The association among uric acid, microalbumin and estimated glomerular filtration rate in hypertensive patients: a case control study.

Objective: To estimate the relationship among uric acid (UA), 24-h microalbumin (24 h-MAU) and estimated glomerular filtration rate (eGFR) in hypertensive patients.
Method: The study enrolled adult patients hospitalized in TEDA International Cardiovascular Hospital. The study was used to explore the correlation among UA, 24 h-MAU and eGFR. Univariate analysis was used to compare continuous or categorical data groups according to data type. Multivariate analysis was used to explore the correlation among UA, Log 24 h-MAU and eGFR by linear regression, and the relationship among UA, 24 h-MAU ≥ 30 mg/24 h (increased 24 h-MAU) and eGFR < 90 ml·min ^-1 ·1.73 m ^-2 (mildly decreased eGFR) by logistic regression. Mediation effect analysis was used to explore the mediating effect of increased 24 h-MAU between UA and mildly decreased eGFR. Subgroup analysis was used to investigate the correlation among UA, 24 h-MAU and eGFR in different gender.
Result: Seven hundred and thirty-three inpatients were enrolled in the study, including 257 patients with hyperuricemia. The level of UA was 377.8 ± 99.9 μmol/L in all patients enrolled, and it was about 50.1% higher in hyperuricemia group (482.3 ± 58.8 μmol/L vs. 321.4 ± 63.5 μmol/L, P < 0.001). The prevalence of hyperuricemia was 35.1% (95%CI 31.6-38.5%). The univariate regression analysis showed that UA was significant related to Log 24 h-MAU, increased 24 h-MAU, eGFR and mildly decreased eGFR. After adjusted confounding factors, UA was significant related to Log 24 h-MAU (β = 0.163, P < 0.001), eGFR (β = - 0.196, P < 0.001), increased 24 h-MAU (quantitative analysis: OR = 1.045, 95%CI 1.020-1.071, P < 0.001; qualitative analysis: OR = 2.245, 95%CI 1.410-3.572, P = 0.001), but had no significant relationship with mildly decreased eGFR. Mediating effect analysis showed that increased 24 h-MAU partially mediated the relationship between UA and mildly decreased eGFR (relative indirect effect: 25.0% and 20.3% in quantitative analysis and qualitative analysis respectively). In the subgroup analysis, the results were stable and similar to the analysis for entry patients.
Conclusion: The prevalence of hyperuricemia was higher in hypertensive inpatients. UA was strongly associated with Log 24 h-MAU, eGFR and increased 24 h-MAU, while the correlation with mildly decreased eGFR was affected by multiple factors. And increased 24 h-MAU might be the intermediate factor between UA and mildly decreased eGFR.
(© 2023. The Author(s).)