Urinary thrombomodulin in patients with rheumatoid arthritis: relationship to disease subset.

In 110 patients with rheumatoid arthritis (RA), the mean (+/- SD) urinary thrombomodulin (TM) concentration was 74.4+/-19.5 ng/mg creatinine (Cre), which was significantly higher than the mean in age-matched healthy controls (49.9+/-10.8 ng/mg Cre; p<0.0001). The mean urinary TM concentration in the RA subset with least erosive disease (LES) was 65.2+/-12.4 ng/mg Cre (n = 41), with more erosive disease (MES) was 77.4+/-20.4 ng/mg Cre (n = 58) and with mutilating disease (MUD) was 92.6+/-20.2 ng/mg Cre (n = 11). TM in the MUD group was the highest of the three subsets (ANOVA, p<0.0001). By contrast, the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in the MES and MUD groups were not significantly different. Urinary TM levels may allow differentiation of RA subsets, unlike markers of inflammation such as ESR and CRP.