Inflammatory response and body composition in chronic obstructive pulmonary disease

Weight loss in chronic obstructive airways disease (COPD) is associated wit h an increased energy cost of breathing. To determine an association betwee n body composition and the inflammatory response we studied 80 clinically s table patients. Body composition was determined anthropometrically and skel etal muscle mass was determined as the creatinine-height index (CHI). Forty patients had their nitrogen balance determined. Circulating concentrations of interieukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), and thei r soluble receptors were determined for 68 patients. Body mass index (BMI) was normal (> 20 kg/m(2)) in 55 patients, of whom 17 (31%) had a low CHI (< 80% predicted). A reduced CHI was associated with increased circulating le vels of IL-6 (p = 0.001), TNF-alpha (p = 0.032) and their soluble receptors IL-6sr (p = 0.002), TNF-alpha sr1 (p = 0.03), and TNF-alpha sr2 (p = 0.001 ). Patients with a normal. BMI and low CHI had inflammatory mediator levels similar to patients with a low BMI and CHI; both were significantly greate r than in those with a normal BMI and CHI. Nitrogen balance was similar bet ween normal and low CHI groups, although nitrogen excretion was significant ly increased in the low CHI group. Skeletal muscle loss in CORD is probably multifactorial in origin, but our data suggest a link with systemic inflam mation, even when weight loss is inapparent.