Urinary Albumin Excretion and Vascular Function in Rheumatoid Arthritis

Urinary albumin excretion in rheumatoid arthritis is not associated with markers of vasculopathy in distal microvascular beds

OBJECTIVE

Increased UAE is a marker of generalized vascular damage in high-cardiovascular risk patients. However, it remains unknown whether it corresponds to a state of diffuse vasculopathy in high-risk patients with RA.

METHODS

UAE was estimated in 24-hour urine samples in RA and non-RA individuals. Retinal arteriolar and venular diameters were calculated from retinal images with computerized software. SEVR was estimated as an index of microvascular coronary perfusion with applanation tonometry. Dermal capillary density was measured from images obtained with nailfold capillaroscopy, using specifically designed software.

RESULTS

In a total of 111 individuals, neither UAE (5.1 [2.8-10.8] vs 6.5 [3.0-11.7] mg/24 h) nor prevalence of microalbuminuria (11.0% vs 8.1%) significantly differed between patients (n = 74) and controls (n = 37). In the RA group, UAE was not significantly associated with inflammation, nor with any of the studied microvascular indices of the retinal microvasculature, the coronary microcirculation, and the dermal capillary network.

CONCLUSION

Among RA patients, UAE was not associated with markers of vasculopathy in distal microvascular beds. Increased UAE in RA might be primarily considered as a manifestation of localized, compromised function of the renal microvasculature, rather than a marker of generalized microvascular impairment.

The role of microalbuminuria as a predictor of subclinical cardiovascular events in rheumatoid arthritis patients and its relation to disease activity

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that affects many body tissues and leads to major morbidity and mortality. Renal disease in RA is clinically important because it restricts the management of primary disease and increases mortality. The objectives of this study are to (1) investigate the difference between RA patients with and without microalbuminuria (MAU) and (2) find out the relation between MAU and disease activity as well as subclinical cardiovascular effects. Ninety RA patients were divided into two groups according to the presence of MAU, in addition to 30 healthy volunteers. ESR, hs-CRP, RF, lipid profile, urinary microalbumin, GFR, renal function tests, carotid intima media thickness (cIMT), flow-mediated dilatation of the brachial artery (FMD), ECG, and echocardiographic examination were performed for patients and controls. MAU positive RA patients revealed significantly higher lipid profile, ESR, hs-CRP, DAS 28, cIMT, and lower FMD as well as ECG and echocardiographic abnormalities compared to MAU negative RA patients. Moreover, there was significant positive correlation between MAU and DAS28, hs-CRP, LDL, cIMT as well as negative correlation with FMD%. In our study, all RA patients with MAU had a normal serum creatinine concentration and gave a negative result with Albustix. MAU is significantly correlated with ESR, hs-CRP, lipid profile, cIMT, and FMD% in RA patients; therefore, it can be used as an index to measure disease activity as well as subclinical cardiovascular affection in RA patients.

Urinary albumin excretion in patients with rheumatoid arthritis in a large cross-sectional study

While there is a lot of evidence published on the association of cardiovascular (CV) disease and rheumatoid arthritis (RA), little is known about urinary albumin excretion (UAE)-a marker of CV risk-in this particular high-risk population. Therefore, we investigated UAE in a large cross-sectional study. We used data from the US National Health and Nutrition Examination Survey (NHANES), including the years 2007-2012. Primary outcome was the proportion of patients with a urinary albumin-creatinine ratio (ACR) >30 mg/g. A total of 14,648 study participants (representing a population size of 174,663,008) with available ACR were included in the study (14,179 without RA and 469 with RA). In the RA group, the proportion of patients with an ACR >30 mg/g was 10.46 % (95 % CI 7.47-14.45 %) and in the non-RA group this proportion was 13.39 % (95 % CI 12.65-14.16 %; p = 0.09). There was a strong association between RA and DM (OR 5.84; 95 % CI 4.48-7.62). In the RA group, significantly more patients had a former CV event (OR 3.01; 95 % CI 2.28-3.97). Adjustments for DM, smoking status, former CV event, age, systolic blood pressure, and gender did not substantially alter the association between RA and ACR >30 mg/g (OR 0.82; 95 % CI 0.51-1.33). We did not find evidence for a difference in UAE in patients with or without RA, despite the fact that RA was associated with DM and, in addition, RA patients more often had a previous CV event. These findings may support the assumption that despite an increased CV risk, UAE does not play a major role in RA patients.