Disabled by Weight: Obese with Arthritis

Morbidly obese inflammatory polyarthritis patients had higher risk of disability

(RxWiki News) Being obese is just plain unhealthy. All that excess fat can make outcomes worse for patients with any of a number of diseases, including rheumatoid arthritis.

A recent study showed that morbidly obese patients with inflammatory polyarthritis - which includes diseases like rheumatoid arthritis - had higher levels of disability than arthritis patients who were not obese. Morbidly obese patients had about twice the odds of disability compared to those who were not obese.

According to the authors, doctors should be aware of the link between morbid obesity and disability when caring for patients.

"Control your weight to help prevent disability from arthritis."

Obesity is diagnosed using the body mass index (BMI) - a measure of body fat using height and weight. If a person has a BMI over 30, that person is considered obese. A BMI over of 35 or more is considered morbidly obese. Morbid obesity puts people at risk of a number of illnesses, including diabetes, heart disease and osteoarthritis.

Deborah Symmons, MD, FFPH, FRCP, of the University of Manchester in the United Kingdom, and colleagues set out to study the relationship between BMI and disability in a large group of patients with inflammatory polyarthritis.

Inflammatory polyarthritis is any arthritis that involves inflammation (swelling and pain) of multiple joints.

The study included 1,246 patients 16 years of age and older with at least two swollen joints for four weeks or more. Of these patients, 63 percent met the criteria for rheumatoid arthritis.

At the beginning of the study, researchers examined participants' joints and measured their height and weight. Researchers also took blood samples to measure markers of arthritis.

To measure disability, patients completed the Health Assessment Questionnaire (HAQ). A higher HAQ score is a sign of higher disability.

Results showed that a BMI of 35 or more was associated with a higher HAQ score. In other words, morbid obesity was associated with higher levels of disability.

The odds of disability were anywhere between 1.95 and 2.43 times higher among morbidly obese arthritis patients than among those who were not morbidly obese.

"In conclusion, we have shown that morbid obesity is independently associated with HAQ disability in patients with inflammatory polyarthritis," the authors wrote.

"This result needs to be verified in other early arthritis cohorts; nevertheless, the role of obesity should be taken into consideration when interpreting HAQ scores in clinical practice. Importantly, these patients may need greater input from the multidisciplinary team to help them manage their limitations in activities of daily living."

The authors also pointed out some limitations to their study. First, many patients had missing data. Second, the researchers identified obese patients using BMI, which they called "a crude measure of body composition." Lastly, the study included patients with inflammatory polyarthritis rather than only rheumatoid arthritis patients. However, the authors point out that more than 75 percent of inflammatory polyarthritis patients go on to develop rheumatoid arthritis within five years.

The study - which was funded by Arthritis Research UK - was published December 27 in Arthritis Care & Research. The authors disclosed no conflicts of interest.

Review Date: 
January 17, 2013