Elevated serum uric acid is an independent risk factor for the loss of renal function

Objective To investigate the relationship between serum uric acid level and renal function decline by retrospective cohort study. Methods Through the physical examination system of the First People's Hospital of Foshan, the physical examination data from 2015 to 2018 of a public institution in Foshan city were obtained. The gender, age, blood cell analysis, liver function, serum creatinine, uric acid, fasting blood glucose were obtained. The change of eGFR (ΔeGFR=eGFR2018-eGFR2015) was analyzed. Results A total of 2505 subjects were followed up for four years. The subjects were divided into ΔeGFR ≥0 group and ΔeGFR<0 group. There were 845 subjects in ΔeGFR ≥0 group, and 1660 subjects in ΔeGFR<0 group. Compared with that in ΔeGFR<0 group, the base-level of uric acid in ΔeGFR ≥ 0 group was higher [(349.48±87.62) μmol/L vs (325.72±82.58) μmol/L, t=6.669, P<0.001], but the rate of uric acid decline was greater [-15.00(-53.50, 17.00) μmol/L vs 15.50(-18.00, 49.00) μmol/L, Z=-13.470, P<0.001]. According to the levels of uric acid in 2015 and 2018, then the subjects were divided into four groups, normal to normal group (N-N, 1551 cases), normal change into high uric acid group (N-H, 299 cases), high uric acid drop to normal group (H-N, 238 cases), and high to high uric acid group (H-H, 417 cases). The ΔeGFR was -1.58(-4.17, 1.01) ml·min-1·(1.73 m2)-1 in N-N group, and -3.60(-7.24, -0.98) ml·min-1·(1.73 m2)-1 in N-H group, -0.20(-3.14, 3.27) ml·min-1·(1.73 m2)-1 in H-N group, -0.96(-4.07, 1.93) ml·min-1·(1.73 m2)-1 in H-H group, respectively. The ΔeGFR decreased most significantly in N-H group than the other three groups (χ2=103.130, P<0.001). Multivariate logistic regression analysis showed that elevated uric acid was an independent risk factor for eGFR decline (OR=1.739, 95% CI 1.587-1.906, P<0.001), while elevated indirect bilirubin (OR=0.968, 95% CI 0.943-0.993, P=0.013), elevated red blood cells (OR=0.815, 95% CI 0.680-0.976, P=0.026) were independent protective factors for eGFR decline. Conclusion Elevated uric acid is an independent risk factor for the decline of renal function. Good control of hyperuricemia is beneficial to the protection of renal function. Key words: Uric acid; Hyperuricemia; Glomerular filtration rate; Risk factors