Background/Purpose: Rheumatoid arthritis (RA) is associated with an increased risk for cardiovascular disease (CVD). Urinary microalbumin is a risk factor for CVD in the general population, but its association with CVD in RA is less well defined. Thus, we examined the association between urinary microalbumin and CVD, using coronary artery calcium (CAC) and augmentation index (AIX), measures of coronary atherosclerosis and vascular stiffness, respectively.

Methods: In a cross-sectional study, we evaluated 136 patients with RA and 79 controls with no diabetes or clinical history of CVD. MA was defined as urine albumin to creatinine ratio (UACR) > 30mg/g in a spot urine. Traditional CVD risk factors such as age, gender, smoking, family history of CVD, body mass index (BMI), hypertension, and lipids were recorded, and insulin resistance (defined using the homeostasis model assessment), metabolic syndrome and Framingham risk scores were calculated. Disease duration, DAS 28 score and inflammatory markers, including vascular cell adhesion molecule-1 (VCAM-1), interleukin-10 (IL-10), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), interleukin-6 (IL-6), tumor necrosis factor-a (TNF-a), and cystatin-C, were measured in RA. Subclinical atherosclerosis was assessed using electron beam computer tomography, and arterial stiffness using AIX. We compared traditional risk factors, UACR and measures of subclinical CVD between RA and controls using Wilcoxon rank sum and Fisher’s exact test. The association between MA and CAC and AIX was adjusted for age, sex and race using linear or logistic multivariate analyses as appropriate.

Results: Patients with RA had a higher UACR [median (IQR): 7.6mg/g (4.0-15.5) than controls (5.6 (3.3-9.0), p=0.02). The presence of MA was significantly associated with HTN in RA (p=0.01). No significant association was observed with age, gender, smoking, HOMA-IR, or metabolic syndrome. In RA, but not controls, there was a significant association between AIX and log transformed UACR, β coefficient of 1.9 (95% CI 0.4-3.4), p=0.01. The association remained significant after adjusting for age, sex, and race. CAC was not significantly associated with UACR in RA or controls [Table]. UACR was significantly associated with higher levels of VCAM-1 (ρ=0.2, p=0.01) and lower levels of IL-10 (ρ=-0.2, p=0.02) in RA.

Table. Association between UACR and subclinical CVD in RA and controls:

		UACR
		Unadjusted		Adjusted for age, sex, and race
		b coef. (95% CI)	P value	b coef. (95% CI)	P value
AIX	RA	1.9 (0.4-3.4)	0.01	1.5 (0.1-2.8)	0.03
	Controls	-1.3 (-3.6-1.0)	0.26	-0.9 (-2.8-1.0)	0.34
		OR (95% CI)	P value	OR (95% CI)	P value
CAC	RA	0.9 (0.7-1.2)	0.64	0.7 (0.5-1.1)	0.13
	Control	0.6 (0.4-1.1)	0.11	0.7 (0.4-1.3)	0.31

Conclusion: Urinary microalbumin is increased in patients with RA compared to controls and is associated with increased arterial stiffness as measured by AIX in RA, independent of other CVD risk factors. MA is not associated with CAC. In RA, urinary microalbumin is associated with higher levels of VCAM-1, which mediates the adhesion of inflammatory cells to vascular endothelium, and with lower levels of IL-10, an anti-inflammatory cytokine.

---

« Back to 2013 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/urinary-microalbumin-is-associated-with-arterial-stiffness-in-patients-with-rheumatoid-arthritis/