[Malnutrition and obesity among patients with rheumatoid arthritis and chronic inflammatory process].

Chronic inflammatory status in patients with rheumatoid arthritis (RA) due to metabolic changes has an effect on body composition. Up to two thirds of patients may be affected by the loss of body cell mass and, thereby, malnutrition including its most severe form - cachexia. Among patients with RA and malnutrition, the total body weight is not reduced and the muscle loss is partially compensated by an increase in body fat. The excess of visceral and trunk adipose tissue is the main factor of increased prevalence of insulin resistance and metabolic syndrome in RA patients. On the other hand, an increased level of abdominal obesity in RA patients is related to the decreased concentration of adiponectin and reduced joint damage, which determines the reduced level of functional impairment. This is the reason why body mass index (BMI) is especially inadequate indicator of body composition in RA patients. In clinical practice, even though BMI is an inadequate body composition indicator, low BMI values in RA patients can be used to detect a particularly fragile sub-set of patients that deserve particular attention. RA patients with BMI intermediate values probably have good control of the disease but they can nonetheless be malnourished. Obese RA patients may or may not have better articular prognosis but should be subjected to the same degree of attention regarding cardiovascular risk factors as obese subjects in the general population. Irrespective of the inflammatory process, body composition is the result of a complex network of interconnected factors, like physical activity, nutritional intake and chronic corticosteroid treatment.