levels of lipids in the blood and also having high levels of inflammation in the body. High levels of inflammation have also been linked with increased risks of cardiovascular disease such as heart attacks and also worse x-ray damage as a result of rheumatoid arthritis.

It is already known that people who are overweight or obese are more likely to develop rheumatoid arthritis and are more likely to have more active arthritis with more tender and swollen joints when they are first diagnosed than people of normal body weight. Overweight people with rheumatoid arthritis are also more likely to develop medication-related side effects including abnormal liver function tests. The long term effects of these problems are not known but clearly if arthritis is not responding to treatment then there may be a risk to future health and well-being.

New research by Jeffrey Sparks from Brigham and Women’s Hospital, Boston has shown that losing weight can have a significant benefit for people with rheumatoid arthritis. Dr Sparks and colleagues studied 53 very overweight people with rheumatoid arthritis (BMI average 47) who underwent bariatric surgery (surgery designed to reduce food intake, for example the use of a gastric band). At the start, 57% of the group had high rheumatoid disease activity. 12 months after the surgery, the group had lost 70% of their excess weight and only 6% had moderate or high disease activity. In 74% of the group, arthritis was in remission compared to 26% at the start.

These studies highlight the importance of giving people who are newly diagnosed with rheumatoid arthritis and who are overweight or obese, advice about healthy eating and weight loss as soon as arthritis is diagnosed. Losing weight means that it is much more likely that the arthritis will respond to medication and that the risks of developing progressive joint damage will be minimised.

As part of its services, UK charity Arthritis Action offers people living with arthritis healthy eating and lifestyle advice to help them live healthier and more active lives through diet and exercise.

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