AB1027 The predictive value of cystatine c for gouty nephropathy
Authors: D. Rekalov, I. Daniuk, G. Medvedchuk
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Gout is the most common cause of an inflammatory arthritis in men elder than 30 years, varies up to 1,7% of the total morbidity. One of the most common complication of chronic gout is gouty nephropathy with the morphological signs of kidney damage, even in the early stages.<sup>1</sup> It's well known, that urine albumin and glomerular filtration rate (GFR) are the generally accepted markers of nephropathy. But, recent data has shown, that the informative and obtainable new biomarkers of the kidney function are still needed. Thus, evaluation of the pathogenic role in the renal failure of cystatin C could be a "clue". The dozen trials have shown that an increasing of ranges cystatin C in serum could be tested at the stage of subclinical reduction of GFR with normal level of creatinine.<sup>2; 3</sup> <h3>Objectives</h3> To determine the serum ranges of cystatin C and creatinine as the markers of nephropathy in patients with gout. <h3>Methods</h3> The main group was the 80 males with primary gout (average age – 53,4±8,2 years), with the disease duration from 3 up to 25 years. The second group – 20 healthy men (49,5±4,5). We determined the concentration of serum uric acid, serum cystatin C, creatinine, calculate the GFR using CKD-epi formula. For urine albumin evaluation we used the albumin/creatinine ratio in the morning urine portion. <h3>Results</h3> e determined that the main group identified by more significant violations of renal function. In the main group was found the statistically significant increase of the serum creatinine (97±18 μmol/l) and decrease of GFR (73<sup>64; 94</sup>) ml/min<sup>2</sup>. The serum cystatin C concentration in the main group was (1,7<sup>1,4; 1,9</sup>) mg/l which was the significantly larger than in the comparison group (0,8 [0,7; 0,92] mg/l, p&lt;0,001). The albumin/creatinine ratio was statistically higher in the main group (26<sup>14; 56</sup>) mg/g than in comparison (0,8 [0,7; 0,92]) mg/l, p&lt;0001. Also the patients with gout are characterised by the larger concentration of uric acid in the serum (530±74) μmol/l than healthy men (347±75) μmol/l and negative correlation between uric acid level and GFR (r=-0,4, p&lt;0,05) which explain the increase of uric acid concentration in the serum. We determined the correlation between level of urine alabumin and creatinine concentration (r=+0,5, p&lt;0,05) in the main group, but concentration between albuminuria and cystatin C was stronger (r=+0,6, p&lt;0,05). We detected that cystatin C level had a greater accuracy for the diagnosis of albuminuria than creatinine according to the ROC-analysis. These facts show that serum concentration of cystatin C more closely connected with the renal function than creatinine. <h3>Conclusions</h3> 1. The increase of serum cystatin C level can be identified before the clinical manifestation of renal dysfunction while the serum creatinine remain relatively normal. 2. Serum ranges of cystatin C more closely correlate with elevation of urine albumin than creatinine. <h3>References</h3> [1] Michael H. et al. Gout and Its Comorbidities/H. Michael Pillinger, S. David Goldfarb, et al. //Bulletin of the NYU Hospital for Joint Diseases. – Vol. 68(3). – P [2] Servais A., et al. Is serum cystatin-C a reliable marker for metabolic syndrome? A. Servais, P. Giral, M. Bernard, et al. //Am. J. Med. – 2008. – Vol. 121 (5). – P. 426–32. [3] Turk V., Stoka V., Turk D. Cystatins: biochemical and structural properties, and medical relevance/V.Turk, V. Stoka, D. Turk//Front Biosci. 2008. – Vol.13. – P. 5406–5420. <h3>Disclosure of Interest</h3> None declared