Albuminuria in Rheumatoid Arthritis: Associations With Rheumatoid Arthritis Characteristics and Subclinical Atherosclerosis

Abstract

Objective: Albuminuria is a marker for subclinical cardiovascular disease (CVD) in the general population. It is uncertain whether this association is present in patients with rheumatoid arthritis (RA), a population with increased atherosclerosis and CVD events. Methods: Urine albumin from a spot morning collection was measured, and the urine albumin-to-creatinine ratio (uACR) was calculated for RA patients and a population-based sample of demographically matched non-RA controls. Associations of elevated uACR (≥25 mg/gm for women and ≥17 mg/gm for men) with CVD risk factors and measures of atherosclerosis (coronary artery calcification, ultrasound-determined maximal intima-media thickness of the common carotid artery and internal carotid artery [ICA], and the presence of focal plaque in the ICA) were compared cross-sectionally according to RA status. Results: We compared 196 RA patients with 271 non-RA controls. Elevated uACR was found in 18% of the RA patients compared with 17% of the controls (P = 0.89). After adjustment, RA was associated with 57% lower odds of elevated uACR (P = 0.016). Higher serum creatinine levels and hypertension were both strongly and significantly associated with elevated uACR in the control group but not in the RA group (both P for interaction < 0.05). Among RA characteristics, the adjusted prevalence of elevated uACR among those treated with tumor necrosis factor inhibitors was less than half that among those not so treated (9% versus 20%, respectively; P = 0.047). Conclusion: There was no association in the RA group of elevated uACR with measures of atherosclerosis or with several key cardiometabolic risk factors, which suggests a lower usefulness of elevated uACR as an indicator of subclinical CVD in RA.