Relevance of urinary excretion of alcian blue-glycosaminoglycans complexes and hydroxyproline to disease activity in rheumatoid arthritis.

Urinary excretion of glycosaminoglycans (GAG) and hydroxyproline was studied in 42 adult patients with rheumatoid arthritis (RA). A significant increase of GAG and hydroxyproline was found in RA patients compared to normal controls. RA patients fulfilling the criteria of disease activity were found to have urinary excretion of GAG and hydroxyproline higher than of RA patients not fulfilling these criteria. No significant correlation however was observed between urinary GAG and hydroxyproline. GAG and hydroxyproline excretion might be the expression of cartilage destruction and bone involvement and both may be related to the activity of the rheumatoid process.