Serum Uric Acid/Serum Creatinine Ratio and Chronic Vascular Lesions on Renal Biopsy: A Retrospective Observational Study

Introduction Increased serum uric acid (SUA) levels are found in cardiovascular and kidney diseases, associated with the development of vascular injury. Uric acid stimulates the inflammatory pathways, promotes vascular smooth muscle cells proliferation, activates renin-angiotensin system leading to the development and progression of vascular damage. Renal function-normalized uric acid [SUA to serum creatinine ratio (SUA/SCr)] has been suggested to be a better indicator of uric acid. Aim To investigate the correlation between SUA level and SUA/SCr in the development of chronic and vascular lesions (CVL) in patients with primary glomerulonephritis (GN). Methods A retrospective observational study was conducted in 95 consecutive renal native biopsies performed at Policlinico Umberto I of Rome (Italy). Patient inclusion criteria were age >= 18 years, a renal biopsy confirming diagnosis of primary GN, the availability of complete demographic, clinical, pathological, and laboratory data. Results Median SCr was 1.06 mg/dl (IQR 0.77;1.70) with a median eGFR of 70.40 ml/min (IQR 40.40;105). Median SUA was 5.90 mg/dl (IQR 4.30;6.90) and median SUA/SCr was 4.70 (IQR 3.20;6.80). CVL were reported in 56 (58.9%) patients. Median SUA/SCr was significantly lower in patients with CVL than patients without CVL [3.95 (IQR 2.65;6) vs 5.90 (IQR 4.30;7.20), p<0.01]. Logistic regression analysis showed that SUA/SCr <= 4.05 [OR 5.451 (95% CI 1.222;24.325), p<0.05] was independently associated with CVL. Conclusions CVL play a crucial role in the progression of kidney disease. SUA/SCr <= 4.05 is associated with CVL in patients with primitive GN.