Urinary Albumin Excretion and Vascular Function in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is associated with significant cardiovascular (CV) morbidity and mortality. Increased urinary albumin excretion is a marker of CV risk. There are only few data on urinary albumin excretion in RA patients. Aim of the present study was to investigate urinary albumin excretion in RA patients and analyze, whether there is an association between urinary albumin excretion and vascular function as measured by the augmentation index (AIx). In a total of 341 participants (215 with RA, 126 without RA) urinary albumin-creatinine ratio (ACR) was determined and the AIx was measured. The Kolmogorov-Smirnov-test was used to cluster patient groups whose distributions of ACR can be considered to be equal. A crude analysis showed a median ACR of 6.6 mg/g in the RA group and 5.7 mg/g in patients without RA (P > 0.05). In order to account for diabetes (DM) we formed 4 distinct patient groups. Group 1: RA-/DM- (n = 74); group 2: RA+/DM- (n = 195); group 3: RA-/DM+ (n = 52); group 4: RA+/DM+ (n = 20). Clustering of these groups revealed two distinct patient groups: those without RA and DM, and those with either RA or DM or both. The latter group showed statistically significant higher ACR (median 8.1 mg/g) as the former (median 4.5 mg/g). We found no significant correlation between AIx and ACR. Urinary albumin excretion in patients with RA or DM or both is higher than in subjects without RA and DM. This can be seen as a sign of vascular alteration and increased CV risk in these patients.